It has been well known for a long time that the metabolisms of smaller animals are faster when compared to the metabolisms of larger animals relative to their body size. In 1883, German physiologist Max Rubner tried to define a scaling principle based on the laws of thermodynamics and geometry. The metabolism of an organism works like a perfect machine that continuously converts one form of energy into others. It also releases energy while doing so. Metabolic speed can be described as the speed at which cells convert nutrients into energy. This energy is utilized for the execution of cellular functions and the construction of new cells.

Calculations have shown that the speed of metabolism is directly proportionate to body mass. For instance, the biomass of a hamster is eight times bigger than a mouse. According to this ratio, one would expect the metabolism of a hamster to be eight times faster than that of a mouse. Similarly, the body mass of a hippopotamus is 125,000 times larger than a mouse; therefore its metabolism would be estimated to be 125,000 times faster.

The problem is that a hamster generates eight times more heat than a mouse. Furthermore, the total body surface area, which is how the heat energy leaves the hamster?s body, is four times bigger than the surface area a mouse has. Consequently, as the body of an organism grows, its surface area develops more slowly compared to its mass.

This situation is shown in Figure 1. Here a mouse, a hamster, and a hippopotamus are represented in spheres. As the spheres get larger, their volume and surface area also gets bigger. In geometry we know that the volume of a sphere is given as? ?(r is the radius of the sphere). The surface area of a sphere is also expressed as . In this case we can say that while the volume of a sphere is scaled with the cubed radius, the surface area of a sphere is scaled with the squared radius. In other terms, the volume of a sphere is directly proportionate to the cubed radius, as is the surface area of the sphere to the squared radius.

Figure 1. The scaled features of a mouse, hamster, and hippopotamus. Taken from Complexity: A Guided Tour by Melanie Mitchell, Oxford University Press.

Figure 1 displays the first model used by scientists when the relation between metabolic speed, body mass, and surface area was being investigated. According to this early model, the association between body mass, surface area, and volume was studied with spheres that encased organisms. As the volume of the sphere approximately provided the volume of the organism, the sphere?s surface area also represented the surface area of the organism (of their skin). According to this, the radius of the sphere containing the hamster is nearly twice as large as the radius of the sphere with the mouse. Therefore, it can be claimed that the volume of a hamster is approximately eight times the volume of a mouse, and its surface area is four times larger. When it comes to the hippopotamus; the radius of the sphere is 50 times larger than the one with the mouse; this shows it has a 2500 times wider surface area and a 125,000 times larger volume compared to the mouse.

As it can be seen with these examples, while the radius of the sphere increases, its surface area does, too, but at a slower ratio compared to the volume ? in other terms, it gets scaled.

Based on this model, since the surface area is scaled (enlarged) with the square of the radius, and the volume with the cube of the radius, it can be estimated that the surface area is scaled with 2/3 the power of the volume.

The interesting point that all these rough calculations take us to is that the surface-area width of the living things is adjusted in a way to permit the release of energy they generate into their surroundings in a healthy pattern. If a hamster generated more heat than the amount corresponding to four times its surface area, this would lead to the hamster overheating.

In a similar way, if you elevated the heat in a hippopotamus, which generates 125,000 times more heat than a mouse does, by eight, the hippopotamus would suffer from heat exhaustion. This is because the surface area of a hippopotamus is only 2500 times bigger than a mouse. This is called the ?surface hypothesis,? and until it was discovered that it does not correlate well with the experimental data, scientists carried out investigations based on this model for nearly 50 years.

Around 1930, Swiss animal scientist Max Kleiber performed a series of studies involving the metabolic speed of various animals. The data he collected showed that the metabolic speed is scaled to ? the power of body mass, or Metabolic speed = body mass3/4.? This is called the power law in science. Instead of the 2/3 power in the first model, the correlation of 3/4 power with the experiments demonstrated that animals, especially large ones, have higher metabolic speeds than the first model predicted.

In summary, the establishment and maintenance of this equilibrium requires knowledge beyond geometric calculations, and makes it impossible to explain via random occurrences.?

In Figure 2, the scaling of different animals in regard to their body mass is charted. The horizontal axis shows the body mass in kilograms, whereas the vertical axis marks the speed of their average basal metabolism in watts. The symbols displayed as dots are real values measured from different animals and the fact that these dots align almost on a line show the correlation of the metabolic speeds of organisms with 3/4 the power of their body masses. This points to an extraordinary order in the universe, one that has been created with perfect harmony built into it. ?

One feature of the ?power law? is that when the two axes are drawn logarithmically, the relation between the two physical magnitudes appears as a line. Here, a similar situation is present and this power law is called the ?Kleiber Law.? This law successfully provides the metabolic speeds of mammals, birds, fish, plants, and even single celled organisms.

There are also other scaling relations pertaining to these that have confounded biologists for a long time. For example, the bigger a mammal is, the longer its life span is. There are examples, like humans, who do not fit into this general principle. However this is applicable for many mammals. The life of a mouse lasts two years, typically, whereas the life of a pig is around 10 years ? and elephants live for 50 years. If you chart the average life span of many different species across their body masses, the value of the power law is seen as ?. In other terms, for mammals, the average life span is scaled to ? of the body mass (directly proportioned).

As another example of proportion and scale, if you draw a graphic displaying how the average heart beat speed changes against the body mass of different species, you will once again find the scale of the power law to be ?. This means that the larger the body mass of a mammal, the lower its heart beat is.

Biologists are trying to solve the mysteries among the relations of many power laws like this one. There is no doubt among scientists regarding the fact that these power laws manifest certain common features in living things as an important sign pointing to the presence of very significant common features for all organisms.

Figure 2. Metabolic speeds of different animals according to their body masses. Taken from Complexity: A Guided Tour by Melanie Mitchell, Oxford University Press.

The creation of living things according to a power law, which is a relation between their metabolic speeds and body sizes, is a wisdom that requires thanksgiving. To safely release their generated energy, the metabolic speeds of living things must be scaled to ? the power of their body mass. A lower value would cause a higher body heat, and a higher value would lead to very low body heat. In both situations it would not be possible for organisms to sustain their lives in the physical world. Our bodies are perfectly scaled for us to survive.

Note

Experimental values were obtained from the book of – K. Schmidt-Nielsen, Scaling: Why is animal size so important?, Cambridge University Press, 1984.

Reference

• Complexity – A Guided Tour, Melanie Mitchell, Oxford University Press, 2009.

The number of taxonomically defined animal species is around 1.5 million. These are classified into 32 phyla according to their distinct features. One of these is the phylum of Tardigrada.

These cute, tiny water creatures were discovered in 1773 by Johann August Ephraim Goeze. Despite being aquatic, these animals were called “water bears” because of their legs; and because of their resemblance to pandas, they were named “Tardigrada,” meaning “slow stepper,” by the Italian biologist Lazzaro Spallanzani. Tardigrades also look like dwarf rhinos and armadillos. There are about 1,000 different species in the Tardigrade phylum.

Tardigrades live in habitats with variable amounts of humidity, from high mountains to deep oceans, and from polar regions to the equator. They are especially found in lakes, freshwater springs, or on stone walls, mosses, lichens, leaves, and litter.

As cute, charismatic, miniature animals, tardigrades can be seen under a microscope. The length of adults can reach 1.5 mm, while the smallest ones are under 0.1 mm; their larval length is only around 0.05 milimeters. Their body is covered with a strong but elastic material.

Animals grow in two ways: via an increase of cell numbers or the enlargement of a single cell. In Tardigrades, generally the latter is observed. These animals possess a hard external skeleton, like insects, and this structure changes as they grow.

Their bodies are composed of five sections: a distinct head in addition to four body parts, each equipped with claws. They walk using the short, blunt feet under their bodies. Their clawed legs help them cling to sand particles or plant surfaces. Their hind legs are used for snatching and slow acrobatic movements. They have a sharp mouth, called a “stylet,” which enables them to consume plant cells, algae, small invertebrates, and even their own kind.

They are provided with anatomical and physiological features similar to larger animals, including a digestive track and system: a mouth, esophagus, stomach, small intestine, anus, well developed muscles, a pair of abdominal nervous systems, and a brain. The body lumen of Tardigrades are filled with a fluid that is in contact with every cell and this provides them with their necessary nutrition and gas exchanges without the need for a circulatory or respiratory system. Their respiration occurs throughout their body surfaces. Because of their physiology and ability to quickly reproduce, Tardigrades can be used as a model organism for education and research. The cell count of certain species of Tardigrades at birth never changes during their lives. While some species contain around 40,000 cells, some have fewer. Their reproduction can be sexual, but it also can occur via parthenogenesis (offspring development without the fertilization of the egg).

Tardigrades: Organisms of extreme conditions

Tardigrades are created with a resistance to a wide range of temperatures, pressures, and radiation. Therefore, they can live in environments where many living things die. They can survive a temperature of 150 C for minutes, and can also live at minus 200 C without suffering any damage for days; they can even stay alive at temperatures near absolute zero (−273 C).

Some Tardigrades can live at extreme low pressures, including situations approaching a vacuum, or at extreme high pressures, such as 600 times the normal atmospheric pressure. This pressure is six times the pressure present at the depths of the Mariana trench, the deepest part of the Earth’s oceans (roughly 11,000 meters). This was discovered when Tardigrades were taken to space and exposed to different pressures. When brought back to Earth, they were still alive.

They can also survive in environments with no humidity for 10 years, and they can stay alive in places where radiation is 1,000 times more (5000 Gy to 6200 Gy) than many organisms can endure (10 Gy is fatal for humans).

Hibernation – a dead phase

How does a Tardigrade stay alive in detrimental conditions?

When they are exposed to conditions unsuitable for life, they enter a semi-dead phase called Cryptobiosis. One of the most distinct changes during this state is that their metabolic speed slows down to near zero, and they experience programmed dehydration. In very low temperatures, Tardigrades’ water ratios drop from 85% to 3%. This way, damages that can occur by freezing are prevented. As is well-known, the main hazard during freezing is the cell membrane damage caused by the crystallization of cellular water.

During the dehydration stage, trehalose sugars are synthesized (this also happens when Tardigrades are faced with low temperatures). This sugar prevents possible damages to the cell membranes during freezing and water loss. This sugar is very intriguing for the pharmaceutical industry because of its potential use in the prevention of freezing-related damages in organ transplants.

Another benefit of dehydration is resistance to radiation. This is because reactive molecules generated in the cell by the effects of radiation cannot cause a reaction in a dehydrated medium; due to the low water concentration, the possibility of harmful reactions drops.

Cryptobiosis does not only take place during dehydration. It also happens during periods of low temperature (cryobiosis), high salinity (osmobiosis), and low oxygen. By being able to hibernate, Tardigrades are important for space research. Maybe during interplanetary trips, passengers could be hibernated by freezing.

Tardigrades could have other uses for medical purposes. Certain disease-causing microorganisms could be dehydrated without killing them via Cryptobiosis. This way, “weakened organisms” contained in vaccines get to be stored in a dry fashion, eliminating the need for freezers, making them easier to store and distribute. Similar technologies could also be employed for the conservation of seeds, sperms, blood, and various nutrients.

The genera Escherichia is thought to have emerged around 102 million years ago and is known as a gram-negative pathogenic bacteria mostly found in the intestines of warm blooded animals [1]. German pediatrician and bacteriologist Theodor Escherich discovered E. coli in 1885, and for many years the bacterium was simply considered to be a commensal organism of the large intestine. It was not until 1935 that a strain of E. coli was shown to be the cause of an outbreak of diarrhea among infants [2]. The reason its pathogenic properties were discovered so late is that many of its strains are harmless. However, virulent strains of E. coli can cause various diseases in humans and in domestic animals, and are also sometimes responsible for product recalls due to contamination. Gastroenteritis, urinary tract infections, and neonatal meningitis are the most commonly observed diseases in humans, and in rare cases virulent strains are also responsible for haemolytic-uremic syndrome, peritonitis, mastitis, septicaemia and Gram-negative pneumonia [2]. Various outbreaks all around the world have been caused by E. coli, causing millions of deaths and sick people and billions of dollars have been spent fighting it. Even though death rates have decreased with the evolution of modern medicine and the discovery of antibiotics, the outbreaks are still a major concern for all countries, such as the recent outbreak in Germany in 2011 affecting 3,950 people and killing 53 [3].

Its reputation has not been one of great dignity, and it has ruined the reputation of many. You may recall in 1993, the fast food chain restaurant “Jack in the Box” suffered a major corporate crisis involving E. coli O157:H7 bacteria. Four children died of hemolytic uremic syndrome and 600 others were reported sick after eating undercooked patties contaminated with fecal material containing the bacteria at locations in Seattle and the Pacific Northwest, USA. The chain was faced with several lawsuits, each of which was quickly settled but left the chain nearly bankrupt and losing customers.

But don’t these creatures have any properties to be appreciated, I wonder…

Compared to eukaryotic cells, bacteria have a pretty basic mechanism of functioning. They don’t have sophisticated organelles, and they do not have a cell nucleus where their DNA is stored. Everything is floating along all together in the cell cytoplasm (which shocks me when I reflect upon how such a small and simple organism can cause such severe pain on “highly evolved modern humanity”). It has the basic metabolic tools for survival. And even though, at first sight, it is tempting to look down on its simplicity, today we know that it is this simplicity that gives us space for making many modifications and experiments on it, whereas in more complicated cells, like animal cells, the moment a modification is made, the entire system reacts to that and causes much trouble in the process.

The turning point of E.coli making a huge impact on our lives was in 1973, when Stanley Cohen and Herbert Boyer discovered the “Recombinant DNA Technology.” This technology allowed specific genes to be isolated from one organism and cloned to another organism by the help of bacterial plasmids. The first commercial product to be synthesized by this technology was human insulin, which is used for the treatment of diabetes [4]. This brought an amazing amount of recognition and appreciation for the technology, as the practical aspect of the technology was now proven to be commercially profitable. For the insulin to be produced, the DNA sequence that encodes human insulin was synthesized and transplanted into a plasmid that could be maintained in a non-pathogenic strain of E.coli [4]. Now the bacterial host cells acted as biological factories for the production of the two peptide chains of human insulin, which, after being combined, could be purified and used to treat diabetics who were allergic to the commercially available porcine (pig) insulin, or for diabetics from certain religious groups who abstain from pork products such as Muslims, Jews, some Christian groups, and many more who have similar concerns.

This was only the start of an incredible new technology which used bacteria to produce different proteins or enzymes to cure human diseases. Today more than 200 new drugs have been produced by recombinant DNA technology and have been used to treat over 300 million people for diseases such as cancer, multiple sclerosis, cystic fibrosis, and stroke, and to provide protection from other infectious diseases. Over 400 new drugs are in the process of being tested in human trials to treat such diseases as Alzheimer disease and heart disease (to name only two) [4].

Today E.coli is frequently used as a model organism for all kinds of microbiological experiments. In the lab, E. Coli. is one of the first micro-organisms that is thought of for testing a biological experiment. The reason is that E.coli cells are cheap to purchase and to sustain. They grow easily and rapidly in lab conditions and have non-pathogenic strains, so they are not dangerous for the researches doing the experiment. Whereas purchasing more complicated cells such as cancer cells or stem cells may be very costly, and moreover, may need special lab conditions to be sustained; so before more complicated cells are purchased, the experiments are usually tried out with E.coli or some other kind of model organism. More importantly, E. coli was one of the first organisms to have its genome sequenced; the complete genome of E. coli K12 was published by Science in 1997 [5]. Other areas in which modified E.coli has helped humanity are vaccine development, bioremediation (fighting pollution), and production of immobilised enzymes [6].

One specific example of the benefit of recombinant DNA technology for the environment is its use in the paper industry. Before the 1970’s, when there wasn’t much environmental awareness in the paper producing industry, poisonous chlorine compounds were conventionally used to achieve pulp brightness of a high order in the manufacture of high-quality paper products [7]. This chemical bleaching technique precipitated a tremendous environmental concern considering the magnitude of the industry. Plants treated with elemental chlorine produced significant amounts of dioxins. Dioxins are highly toxic, and their health effects on humans include reproductive, developmental, immune and hormonal problems. They are also known to be carcinogenic. Over 90% of human exposure is through food, primarily meat, dairy, fish and shellfish, as dioxins accumulate in the food chain in the fatty tissue of animals [7]. One alternative for these chemical bleaching processes is the use of the enzyme “xylanase,” which degrades the linear polysaccharide beta-1,4-xylan into xylose, thus breaking down hemicellulose, one of the major components of plant cell walls. Even though the use of xylanases in this industry has increased significantly with the discovery of Viikarri et al. (1986), the enzyme needs further improvements for it to be commercially acceptable [6]. To ensure the commercial utilization of hemicellulosic residues in the pulp and paper industries, the production of higher xylanase yields at low capital cost is required [6]. Such studies are ongoing with the purpose of partially mutating the amino acid sequence for the purpose of especially increasing the thermal stability of the enzyme and also increasing its metabolic activity. The gene mutation and gene expressions are generally done in either E.coli or yeast cells. Davoodi et al. has mutated the enzyme up to the point where the transition temperature increased 12 0C by introducing disulfate bonds in the enzyme [8]. The wonders this enzyme can do for the health of the environment is breathtaking, and is an area which should be further studied until finding the commercially viable kind that will eliminate chemicals from the paper industry during bleaching.

Even though some controversy remains on gene transferring, its tremendous positive impact on humanity cannot be denied. I personally think that it does need constraints and strict regulations, but this technique is one of the most remarkable techniques discovered in modern times, and E.coli has no doubt played a great role in the availability of this technology.

Even though condemning E.coli and stating its “evilness” seems like the most obvious path, we all ought to appreciate the variety and uniqueness of these creatures which also allow us to produce such large varieties of drugs. We ought to appreciate its simplicity, which allows it to have a chance of producing such sophistication. We ought to reflect upon the fact that something can be classified as “good” or “bad” only by the means in which we perceive it, and the reality of it may be completely opposite of what we had thought initially.

McPen is a freelance writer in natural sciences, Montana, US.

References

1. Battistuzzi FU, Feijao A, Hedges SB. 2004. “A genomic timescale of prokaryote evolution: insights into the origin of methanogenesis, phototrophy, and the colonization of land”. BMC Evol. Biol.
2. Todar, K. “Pathogenic E. coli”. Online Textbook of Bacteriology. University of Wisconsin–Madison Department of Bacteriology.
3. “German-grown food named likely culprit in deadly outbreak”. CNN. (5 June 2010).
4. Glick, Bernard, Jack Pasternak, and Cheryl Patten. 2010. “MOLECULAR BIOTECHNOLOGY Principles and Applications of Recombinant DNA . 4th Edition.” Washington,DC: ASM Press, pp. 3-13.
5. Blattner FR, Plunkett G, Bloch CA, Perna NT, Burland V, Riley M, Collado-Vides J, Glasner JD, Rode CK, Mayhew GF, Gregor J, Davis NW, Kirkpatrick HA, Goeden MA, Rose DJ, Mau B, Shao Y (September 1997). “The complete genome sequence of Escherichia coli K-12”. Science 277 (5331): 1453–62.
6. Cornelis P. 2000. “Expressing genes in different Escherichia coli compartments”. Curr. Opin. Biotechnol. 11 (5): 450–454.
7. Beg, Q.K., M. Kapoor, L. Mahajan, and G.S. Hoondal. 2001. “Microbial xylanases and their industrial applications: a review.” Springer.
8. Davoodi J., Wakarchuk W.W., Carey P.R., Surewicz W.K. 2007. “Mechanism of stabilization of Bacillus circulans xylanase upon the introduction of disulfide bonds.” Biophysical Chemistry, 125 (2-3) , pp. 453-461.

The complex nature of genetics and its wide implications for all living organisms from viruses to humans provide raw materials for creative imaginations. In the present scenario, many consider it vital to comprehend all the genetic information necessary to support life on this universe. One of the common constraints on the understanding of genetics is the assumption that genes are the sole causes of all activities of living organisms and can explain all aspects of biological life on earth. For example, some believe the behavior and development of an organism can be predicted, if its genetic information is known-this belief is called “genetic determinism.” However, it is true that neither all aspects of inheritance are in all cases well explained, nor that the mere effect of genes on complex traits is well interpreted. The boundaries of the effects of genes on physical existence, development, survival, and the behavior of organisms are not always simple and straightforward. The capacity of humans for genetic manipulation-at least as it is commonly assumed or claimed-is limited in several ways and some of the basic causes of such barriers have yet to be explained. The focus of this article is to point out the limitations on attempts to appoint genes as the driving force of life.

The Central Dogma

Genes are small fragments of genomic DNA, encoding mRNAs which are later translated into proteins that participate in different biological metabolisms, hence conferring different traits on an organism. The biological functions and transmission patterns of genes over generations were being investigated well before the discovery of DNA as hereditary material and date back to the recognition of Mendel’s laws in the early twentieth century. Genetic information is coded in the form of a short string of DNA called a gene, which is employed in the expression of a trait(s) or mechanism(s) through synthesizing a chain of amino acids called proteins. These proteins either can be stored in different body parts or serve as enzymes in various biochemical reactions such as fighting infections. This flow of genetic information from gene–mRNA–protein synthesis is called the “Central Dogma” in biological sciences. In this biological doctrine, a very solid and predictable mechanism is assumed. Prior to the release of the human genome sequence information, the number of genes in the human genome was estimated as ~100,000. However, this estimate was far more than the actual number of genes (~35,000), which led us to question the validity of the “Central Dogma” as an explanation of the complexity of human beings. Out of these ~35,000, only 300 genes are unique to the human species.¹ This is another blow to the authenticity of the original central dogma theory. Are those 300 genes the foundation of all humankind and do they distinguish us from the rest of the mammals? Reducing humankind to its biology and explaining it based on genes has been questioned extensively and could be the subject of another discussion. But even considering such a view valid for purely practical purposes, the big gap between humans and other mammals cannot be due to the existence of this small number of genes.

Recent scientific discoveries have revealed a key point about the structure of genes-that each gene has a set of sub-segments called exons. Each exon can make a new protein. Hence, the gene can be the template for more than one protein. In the presence of other genes and proteins, the code of a particular gene can yield different kinds of proteins under variable circumstances. The flow of information can be both ways, and hence there are no predetermined factors controlling the flow of information. That means, we might know the information on what genes are present, and we can even decode it to know what is in there, but we cannot be sure what result (proteins in this context) will come out at the end when it is in the context of real life.

From physical characteristics to their genetics

Working back from a particular trait and trying to infer the genes that are involved in expression of such trait is a different approach to reveal the role of genes but surely it is not an easy task. Traits that are expressed by a single gene or a small number of genes are known as Mendelian/qualitative traits and their pattern of inheritance is simple and detection of the gene(s) is straightforward. Some of the disease resistance in plants and blood groups in humans are classic examples of Mendelian traits. The main distinction between such traits and the quantitative ones is their discreteness. For example a human being can have only one of four blood types: A, B, AB or O, and each of these groups is solid and no other blood types exist in between. In this type of trait, the role of a particular gene(s) is usually predictable and the pattern of transmissions over generations both for the future and the past can be inferred.

However, only a small percentage of traits is qualitative and expresses Mendelian inheritance. Most traits, such as intelligence, skin color in humans, height of an organism, seed yield of a grain, and diseases that have genetic causes like cancer, are quantitative traits and complex in nature. The ultimate phenotype (what we can see or measure from a trait) emerges from the joint effect of many genes as well as interaction with the particular environment in which the individual develops. The number of genes that is involved in the expression of a particular trait can be hundreds or even more. An objective assessment of each trait and quantification (called the phenotype) is impractical in most cases and could lead to another discussion. But assuming that we can measure a trait feasibly, the inference of genetic bases could still be controversial. Considerable efforts have been devoted to unveiling the effect of genes in the expression of complex traits whose inheritance pattern deviates from Mendelian inheritance. A special genetic technique, known as genetic mapping, is used to identify multiple genes that underlie a complex trait and this has practical applications for crop improvement. In humans, efforts are directed toward the detection of genes which predispose to complex inherited diseases. In this type of situation, the effects of genes on a trait are additive and can only explain a certain amount of change in the trait that we are interested in. Detection of all genes involved in the expression of a quantitative trait is practically impossible. The environment is an important factor with a pivotal role in the expression of such traits. The term “environment” is not restricted to what is present within the cell or surrounding the cell or individual. It rather refers to larger scale effects in the process of biological life that cannot be explained by genetics and the term can be used interchangeably with non-genetic effects.

One of the most striking examples of the role of genes on the expression of the phenotype is the presence of differences between identical twins. Despite the fact that they have completely identical sets of genes, studies have shown that twins can indicate different degrees of psychiatric diseases such as bipolar disorder.² Similar phenomena may be observed in crop species. In crop breeding programs different varieties are usually tested in different environments. In most cases varieties rank differently based on their performance in different environments.³

Genetic background

Genes that do not code any information for the trait of interest can also be a part of the process of expression of the trait. In other words, certain genes can be employed to stop or alter the function of a particular gene. Modifying the utility of a gene can also be done by a series of complicated reactions within each organism through mechanisms known as epigenetics. This type of alteration in gene function is also observed empirically during the process of transferring genes between different organisms through genetic engineering.⁴ Most transferred genes are silenced (turned off) by different mechanisms in a new organism regardless of patterns of inheritance. This is particularly interesting because it clearly indicates that the existence of a particular gene in the body does not necessarily guarantee that it will be functional. Even if it is functional in one individual, it might be silent in others. Even if a gene is functioning in all the individuals carrying it, the degree of expression may be variable.

The end of genetic determinism

With the discovery of the code of genes, we now know more about the biology of living organisms than ever before, as new genetic tools have enabled us to better understand what kind of information is stored in each gene.

Most of the traits of living organisms are affected by the existence of many genes as well as non-genetic effects (denoted as environment in genetics). Although Mendelian traits can be predictable to some degree, yet we can not completely infer all the genes that are employed in the expression of a complex trait, nor the amount of contribution from each single gene and portion attributed by non-genetic factors. So we cannot determine the presence of genes by simply observing the phenotype or expression of a trait.

Considering each individual gene separately will allow us to understand its possible functions more clearly and accurately. Nevertheless, the knowledge of possible functions and structure is not enough to predetermine if the information coded in the gene will be used by the organism, and, even if it will be used, how much of that information will be processed is uncertain. Whether the information that is processed will be observed or not is another ambiguity.

Assuming that we can and will know all components of life by having the knowledge of genes is known as genetic determinism. In some cases, genes are described as independent entities that drive living organisms and manage life because of the assumption that their presence will be enough to predetermine all the biology and the behavior of an organism.

Simply, in order for a gene to be an independent agent by itself, it needs to have the knowledge of all other genes as well as all the non-genetic factors for expression of a simple trait. In reality, genes contain a very limited amount of knowledge which makes them no more than tools or parts of living organisms that are employed in the existence of life on earth. Biological life itself is incredibly complex and its sustainability requires a more comprehensive knowledge that is beyond our current understanding based on the genetic code.

Seyyidhan Mirza is a PhD candidate of Plant Breeding, Genetics, and Genomics. He can be contacted at seyyidmirza@gmail.com.

Notes

1. Siepel A., M. Diekhans, B. Brejová, L. Langton, M. Stevens, C. L.G. Comstock, C. Davis, B. Ewing, S. Oommen, C. Lau, H. Yu, J. Li, B. A. Roe, P. Green, D. S. Gerhard, G. Temple, D. Haussler, and M. R. Brent. 2007. “Targeted discovery of novel human exons by comparative genomics.” Genome Research. Cold Spring Harbor Laboratory Press; ISSN 1088-9051/07; www.genome.org
2. Cardno, A. G., Rijsdijk, F. V., Sham, P. C., Murray, R. M. & McGuffin, P. “A Twin Study of Genetic Relationships Between Psychotic Symptoms.” 2002. Am. J. Psychiatry 159, 539-545
3. Epinat-Le Signor, C., S. Dousse, J. Lorgeou, J.B. Denis, R. Bonhomme, P. Carolo, and A. Charcosset. 2001. “Interpretation of genotype x environment interactions for early maize hybrids over 12 years.” Crop Sci. 41:663–669
4. Kooter, J.M., Matzke, M.A., and Meyer, P. 1999. “Listening to the silent genes: Transgene silencing, gene regulation and pathogen control.” Trends Plant Sci. 4: 340–347

The problem of pulmonary tuberculosis in pregnancy has attracted the attention of doctors for many years and it is still a current issue. Modern researchers and physicians divide tuberculosis into several independent problems which have difficult solutions. On the one hand, there is the influence of tuberculosis on the course of pregnancy and child delivery as well as on the health of a mother and her child. On the other hand, there is the influence of pregnancy and childbirth, the puerperal period and lactation on the course and progress of tuberculosis.

Research on how pregnancy influences the course of tuberculosis has been carried out for many years. Even in the oldest available documents we can find instructions for “personal precautions” and preventative measures against tuberculosis, as well as thoughts about pregnancy and tuberculosis. In 1400 BC the Law of Manu from ancient India prohibited marriages to girls from families with tuberculosis. In different world religions, including Islam and Christianity, there are special restrictions concerning people who suffer from this illness.

In ancient times Hippocrates and Galen taught that pregnancy has a positive influence on the function of lungs. But the Islamic doctors, Arabian as well as Spanish, of the Cordoba Caliphate considered that the blessed process of pregnancy must not be complicated by pulmonary diseases.

With time European medical science changed its point of view. From the second part of the 17th century until the beginning of the 19th century doctors considered that pregnancy had a bad effect on the course of tuberculosis, but then the situation, for some reason, changed. Doctors began to think that pregnancy had a good influence on lung diseases. They even started to advise girls who were susceptible to tuberculosis to marry. Time passed and doctors began to change their opinion on tuberculosis in pregnancy and the extremes in views became less obvious. This happened due to the introduction of an artificial pneumothorax into the treatment of tuberculosis.

Since then the third period in the understanding of the relationship between pregnancy and tuberculosis has begun. The opinion about the course of tuberculosis in pregnant women has changed due to the successful therapy of tuberculosis with the help of the artificial pneumothorax.

During the gestation period, all the organs and tissues of the entire organism experience an increased load, as they are trying to satisfy both their own needs and that of the developing fetus. These morphological and functional changes do not lead to any pathological state in the mother if she is healthy and her course of pregnancy is normal. If the woman’s organism has been weakened by a chronic immunodeficiency due to poor environmental conditions or if she has a tuberculosis process in her organism, then functional changes and tissue dystrophies can develop in her nervous system which will lead to metabolic disorders. Changes in ergasia caused by pregnancy and connected with changes in higher nervous activity, as well as with endocrine reorganization, can influence the development and the course of the tubercular process.

Before penicillin was discovered, pregnancy usually led to the progression of the disease and in many cases even ended fatally. Nowadays due to the use of effective antituberculous medicines the attitude towards possible pregnancy of women who have active tuberculosis has considerably changed.

Tuberculosis in a pregnant woman usually starts in an acute form; at this stage infiltrative forms of the disease with necrogenic and bacterioexcretion prevail, often combined with exudative pleurisy, trachea, larynx and bronchi lesions.

Frequent consecutive pregnancies have a negative effect on the state of women who suffer from tuberculosis; they weaken the organism and can cause the recrudescence of the tuberculosis process. This is very typical of many families in poor Asian and African countries. More than half of all pregnant women suffering from an active form of tuberculosis experience a progressive iron deficiency anemia during the first three months of pregnancy and in the second trimester of pregnancy this can be observed in almost all patients. Malaria is also widespread in Asian and African countries that are situated to the south of Sahara and are the second reason for iron deficiency anemia.

According to modern views, one of the reasons for the recrudescence of the tubercular process during pregnancy is an irregular or non-systematic treatment of this illness or the absence of any treatment at all. The recrudescence of the process observed in those suffering from destructive pulmonary tuberculosis is caused by the severity of the illness itself when new conditions for the organism occur. In this case, pregnancy begins against the background of an advanced chronic immune deficiency. At the same time, due to the feto-placental complex operation, functional changes in the nervous, respiratory, cardiovascular and urinary systems, as well as hormonal changes, in the organism of a pregnant woman take place.

Moreover, the development of the fetal skeleton requires calcium which is absorbed not only via the blood of the mother, but also from the healed niduses of tuberculosis and as a result, the progression of a specific process can appear.

The reactivation of the tubercular process happens due to a decrease in the responsiveness of the organism and because of an increase in the activity of the reproductive hormones and the loosening of the connective tissues which are physiologically involved in pregnancy. The amount of plasma and extra vascular fluid increases. Due to these changes, a swelling and loosening in the inactive tubercular niduses with the mycobacteria of tuberculosis can appear. And loosening, in its turn, enables a lymphohematogenous spread of mycobacteria.

In addition to these, the delivery of a child leads to a speedy reorganization of all the functions of the organism; lactation and nursing in their turn are combined with an increased loss daily of nutritious matters and a large amount of protein and fats. In case of destructive pulmonary tuberculosis, due to the fact that the diaphragm descends (resulting in the abdominal decompression ceasing to have a therapeutic action of pneumoperitoneum) bronchogenic dissemination appears in the unaffected parts of the lungs.

A specific active process can be observed in women belonging to the high-risk group in connection with tuberculosis. The high-risk group combines women who have recently suffered from tuberculosis (less than one year after treatment), those who have just been operated on for a tuberculosis connected illness (less than one year), women with tuberculosis of different localizations younger than 20 years (for Asia and Africa) and those older than 35 years (for Europe and the USA), those with widespread forms of the tubercular process withstanding its stage, women who have had contact with people discharging bacteria or people suffering from tuberculosis but not discharging bacteria, and also those who have coexisting illnesses (diabetes, chronic nonspecific pulmonary illnesses, problems with kidneys, stomach and duodenum ulcer), and also women who use alcohol, narcotics, those who smoke and lead asocial ways of life. In these cases, the women must be properly examined during the gestation period, including X-rays.

Treatment of tuberculosis during pregnancy

All other conditions being equal, the timely detection of active tuberculosis during pregnancy allows doctors to provide a full course of treatment, allowing the woman to recover and give birth to a healthy child. Untreated active tuberculosis of the mother is much more dangerous for the fetus than anti-tuberculosis chemotherapy.

Special attention must be paid to healthy women who are in contact with bacillary patients. Quite often these women might undergo active tuberculosis for the first time during pregnancy or after the delivery itself.

In the pre-penicillin era the recrudescence of the tubercular process during pregnancy and after the delivery proceeded in an acute form with frank infiltrative changes, a necrogenic process, bloody expectoration and very often a generalization of the process. Nowadays, the clinical outlook for complications and the recrudescence of tuberculosis against the background of pregnancy is less gloomy. It more resembles the toxicosis of pregnancy or respiratory diseases.

While examining a patient, special attention must be paid to chest problems like moist or dry coughs, bloody expectoration, pain in the chest and shortness of breath. If the patient coughs with expectoration for 2 weeks then she must be examined for mycobacteria with the usage of a microscopic technique.

Another syndrome, which is also very important, is a complex of intoxication symptoms (weakness, hidrosis, anorexia, weight loss, long-lasting low grade fever and hyperirritability) which need to be detected to discover the reason for their development. While examining the anamnesis of a pregnant woman it is necessary to learn if she has ever suffered from tuberculosis before, if she has had any possible contacts with infected people, whether there are cases of tuberculosis or concomitant diseases in her family as all of these can be very useful for the verification of tuberculosis.

When active pulmonary tuberculosis is suspected an X-ray examination is necessary. When the chest is in frontal projection, the X-ray exposure of the fetus is 10 times lower than that of its mother (with compulsory use of a protective apron). Examination of the cough expectoration for the presence of tubercular mycobacteria is one of the easiest, most effective and informative diagnostic methods.

Chemotherapy, which destroys the tubercle bacillus that spread in the organism, plays a leading role in the variety of methods for tuberculosis treatment. By reducing the population of bacteria, chemotherapy supports the healing process, the dispersion of inflammatory changes, the closing of caverns, the encapsulation of the remaining loci as well as preventing the development of sclerosis. When the patient suffers from tuberculosis, the healing processes are very slow; the first stage of the recovery process of mycobacteria ceases and only after some months, in the case of a successful treatment of tuberculosis, does the healing process finish.

The necessary treatment of pregnant women who suffer from tuberculosis must start as soon as the diagnosis has been made. Chemotherapy implies taking antibacterial medicines (isoniaside, rifampicin, pyrazinamide, ethambutol, ethionamide and etc.) in different combinations. The choice of this or that combination depends on the stage of the disease as well as on any undesirable reactions to the medicines prescribed.

The treatment of tuberculosis (if there are indications) continues during the entire pregnancy and lactation period. In particular, patients with tuberculosis that has been diagnosed during the pregnancy are in need of treatment. When there is a systematic treatment, up to the moment of delivery and in the puerperal period, positive clinicoradiologic dynamics can be observed regarding the specific inflammation (stoppage of bacterioexcretion, closing of caverns, dispersion of loci, infiltration and exudate). Patients who reject treatment during the process of pregnancy suffer from an advancement of the illness.

Transplacental infection of the fetus with tuberculosis almost never occurs, but the baby can be infected from the mother in the puerperal period. There is also a possibility of contamination during delivery, but this is a rare occurrence.. God truly protects the innocent!

Permission to breast feed must be given by a joint resolution of an obstetrician, a pediatrician, and a specialist of tuberculosis taking into account the state of a woman and the form and the stage of the tubercular process. Overall precautionary measures must be taken (a nonbacterial mask of 5-6 layers covering the nose and the mouth, a kerchief covering the head and thoroughly washed hands).

A bacteriological study of the breast milk of women who suffer from tuberculosis shows that typical mycobacteria rarely vegetates (no more than 0.33%). Human milk has the ability to suppress the development of the mycobacteria of tuberculosis. This must be connected with the rich spectrum of ferments, immunoglobulins, cellular elements, macro-phages, the complement system, interferon and other factors of nonspecific protection which human milk contains.

The contraindications for nursing are as follows: tuberculosis of the lactiferous gland, an acute form of tuberculosis, active pulmonary tuberculosis with bacterioexcretion, active tuberculosis of any organs detected at the end of the pregnancy or after the delivery, and recrudescence of tuberculosis during the pregnancy. Children born to such mothers are immediately isolated after their birth and bottle fed, they are vaccinated and stay in the hospital for 6 weeks if possible (the minimum period for compulsory postvaccinal isolation).

Thus the tubercular process in the lungs, especially an active one, will have a negative influence on pregnancy and delivery. Babies born to such mothers belong to a high-risk group as far as the possibility of neonatal pathology and antenatal death of the fetus are regarded. Women with pulmonary tuberculosis must undergo regular consultations with both an obstetrician-gynecologist and a phthisiologist from the very early stages of their pregnancy. They must also receive special treatment until all the signs of active tuberculosis have been eliminated.

With the full extent of its use not being understood at the time of its establishment, the project emerged mainly with the pharmaceutical mission to predict, detect, treat, and cure diseases that were caused by genetic anomalies by identifying the genetic information in the human organism.

The desire for such a project was something akin to, or even beyond, the desire to climb Mount Everest, for it aimed to find out something that was unknown at the time. In such fields of biology as cell biology, immunology, and neurology the specialists need genetic information from human organism. The genetic information that an individual organism inherits from its parents can open a door to answer the questions of how an individual develops, how long an individual will live, or how the various species on Earth have lived over many generations.

New developments followed one upon another with the emergence of the Human Genome Project. When the famous Scottish sheep, Dolly, was cloned in 1997, it still seemed to be theoretically impossible to clone a human being. American scientists cloned an ape named Tetra which shared 98 per cent of the same genetic information as human beings. Soon after this, the scientists began to suggest that that all that remained to be cloned was humans.

Dr. Richard Nicholson, the editor of the Bulletin of Medical Ethics, noted that there is no danger in cloning humans, as long as the techniques of doing so are kept under control. If a dictator, however, were to get hold of this information, they would be able to produce an army of genotypically identical soldiers.

The most exciting scientific study of recent years of the Genome Project is that it is trying to develop a complete gene map of an individual organism. According to scientists, a human body has between thirty thousand and fifty thousand genes. All genetic features identifying an individual are found in the gene sequences of the DNA molecules. Eye color, character traits, IQ, and all the illnesses a person may possibly develop are all hidden in the genes. The genome carries all the hereditary features that determine all of life’s diversity, determining whether an organism is human or another species, or ape; all living things have their own genomes. The human genome, which is the full complement of genetic material, and which resembles large tablets recording the history of ancient civilizations, is distributed among 23 sets of chromosomes. It is comprised of approximately three billion letters and is the biological record of our destiny.

Ethical, Legal, and Social Issues

In H. G. Wells’ classic novel The Island of Dr. Moreau (1896), Dr. Moreau conducts hybrid experiments on animals that result in twisted masses of flesh, half-man, half-animal. When the European Patent Office allowed the Australian company Amrad to obtain new embryos by combining human and animal cells, this led to a revival of genetic fears, more than a hundred years after the story of Dr Moreau was published. Not surprisingly, this event alarmed several civilian organizations, including Greenpeace. In a press statement made in Hamburg, Greenpeace drew attention to the fact that we might face “dangerous creatures” in the future that would be created from such techniques. Probably one of the most disturbing facts was that the patent did not disclose how these creatures were to be used. Greenpeace voiced opposition to this for the following reason: “A patent grants its owner the exclusive control over his/her invention. Therefore, patents on life fundamentally change our perception and understanding of living nature and our relationship towards it. Living organisms, which have been ‘created’ by industry and which can be patented cannot have a value of their own, since they are only considered an invention of human beings. Thus they can be exploited without any ethical concerns.”

According to the patent, the embryonic stem cells derived from humans, mice, birds, sheep, pigs, cattle, goats, or fish could be used. The patent covers a “method of producing a non-human chimeric animal” by mixing human and animal embryonic cells: human stem cells are integrated into animal embryos. As a result, the created chimeras are non-human, but they may contain human organs, body parts, nerve cells, and even human genetic codes.

Experts state that the system of producing chimeras is completely different from that of cloning and they drew attention to the risks involved. For example, a virus like the one that caused mad-cow disease could easily pass from one species to another.

The Media Joins the Issue

Thanks to the great interest people have shown in the future of genetic studies, we frequently come across news reports that deal with the topic. However, we would like to note that titles like “the homosexuality gene has been found” or “genetic solution to talkativeness discovered” infuriate genetic scientists. Dr Arnold Munnich says that media aims to raise interest by misinforming the public with subjects like “obesity gene” or “laziness gene”; they merely oversimplify the issue. Dr Munnich emphasizes that a gene means nothing by itself.

The Danger of Abuse

The researches who have worked toward improving gene technology have performed some good for humanity; this is without a doubt. However, there is the risk of abuse. The discoveries in this field may be worth a great deal financially; when we add the rivalry between companies and countries, it seems highly likely that legal bans and ethical rules will be ignored. Some people even object to all kinds of genetic research, not only their abuse. They say that the abuse of seemingly useful genetic technology practices in the future is possible, as has happened in other fields of technology; nuclear researches and laser technology also used to be innocent studies at the very beginning. But we cannot object to the use of electricity just because it is also used for executing people with electric chairs.

Governments and international organizations are quite sensitive to ensure that gene technology will only be used for the good of humanity. There are several international organizations interested in the ethical dimension of the issue. There are certain rules and regulations that establish the fundamental principles that will prevent the abuse of genetic studies, and protect the biodiversity and ecological balance. It is forbidden to carry out research on human cloning and altering human embryos. In the past, dictators like Adolf Hitler attempted to abuse gene technology in this respect. The ruthless Dr Joseph Mengele tried to clone his Fuhrer from the epitel cells he took from him.

Will Confidentiality be Respected?

Another concern brought about by new diagnosis methods and tests is that the principle of patient confidentiality, which has existed for centuries like a secret agreement between doctors and their patients, has begun to be debated, even violated. We usually talk about such “confidentiality” when the information is likely to be harmful for the patient if publicized. From this perspective, the results obtained by genetic tests can be evaluated as such. It is one of the duties of doctors to maintain patient confidentiality. On the other hand, if the relevant data is also likely to harm society, the hospital staff, and those around the patient, then the doctor can face a dilemma.

Some of the possible problems that may be faced due to the mapping of human genome will be that employers could be provided with forehand knowledge about the potential genetic diseases of applicants; they may know whether the person to be employed will be a future financial burden to the company if they carry such genetic risks as cancer or Parkinson’s. In this way new standards of employment will be developed. Even though systematical public surveys do not indicate any significant dangers at hand, it would be nearly impossible to stop rumors. Several people may be denied insurance if they have the genes for a fatal disease. Another may be dismissed from their job for the same reason. In the USA, it is illegal in 39 states to issue insurance policies according to genetic test results, and it is also illegal in 15 states to expel employees according to these. However, employers and insurance agents take advantage of the gaps in relevant laws and they secretly make use of genetic tests. According to research carried out in 1999, 30% of medium-sized or small businesses use such tests to promote and dismiss their employees.

Psychologically, it does not seem likely that people would consent to their status being determined by genetic tests. Would you really like to face your genetic disadvantages? A survey made with cooperation of Time magazine and CNN revealed that half of the participants did not want to know.

The Fate of an Unborn Baby

Deciphering the book of life unfortunately brings along ethical problems. The discovery of our genetic codes can also lead to other humans controlling the future of the human race. The critical question is “Can scientists produce human beings with the desired physical and mental qualities?” If so, genomic science may enable biologists to prepare a list of spare parts, parents may “order” a baby, and as altering our children or ourselves gets easier, we may be less tolerant against those who have not been altered. Lori Andrews of Kent University wonders if we were to be informed of mental defects, obesity, shortness or other undesired characteristics beforehand, whether the parents of those babies would still allow them to be born into a society that scorns such qualities. Even now, it is not uncommon to see some doctors and nurses criticize the parents of babies who are born with pre-detectable defects. If we assume that all parents have “ordered” babies, God knows what kind of a world we will have.

What Should the Aim of Such Practices Be?

Genetic studies should aim to prevent or treat illnesses, not to “enhance” genes. The opportunities offered by genetics should not be a mass elimination medium used by employers or a mechanism of spotting potential criminals in the hands of oppressive regimes. The Almighty One Who has been running the order of our universe so perfectly has granted us some keys to its mysteries. Why should we not do our best and use them for the good of humanity?

References

• Sasson, A., Biotechnologies in Developing Countries: Present end Future, UNESCO Publishing, Paris: 1993.
• McKusick, V.A., “First South-North Human Genome Conference”, Genomics 14, 1121-1123 (1992).
• Barnhart, B. J., “The department of energy (DOE) human genome initiative,” Genomics 5: 657-60,(1989).
• Ferguson-Smith, M. A., “European Approach to the Gene Project,” The Taseb J. 5:61-5 (1991).
• Malakoff, D., Service, R.F., Science, 16 Feb. 2001.
• Dulbecco, R., “The Italian genome project,” Genomics 9:404-5, (1991).
• McKusick, V. A., “Mapping and Sequencing the Human Genome,” J. Med. 320:910-15, New England: 1989.
• Murray, R.K. et al, Harper’s Biochemistry, Appleton & Lange, 1993.
• Neyzi, O., Ertugrul, T., Pediatri, Nobel T›p Kitabevi, Vol. II, Istanbul: 1993.
• Harrison’s Principles of Internal Medicine, International Edition.
• Nature Medicine, Vol. 7, No.4, Apr. 2001.
• Science, No.290, 1 Dec. 2000.
• Nature Reviews, Genetics, Jan. 2001.

We know our bodies to be more than just an assembly of organs and each organ is much more than an assembly of specialized cells. So what makes life so precious and awe-inspiring to those who care to stop and think? Most of the time of our life-span, be it hours, days, weeks, months or many years, we are totally oblivious of the immense complexities which operate within us.

Just as fascinating as the why and how of early embryo development (gastrulation) is the phenomenon of cell death. Even as cells are proliferating and differentiating in the various stages of gastrulation, many individual cells must be sacrificed for the benefit of the whole. Do not be alarmed at this expression – thousands and millions of our cells die and some may be replaced many times during the average adult life. The most common example is that of our skin cells. Up to 90% of household dust consists of dead skin cells. Old blood cells in circulation are constantly removed by the liver and replaced by new cells manufactured in our bone marrow. But there are more subtle forms of cell death of which we were, until recently, quite ignorant.

All cells in multi-cellular organisms are capable of committing suicide in response to signals from other cells. Sometimes the absence of a given signal heralds the onset of programmed cell death. Two distinct forms of cell death have been identified by researchers in the field [1]. These are known as 1) necrotic cell death and 2) apoptotic cell death. The first is quite a common and well-observed phenomenon which occurs when cells die from severe and sudden injury. Also known as accidental death, examples of such events leading to necrosis are ischaemia, sustained hypothermia, and physical or chemical trauma. In necrosis the mitochondria (required for producing energy in cells) undergo changes which are visible as changes in their shape. The plasma membrane is often the major site of damage and homeostatic control of the cell’s environment is lost. As a result the cell first swells then ruptures, spilling its contents into the surrounding tissue space. This provokes an inflammatory response namely the attraction of patrolling white blood cells which clear away the debris by engulfing and ingesting it. Thus the process of repair can begin. Apoptosis, on the other hand, exhibits a completely different set of morphological features and the process is much more refined. It is not observed during accidental cell death but appears to be an integrated part of the normal process of tissue regulation. Let us take a closer look at this fascinating phenomenon and see what it involves:

The main characteristic associated with apoptosis is the distinct set of morphological events which take place (see Figure 1). Whereas necrotic cell death results in cell lysis and a consequent inflammatory response, apoptotic cell death is very much the opposite where the size of the cell decreases (rather than increasing through swelling) and there is no spillage of cell material.

Figure 1:

a) Normal cell with sparse cytoplasm and heterogeneous chromatin;

b) The start of Apoptosis: sonic loss of cell volume, cytoplasmic organelles are tightly packed and the chromatin condenses;

c) ‘Zeiosis’ i.e. ruffling of plasma membrane;

d) Chromatin collapses into crescents along the nuclear envelope, very condensed in appearance;

e) Nucleus collapses into central black hole;

f) Fragmentation of the collapsed nuclear material into small spheres;

g) Formation of apoptotic bodies.

It has been proposed that the sixth step of apoptosis makes it a foolproof method of disposing of cells since once destroyed, DNA (which is the vital blueprint of cells) cannot be re-assembled. This ensures irreversible removal of defective / harmful DNA material so that none of them can resist apoptotic death once it has been initiated.

Why Die? – the functional roles of Apoptosis:

Apoptotic cell death can occur in a number of physiologically acceptable situations. Some well- observed, but still poorly understood, examples are cited below:

a) tissue re-modeling during embryonic development As mentioned earlier, whilst new cells are being generated a significant number of early cells die to make room for others to form the sophisticated multi-cellular organisms that we are: e.g. cells which form the ‘webs’ between the fingers and toes in the early stages of development, thus leaving them free to move.

b) migration of cells into abnormal locations. Tumour cells are prime examples where such migrated cells can cause damage to other cell-functions and are thus, best removed promptly and discreetly.

c) cells which are no longer functional. To refer to a non-human example, the metamorphosis of tadpole to adult frog includes, amongst other changes, the loss of the tail.

d) removal of cells produced in excess – developing sympathetic neurones are always produced in higher numbers than required. These then compete for nerve-growth-factor released by their target cells. In this way the number of neurones innervating target cells is matched to the number of target cells available through competition for the growth-factor.

e) specialized cells need to be selected for specific functions. In the thymocytes of developing embryos, antigen receptors on T-cells are selected for, i.e. T-cell lymphocytes expressing the correct type of receptors are retained whilst those whose receptors have too high or too low affinity for antigens die through apoptosis. If the receptor affinity is too high it will attack the cells of the body, those with insufficient affinity are of no use and thus, meet the same end. As a result the body accumulates a repertoire of lymphocytes which are useful in the fight against foreign matter yet do not harm the self.

Examples a), b) and c) are in opposition to the ‘Theory of Evolution’ i.e. there is no outright competition for survival. The concept of ‘survival of the fittest’ does not apply

Take another striking example: the flatworm, Caernabhditis elegans (C.elegans), has a short lifespan and a simple body plan. It has been well studied and of its developmental stages leading to the adult, the following has been noted: of the 1,090 somatic cells (i.e. all cells except the sex cells) 131 die during development, each with morphological features resembling apoptosis. Each of the 131 cells dies at a precise time and the timing of their death is absolutely reproducible i.e. every one of these 131 cells dies at a time identical in every C.elegans. This is defined as being true programmed cell death by apoptosis. Once again there is no competition between the cells to outlive their counterparts.

Because of its simple body plan it has been possible to map the development of C.elegans in such detail. No doubt, if it were possible for us to do the same for other complex organisms, including ourselves, we would discover greater precision in timing and developmental control. How else do single fertilized eggs become the perfectly-formed animals or humans that roam the wide world?

Unable to grapple with the idea that all living cells in multi-cellular organisms are capable of, and are apparently programmed to sacrifice themselves for the sake of the whole community i.e. the organism itself, Martin Raff [2] has put forward his ‘extreme view’. He claims that cell-suicide occurs by default. In other words, cells are programmed to die and only live if they receive appropriate signals from other cells. As yet, there is insufficient evidence for this ‘extreme view’, a term used by Raff himself to describe his theory. Consequently, his research is aimed at finding evidence of ‘never-lasting life’. This implies that living cells sustain each other and therefore, also implies that organisms are self-sustaining entities. It also incorporates the denial of the need for any external life-giving source. Inevitably, the whole concept is blatantly opposed to the belief in the existence of a Creator and Sustainer of the Worlds.

How did these cells acquire the intelligence behind altruism i.e. this selfless death for the benefit of the whole? One is compelled to ask whether individual cells really comprehend the greatness of their death in relation to the survival of the whole organism? Do they have the far-sighted knowledge which is necessary for such noble suicide or are they just obeying orders from a much greater source of wisdom and knowledge i.e. the All-Knowing Creator of the whole organism and the self-sacrificing cells? Whether it be caused by the presence or absence of sophisticated chemical signals ‘natural programmed cell-death’ is truly an event to marvel at. Because of the absence of inflammation, large-scale ‘normal’ cell death causes no disturbance in the body of the organism and is one of the reasons why it received less attention from researchers than necrosis. Whatever the cellular mechanisms of apoptosis, the ability to die without any fuss is a manifestation of complete submission (meaning of the Arabic word islam) to their final destiny.

Even as you read this, extensive research into apoptosis is being carried out. Without cell death or even death of any living thing, life on earth would be uncontrolled, lacking in organization and endless! The ultimate catastrophe, indeed. Greater understanding of the how and why of cell death may enable us to intervene in preventing or initiating the process. Researchers are most intent on preventing cell death. It seems that their final dream would be to defy death itself. Future revelations of details about the how and why of cell death can only add to our awe before the All-Knowing, the All-Wise, the Creator of all realms within and beyond our comprehension.

References 

1 KERR, J. F. R., WYLLIE, A. H. & CURRIE, A.R. (1972) British Journal of Cancer 26, pp.239-57.

2 RAFF, M. C., (1992) Nature 356, pp.397-9 FURTHER READING:

a) COHEN, J. J. (1993) Immunology Today 14, pp.126-30.

b) COLLINS, M. K. L. & RIVAS, A. L. (1993) TIBS 78, pp. 307-8

c) BUTTKE, T. M. & SANDSTROM, P. A. (1994) Immunology Today 15, (1), pp.7-103.

d) HOCKENBERRY, (1993) Cell 75, pp.241-51.

Genetics is commonly taken to refer to a part of biology that concerns itself with the study of the transmission of hereditary characters. This fascinating science would have remained quite benign if this was all that it was. However, recombinant DNA technology with all the power it offers for biological control has changed all that. By making it possible to manipulate the reproductive potential of an organism, modern genetics has the power to alter the course of development of living organisms. Life can be changed, for good or ill; it can be enhanced or retarded or mutilated. Moreover, whatever molecular genetics can do to the biological world can in principle, be done to human beings. Molecular genetics poses a grave threat to our notions of human life, its intent and its meanings.

In his book Responsible Science (1986), Robert Nelson wrote: 

The challenge of molecular biology to traditional humanistic and religious concepts of human life needs to be taken very seriously. Not only the nature of life, but its purpose and worth are called into question by the rapidly growing knowledge of DNA and cellular development. If the human organism can ostensibly be reduced to an assortment of proteins and amino acids, hardly distinguishable at molecular levels from those of other organisms, where is the distinctiveness of human life to he found? And if found, how explained?

Biology, especially in the form of using genetics and evolution to explain social phenomena, has become a reductionist exercise. Reductionism means trying to explain the properties of complex wholes-molecules, say or societies-in terms of the units of which those wholes are composed. Scientists who are reductionists would argue, for example that the properties of a protein molecule could be uniquely determined and predicted in terms of the properties of the electrons, protons, etc., of which it atoms are composed. In a similar way, they could (and some do) argue that the properties of a human society are no more than the sum of the behaviours and tendencies of the individual humans of which that society is composed.

Genetics and evolution, as indicated above, have been used to explain social phenomena. This is the area of science called sociobiology. It is a discipline that passes moral judgement on many social issues because it presents biology as the human fate, an inescapable reality of nature. Since it is natural, the implication is that it is immutable.

Sociobiologists equate the social with the biological and maintain that differences of class, race, colour, gender and even economic status originate in individual biology. This type of thinking could lead to dangerous conclusions of a sort most of us would regard as immoral and unethical. It can lead, for instance, to the belief that some races are born ‘inferior’ to others; that women are inferior’ to men; IQ (Intelligence Quotient) is genetically determined; that social inequalities (wealth and poverty) are biological in origin. The big problem with this is that political leaders could use such arguments to assert that the current social order must prevail because it is the law of nature.

Sociobiology reached its peak when some biologists claimed to have discovered absolute evidence for genetic determinants of human behaviour. In his popular book The Selfish Gene (1976), Richard Dawkins wrote:

We, and all other animals, are machines created by our genes. Like successful Chicago gangsters, our genes have survived, in some cases for millions of years, in a highly competitive world. This entitles us to expect certain qualities in our genes. I shall argue that a predominant quality to be expected in a successful gene is ruthless selfishness… Much as we might wish to believe otherwise, universal love and the welfare of the species as a whole are concepts which simply do not make evolutionary sense … If you wish … to build a society in which individuals cooperate generously towards a common good; you can expect little help from biological nature.

The selfish gene thus operates to enhance its own selfish interests. The theory is based on the belief that genetic differences lead to behavioural differences, and that organisms are hosts to genes rather than the other way round. This provides the basis, as sociobiologists themselves claim, for the systematic study of the biological basis of all forms of social behavior, including sexual and parental behaviour, in all, kinds of organisms, including humans.

More and more human attributes are being subjected to a biological explanation. The Islamic view of human nature, however, does not consider biology as an inevitability. Human morality is the most important determinant, encompassing the spiritual dimension beautifully: The most honoured among you in the sight of God is the most righteous among you. And God has full knowledge and is well acquainted [with all things]. (Hujurat, 49.13)

We give it life and We bring forth from it grain, so from it they eat.(36.33)

There are a number of points in this verse which can bear explication from a scientific view-point.

1-Use of the expression dead ‘earth’ (rather than dead ‘soil’), indicates that the soil of the whole earth is implied.

2- One meaning of ‘for them is a sign’ is Divine portent. The occurrence of the phrase at the outset of the verse alerts us to the fact that the verse will encourage us to understand a very important family of natural phenomena.

3-We are informed that in its initial state, the earth was devoid of life. In this way, the lifelines of the earth when it was first created is expressed as a geological fact.

4-We learn that the soil, which appears dead is actually alive. Even this one observation affirms the miracle of wisdom contained in the verse. For it is only a hundred years since it was discovered that there are organisms in the soil, while it is scarcely forty years since the discovery that 80% of soil consists of bacteria, and thus is a community of living organisms.

5-‘We quickened it and brought forth from it habba.’ According to the latter part of the verse, habba signifies seeds of a vegetable nature or, specifically in this context, grain. However, habba in general denotes small, uniform particles, and we shall discuss the verse’s inner meaning also from this angle.

6-The verse declares that life is transferred via the soil to plants and thence to us, a chain of events singularly important from the standpoint of biochemistry. While the verse uses the word habba in the general sense, particularly mentioned is what is eaten from it in the form of vegetable food.

In order to comprehend this verse in all its subtleties, one needs first an up-dated grasp of the concepts of life and vitality as scientists now understand them. For the concept of vitality has changed greatly in recent years, and come closer to its inner truth. The biological knowledge of the past has been left far behind.

Life is a mathematical programme encoded in a giant chemical molecule. The Qur’an indicated this reality, discovered only in recent years, fourteen centuries ago in the statement (80.19): We created him from a drop of liquid; we shaped and programmed him.

Allah first created bacteria which fix nitrogen in the soil. In chemical terms, these bacteria are laboratories of ‘synthesizers’; that is, they take nitrogen from the air and prepare compounds with negative valences. They reduce nitrogen by a method that we still cannot fathom, and convert it into a form in which it can combine with hydrogen. They require water and rain for this purpose–which is why we observe that life springs from the soil when it rains.

A second type of bacteria in the soil is what might be called the ‘analyzers’ after their particular role in the Divine programme. They break down whatever falls to the ground and so prepare the way for the ‘synthesizers’. Excluding water, the greatest part of any quantity of soil is found to be composed of microbes.

In botanic terms, soil is regarded as a totally living structure, and so it has been since the origin of life on earth, which is to say, in a modern scientific idiom, a truth that is directly expressed in the Qur’an.

It is in order to sow confusion in people’s minds that atheists distort the established facts about the emergence of various organisms on this planet. They maintain that all organisms have evolved in a gradual process (with some abrupt leaps) from a single cell, randomly becoming the various plant and animal species we see around us or discover in fossil records. This is the so-called ‘theory of evolution’. But the secret of ‘the Living’, giving life to the soil, as also to plants forming from seeds after the soil has come to life, is diametrically opposed to this theory. What is expressed in the Qur’an can only be the truth while any notion opposing it can only be falsehood.

The theory of evolution was propounded toward the end of the 19th century. As I have just explained, organisms were thought at that time to embody different chemical structures, the smaller organisms having a simpler chemical composition, while a more complex organism had a more complex composition. The mathematical programme within cells was wholly unknown.

An evolution of the most primitive structures could, of course, be conceived but as soon as we wish to understand organisms, distinct living entities, however simple, the assumptions of evolution simply break down. For, as we now know, the differences in the emergence of different organisms resides in the mathematical programming to which they operate. The perfection of these very diverse programmes is not open to question; nor is it possible to speak of evolution among them, as one being somehow ‘later’ than another. Compare, for example, a bile-producing cell in the body and a nitrogen-fixing bacterium of simpler countenance in the soil. Which of them performs the more difficult task? It is not hard to decide the question: chemically, binding nitrogen to hydrogen is undoubtedly the harder task. Again, bacteria are thought to be the most developed sorts of cell, not those which carry and enable human intelligence. While DDT, the notorious insecticide, was wreaking havoc with the environment, the common house-fly, a somewhat despised and lowly creature, developed such a prescription in the fluid of its nerve cells that it proved impossible to exterminate another fly thereafter using DDT. A neuron in the human brain could not produce this prescription and preventative if it were to labor at the task for a thousand years.

Well, now, which cell is the later development? Which is the primitive form and which the more evolved? Of course, man is the most perfect of organisms, but he cannot do anything outside of the programme within which all his life is contained, and, as the Qur’an says, can be defeated even by a fly.

Thus, once the concept of life is examined in depth, it can easily be seen that the theory of evolution is a human fiction. Fish with luminous organs were swimming at the bottom of the ocean millions of years ago, just as, at that time, bats equipped with radar were flying in the dark, whereas we are only now discovering these facts and starting to put them to use.

A most important question concerning life in modern biology is how skills are handed down. Grant that an organism inherits its entire constitution from its parents, how does it acquire the special skills it needs in order to continue its life? How does it learn, for example how to build nests or defend itself against other creatures? If a living organism may be likened to a mathematical computer programme, how is the learnt part of that programme transferred from generation to generation without slip-ups or distortions?

In seeking an answer to this question, biology has accepted that a certain programme called the genetic code is passed on. This explanation is for coarse, external similarities between cells, but not for embryonic cells or cells of the bone marrow.

Allah has said (41:47): Without divine science no woman conceives, no fruit separates from its rind. In scientific idiom, the meaning of this verse is: Every cell is given its mathematical programme in a continuous fashion.

Taking all the verses quoted above together, we begin to understand that vitality has two district aspects: the molecules that form the organism are its physical components, while the mathematical programme imposed on this structure is akin to the programming of a computer. This programme is, in a sense the individual organism’s individual destiny of fate. Ya Sin, verse 12 tells us that each creature is recorded In the Guarded Tablet in terms of its most minutely individual qualities (36.12) This declaration is an invariant law for life in general. Every living entity–a weed or a flower cell or a gall bladder cell will each perform what encoded is (inscribed) in its cellular computer, within the compass of Divine Omniscience, by the Divine Will.

The principle of life’s continuation is stated in the second part of the verse we are trying to interpret. After initiating life in the soil, and introducing to it organic materials indispensable for life, Allah created plants from it which in turn carry the basic structural materials necessary for other organisms.

The ‘grain’ mentioned in the verse can refer to the seeds of the plant but also to the constituents of a complete cell. All the organic nutrients for sustaining the life of organisms exist in grain. This fact was not accepted in earlier times: it was not known or accepted that, grain contains carbohydrates, protein, fats, vitamins and minerals all at the same time; on the contrary, it was thought that food derived from wheat and similar plants could not provide sufficient nutrition. But the habba (grain) actually represents all of the basic materials necessary for life.

That fact underlines another, namely that plant and animal cells have common building blocks. The difference lies in their programme or destines. One of the most important inner meanings of the verse is that the soil vitalized by Allah also serves as an incubator for organisms. This secret is imparted especially in the second part of the verse.

A fertilized egg develops in three basic ways: 1. beneath the earth (all plants); 2. inside an egg shell (most animals); or 3. in the mother’s womb (mammals).

From the scientific point of view, all three kinds of development serve the same purpose of instilling life into the organism. The fertilized egg needs a period of incubation and development in order to form the new organism. Biologically, this process is one in which the cells of the new organism form. The seed needs protection during this period, and must draw particular chemicals and ions (as yet unidentified) from its environment. In this way, it will be born into life as programmed. In this verse, Allah has emphasized that it is He who has given this characteristic to the soil. Taking only this property of the soil as an example, the vivification of grain is demonstrated.

Actually, this feature of the soil also provides an important insight into the nature of Judgement Day. When the command for resurrection is issued on the Day of Judgement– and this, too, is a mathematical programme–the secret of the verse will be revealed once again, and the dead will be restored to life in that instant.

The enlivening of the soil by Allah is no ordinary event, but a most profound wonder of biology; what is more extraordinary is the way that all different sorts of fruits and vegetables are presented to us from the same soil

This verse may also be regarded as bearing in two respects on the wisdom of Adam’s creation from soil. The Qur’an declares that Adam was created from soil with the texture of mud. We shall investigate that verse in detail in the future. In the meantime, the important thing to note is that Allah does give to the soil something from the secret of His Divine Name, the Living. It can be clearly seen from the expression comprising the two sentences of the verse that Allah has bestowed both life and vitality on the soil, and has made it the vehicle for propagation of other life forms (the secret of bringing forth grain).

Since verse 32 of the same chapter tells of the resurrection on Judgement Day, the verse we are considering points to a connection between the resurrection at the Judgement and the secret of life in the soil.

We have learned many things about soil biology in recent years. I would like to summarize this information also from the standpoint of the resurrection.

As mentioned earlier, all the preconditions necessary for the formation of an organism from a seed are present in soil. That is, the soil conveys a fertilized organism to life, just like the mother’s womb. Both the fertilized egg and the seed are quite similar in that they both represent a genetic code ready to reproduce. This genetic code is the life and character programme of the organism to be formed. (These genetic codes are a millionth of one centimeter in size–if, for curiosity’s sake, you were able to amass the genetic codes of all the human beings who have ever lived, they would not fill a drinking glass.)

It should not be doubted that, had Allah willed, He would have developed the human seed in the soil as we sell. Indeed, when Allah declares in the verse that the way in which We quicken the dead earth is a sign, He enables an understanding of an issue that science is hardly beginning to catch up with. The verse stresses how deeply the resurrections promised at the Judgement conforms with the logic of biology. The scientific conclusions to be drawn from the biological facts given in the verse may be summarized in three points:

1-The enlivening of the soil by Allah is no ordinary event, but a most profound wonder of biology. The chain of happenings we call life stems from the secret of the Living in the soil.

2-The Day of Judgement is also closely related to the secret of the Living. Whoever doubts the Judgement will find that his doubts are baseless if he contemplates the wisdom of Allah’s bestowing life on the soil together with the secret of living.

3-Life is, first and foremost, a preordained mathematical programme. The division of organisms into ‘primitive’ or ‘developed’ is based on quite arbitrary judgements. Every organism is the representative of a perfect programme. For this, as well as for other reasons, the theory of evolution should be regarded as fundamentally flawed, if not radically false.