The DNA Molecule's Miraculous Structure
In discussing the chemical structure of the DNA molecule, our objective is not simply to provide the kind of information you can find in a great many books on biology, but to show the details in human creation and the extremely sensitive order on which our existence depends–and thus, to properly appreciate our Lord's greatness and His mercy upon us.
Some people prefer to remain far removed from technical details and don't want to tire their minds with them. But they reflect that same superficial perspective in their analyses, comments and statements. In fact, there is sublime wisdom in every detail of creation, and each of those details has been created for a specific purpose. In one verse of the Qur'an our Lord tells us that:
We did not create the heavens and Earth and everything between them, except with truth. The Hour is certainly coming, so turn away graciously. Your Lord, He is the Creator, the All-Knowing. (Surat al-Hijr, 85-86)
Let's examine some of the details in the creation of the DNA in the trillions of cells inside every one of the billions of people on Earth.
Chemical Structure of the DNA Helix
The giant molecule of DNA (deoxyribonucleic acid) that plays a role in all the cell's vital functions consists of carbon, hydrogen, oxygen, nitrogen and phosphate atoms. There are billions of these atoms in a single human DNA molecule,14 all arranged in a manner particular to that individual.
DNA is an acronym of the words deoxyribo, nucleic and acid that express the molecule's chemical structure. This molecule in the nucleus of every human cell consists of nucleic acid arranged in a helix shape like a miniature sphere just 5 microns in diameter.15 (One micron equals one thousandth of a millimeter.) Nucleic acids are exceedingly important compounds, despite making up only 2% of our bodies. The basic structural units of nucleic acids are nucleotides. Some 6 billion nucleotides combine in the double helix that gives rise to DNA.16
The DNA molecule's structure resembles a spiral staircase, and its architectural regularity amazes scientists. The sides of the staircase, made up of various sugars and phosphates, represent the DNA molecule's dual backbones. The steps, on the other hand, consist of pairs of four conjoined chemical substances known as bases: adenine, thymine, cytosine and guanine. Bases are molecules consisting of between 12 and 16 atoms including carbon, oxygen, hydrogen and nitrogen.17 These chemicals are also specially arranged on the DNA spiral. Only two combinations of arrangements are possible: adenine (A) always bonds to thymine (T), and cytosine (C) always bonds to guanine (G).18
Scientists have established the special sequence in which the atoms making up DNA give rise to nucleotides. But knowing the structure of the building blocks of life is not the same thing as producing them. Indeed, although the correct materials–atoms and the technology to combine them–are available to scientists, they are utterly incapable of making a living DNA molecule. In the Qur'an our Lord reveals that:
It is He Who gives life and causes to die. When He decides on something, He just says to it, "Be!" and it is. (Surah Ghafir, 68)
Your deity is Allah alone, there is no deity but Him. He encompasses all things in His knowledge'. (Surah Ta Ha, 98)
A special creation is evident in the arrangements of the atoms. Every nucleotide contains some 34 atoms. Since there are 6 billion nucleotides in DNA, 204 billion atoms (34 times 6,000,000,000) need to combine chemically to form a single DNA molecule.19 Were you able to process one atom a second and worked eight hours a day for 350 days a year, it would still take you longer than 20,000 years to produce a single DNA molecule.20 Since this is beyond the capacity of even rational human beings, can anyone imagine that the DNA molecule came into existence by chance? Such a thing is of course out of the question. In addition, bear in mind that in the absence of DNA molecules, living things could not exist. Indeed, the slightest error in DNA's structure gives rise to very serious consequences, as the well-known science writer Richard Milton describes:
Every base sequence in the DNA strip–the arrangement of the nucleotides adenine, thymine, cytosine and guanine in the cell nucleus–constitutes a genetic text containing information needed for the building of essential proteins. From that point of view, it is noteworthy that DNA maintains its regular structure on the one hand while on the other having an arrangement that permits information diversity.
The DNA Strip is Wound around Bobbins
A single DNA strip in human cells consists of around 3 billion base pairs and is approximately 2 meters long. Both chains of that length need to be reduced in size to dimensions invisible to the eye. Similarly to the way in which a long thread is wound around a reel, the DNA is packaged and installed in the nucleus through a similar cellular mechanism. The DNA strip is packaged by being wound around nucleosomes, which give rise to chromosomes. The job of the nucleosomes is undertaken by proteins known as histones.
There is a 15-turn section of the DNA spiral in one nucleosome; and this is the length of 150 nucleotides.22 This 15-turn section is wound twice around a protein nucleus, made up of eight histones containing a large number of positively charged amino acids. These perfectly complement the negatively charged phosphates on the DNA. When information written anywhere on the DNA is needed for protein production, the nucleosome opens and the DNA strip is released for "reading." After this, the DNA winds back around the histones, protected from the damaging effects of the molecules around it, until the next time need arises. Genetic data require not just content, but also a sensitive order in their structure and in the features of the surrounding environment.
This order is just one of the works of our Almighty Lord, Creator of the Earth and sky. In one verse, we are told that:
... My Lord is kind to anyone He wills. He is indeed All-Knowing and All-Wise. (Surah Yusuf, 100)
Genes: Data Packages
A single cell nucleus, invisible to our eyes, contains a DNA strip that is 4 meters (13.12 feet) long, packaged inside the nucleus in the form of groups known as "chromosomes" The nuclei of the cells in your body contain a total of 23 chromosome pairs. When chromosomes are magnified under an electron microscope, the DNA molecule inside these chromosomes are seen to be compressed in a spiral form. Despite occupying a very small volume, this packaging system possesses a stunning data-storage capacity, as you'll see in a later chapter.
DNA strips contain all the information required to form proteins of all kinds–enzymes, molecular motors, hormones and other building blocks.23 The information encoded in the DNA molecule determines the symmetrical formation of the eyes and ears, the pumping of blood by the heart, the transportation of oxygen to the cells via that blood, the gastric acid that breaks down foodstuffs, and all the body's other physical features. There are around eighty thousand of these kinds of information packets, known as genes, in the human body.24
If the total amount of genetic information–the genome, in other words–is compared to a library, every book in that library represents a chromosome, and the chapters in the books are genes. Genes are rather like the headings in a giant encyclopedia, containing a detailed blueprint of a human being's biologic characteristics.25
The chromosomes passed on by way of inheritance are determined by the different arrangements of the four chemical bases constituting the DNA steps. Thousands of these steps, or base pairs, constitute a single gene. James Watson, one of the co-discoverers of DNA's structure, notes that base sequences are the source of the differences in genes:
From these four base sequences, Allah has created billions of different human beings and keeps creating. Thanks to the flawless order that Allah created in DNA, human beings emerge with a detailed and complex structure and the rich characteristics they possess. In verse 45 of Surat an-Nur it is revealed that:
… Allah creates whatever He wills. Allah has power over all things. (Surat An-Nur, 45)
DNA is a Stable Molecule
DNA is the most suitable molecule for carrying information. Chemists refer to it being stable, which means the molecule is not easily damaged or dissolved. Scientists engaged in research in the field of molecular biology are well aware of the importance of this stability, because DNA's structure is far more resistant than most biochemicals used in the laboratory. Unlike many biochemicals, it can preserve its stability for months in solution, even at room temperature..27 Prof. Daniel Dennet expresses the stable nature of the bases in DNA:
All shows that the DNA molecule is specially created to contain and conceal information. It is absolutely impossible for all of DNA's properties to have come into existence togather instantaneously, as the result of chance. Each one of these has been consciously brought together at our Almighty Lord's command. In one verse of the Qur'an, Allah reveals that:
... That is Allah, your Lord. The Kingdom is His. Those you call on besides Him have no power over even the smallest speck. (Surah Fatir, 13)
The Astonishing Order in DNA's Spiral Structure
Imagine the coiled cord that leads from a telephone receiver. A long cable has been squeezed into a much shorter distance, but in such a way that it can be extended if necessary. Nobody seeing that cable could possibly imagine that it had assumed that shape by chance, because the place where the cable is used, its purpose and the ease it affords are all signs of an intellect and conscious knowledge.
The DNA in human cells has a similarly spiral shape, but is far more regular, longer and more convoluted. There is enormous wisdom behind the use of this shape. DNA's extraordinary data capacity, which we shall be discussing shortly, and the way it is compressed into a minute space, are made possible thanks to this special form. DNA, which measures 4 meters (13.12 feet) when its spiral is fully extended, takes up no more space than one two millionth of a millimeter, and is hard to see even under an electron microscope.29
DNA is Reminiscent of a Highly Regular Spiral Staircase
The DNA molecule is a coiled helix, consisting of two spirals, rather like a staircase. The coils in the DNS spiral have an exceedingly regular structure. The vertebrae consisting of sugar and phosphate in both DNA chains revolve at an equal distance around a common axis and twist in the same direction, from right to left. Moreover, there is no haphazard sequencing in the steps between the two arms. The bases that make up the rungs form an angle of 90 degrees to the spiral axis, giving the DNA strip its highly regular, staircase-like appearance.
The steps are joined to one another with a special locking system. The four different components of the rungs –adenine, guanine, cytosine and thymine– are of different sizes. The adenine and guanine bases are large, and cytosine and thymine are small molecules. The dimensions of the molecules that will be opposite one another have been determined in such a way as to ensure equal spaces at every point on the spiral staircase. In order for the steps to be always regular, guanine always pairs with cytosine, and adenine with thymine. Thus small bases always being opposite large ones in the DNA molecule means the distance is stable at every point. The result is a regular staircase extending with no interruptions. However, if the base adenine were to be paired with guanine just once, instead of with thymine, it would be impossible for the helix structure to proceed in a regular manner. Any error in the sequence might thus entirely impair the molecule's chemical structure and prevent the data being used, copied and transmitted. This again indicates that the sequence cannot be the work of chance.
The distance between the turns of neighboring base pairs is also stable. This system ensures equidistance between the staircase coils, some 10 base pairs –in other words, 10 steps– form a complete revolution of 360 degrees.30 DNA coils a billion times a second, and the staircase steps twist by performing their spiral movement.31 This action plays a very important role in DNA's performing two vital functions--directing the formation of protein and self-replication. Prof. Werner Gitt, director of the German Federal Institute of Physics and Technology, says this about this special structure:
Importance of the Bonds used in the Building the Spiral
The dual backbones of the long DNA molecule –or the banisters of the staircase– are very strong, made up of consecutive sugar and phosphate molecules. These molecules attach to one another with a special bond known as ester covalent bonds. These are exceptionally strong and it is very difficult to break them. This strength provides protection against harmful factors that might impair genetic information.33 The existence of these bonds makes the DNA molecule resistant and stable even while the DNA molecule is in a single-strand form.
However, there is a risk of damage to the DNA spiral structure as the coils unfold. For that reason, the spiral needs to be strong and stable enough to protect its structure but also elastic enough to be opened up very quickly so that the information can be easily used. In fact, a combination of powerful covalent bonds that protect DNA's basic molecular structure of, and weaker hydrogen bonds that can be broken more quickly, enables the elasticity-solidity problem to be overcome. Since the hydrogen bonds forming between the four opposed nucleotides are not as strong as ester bonds, they can easily be separated with less energy by means of such factors as pH variation (acid-base equilibrium), heat, and pressure. Weak bonds play a very important role in the shaping of the large molecules in an organism, and endow with elasticity the substance they compose. However, no breakage in the bonds ever takes place. Thanks to this distinguishing feature of hydrogen bonds, the information in the DNA molecule can be used whenever required.
The significance of the elasticity in the bonds is that the vital function of protein production is made possible by DNA being copied when cells divide, and that transmission is made possible by the elastic property of the bonds between them. Since the two chains of the DNA molecule are attached to one another only by hydrogen bonds, they can easily be unraveled and separated from one another. They can also, when necessary, recombine and form a new helix structure. No breakage or impairment ever takes place in the nucleotides that constitute the steps of the DNA chain during detachment or separation. While the hydrogen bonds in the center can easily separate from one another, no breakage or stretching ever develops in the long chains at either side, attached by means of covalent bonds. The molecular biologist Michael Denton describes the perfection in the biochemical structure of DNA:
On the one hand, there is a need for a sound and stable structure for the containing of genetic information, while on the other a flexible structure is required for the genes to be read and copied. So the strength of the bond between the two arms that make up the DNA helix has to be just right for it to fulfill its essential functions. And indeed, the DNA helix does have just the right level of strength and elasticity. If the bond between the DNA strips were any stronger, the two arms would stop moving and become fixed. But if the bond were weaker, the molecule would break apart.35 Yet by the will of Allah, the bonds that constitute DNA have the ideal structure to make the helix both highly regular and exceedingly functional.
The Importance of Phosphate in DNA
Phosphates keep together the nucleotide bases on DNA, because the DNA helix functions in an environment containing water, and water breaks down the bonds between phosphates and sugars. Thus it is both advantageous and essential that the phosphate groups in DNA be negatively charged. That negative charge eliminates the danger of the DNA being broken down in the watery environment surrounding it.
What compounds, other than phosphates, could establish a chemical bond and still manage to remain negatively charged? There are various possibilities. Yet none of these can form genetic information in the way that phosphate does. Silicic acid and arsenic esters break down rapidly in water. Although citric acid dissolves more slowly in water, it lacks the stability to maintain the molecule's geometry.36
Therefore, if phosphate did not have its own unique properties, the DNA's double helix could not form. No self-replication biochemical system could be established, and life would be impossible. The well-known professor of chemistry Frank Henry Westheimer says this: "All of these conditions are met by phosphoric acid and no other alternative is obvious."37 This situation and all the other details we have examined so far clearly show that our Lord has created the DNA molecule with miraculous properties. In one verse of the Qur'an, it is revealed that:
He knows what is in front of them and behind them. But their knowledge does not encompass Him. (Surah Ta Ha, 110)
14. Walter L. Starkey, The Cambrian Explosion, WLS Publishing, Ohio, 1999, p. 155.
15. Michael J. Denton, Nature's Destiny, Free Press, New York, 1998, p. 149.
16. Walter L. Starkey, The Cambrian Explosion, p. 41.
17. Lee M. Spetner, Not By Chance, Shattering The Modern Theory of Evolution, The Judaica Press Inc., 1997, p. 213.
18. The Incredible Machine, National Geographic Society, Washington DC., 1986, s. 43.
19. Walter L. Starkey, The Cambrian Explosion, p. 41.
20. Walter L. Starkey, The Cambrian Explosion, p. 41.
21. Richard Milton, Shattering the Myths of Darwinism, Park Street Press, Rochester, USA, 1997, p. 170.
22. David S. Goodsell, Our Molecular Nature, Springer-Verlag, New York, 1996, p. 39.
23. David S. Goodsell, Our Molecular Nature, Springer-Verlag, New York, 1996, p. 15.
24. Gerald L. Schroeder, TThe Hidden Face of God, 3, s. 188.
25. The Incredible Machine, National Geographic Society, Washington DC., 1986, p. 190.
26. James D. Watson, The Double Helix , Touchstone, 2001, p.52-54.
27. Michael J. Denton, Nature's Destiny, Free Press, New York, 1998, p. 152.
28. Daniel C. Dennett, Darwin's Dangerous Idea, Touchstone, New York, 1996, pp. 112-113.
29. Werner Gitt, In the Beginning was Information, p. 90.
31. The Incredible Machine, National Geographic Society, Washington DC., 1986, p. 43.
32. Werner Gitt, In the Beginning was Information, p. 96.
33.http: // library.thinkquest.org /20465/DNAstruct.html
34. Michael J. Denton, Nature's Destiny, pp. 151,152 (emphasis added)
35. Ibid., p. 153.
36. Ibid., p. 406.