24 February 2009

DNA - junk or secret code?

I wrote this way back in 2003 which was the 50th anniversary of the discovery of DNA - it hasn't had the chance of being read yet. Deviating from my usual enviro-stuff, I'm going back to the place where everything really started for me.

It all started on that day which will go down in history. Two virtually unknown scientists James Watson and Francis Crick announced in the Eagle Pub in Cambridge, England that they had discovered 'the secret of life'. On April 25, 1953, it was announced to the world in a one-paged letter to Nature. It started with probably the most famous understatement in the history of science: “We wish to suggest a structure for the salt deoxyribose nucleic acid (DNA). This structure has novel features which are of considerable biological interest”.

The double helix has produced a lot more than ‘considerable interest’. It has shaped a whole new branch of science, a branch that has developed biology into something exciting, creative and alive. Possibilities herewith thought impossible, which remained mere speculations are now staring at our face with remarkable clarity. Along with all this of course, it has raised ethical debates and discussions and a furor which has never before been seen in biology. The discovery of DNA heralded a new era, the dawn of Genetic Science. Watson and Crick obviously did not realise the impact it would make when they published their findings in such stark modesty.

DNA is the carrier of the genetic code and thus the key molecule in hereditary, developmental biology and evolution. It is twisted into little pieces and packed into the nucleus of each cell. The blueprints for making proteins are stretches of DNA called genes. The instructions are spelled out in four-letter codes: A, T, G and C. In order to replicate, DNA which is a double helix, unzips along its length and unravels the two half-ladders that are reverse images of each other. Then each half rebuilds itself from components stored in the cells. Because As always bond with Ts and Gs always bond with Cs, the finished copies are identical. This amazing process occurs almost continuously through out lives, replacing worn out cells and producing new ones. DNA also has the ability to ‘proof-read’ this process and corrects any mistakes in pairing as it goes along.

In 1990, the Human Genome Project was officially launched. In the midst of that, Dolly, the first cloned mammal made her appearance in 1997. In 2000, Venter and Francis Collins announced together that they have sequenced the human genome. "We are learning the language in which God created life," said President Clinton in a conference soon after.

The 3.1 billion units of genetic information stored in our chromosomes are the building blocks of life itself. Although the President’s words were spot on, they had a different ring to many biologists. Majority of them believed it is natural selection – not God – that created the human genome, over billion years of evolution.

Although biologists have finished sequencing genes, they do not understand most of it. Why? Think of it this way. Suppose you found an ancient wall covered with strange marks. Some seem to be words in an unknown language, while others are simply random scratchings or gibberish. How do you distinguish the two? This is how modern evolutionary biologists view the information in our genome. In their view, the ‘gibberish’ is simply ‘junk DNA’ -- functionless, meaningless scraps and leftovers, which we have inherited from our animal ancestors. As they see it, only two forces could explain the origin of our genome: natural laws and blind chance, which equate to the process of natural selection. Therefore, if there is gibberish, you just dismiss it. After all, the author’s only goal was survival.

However, this is the easy way out. What if natural selection is incapable of creating such information? Even the most ardent Darwinian biologists agree that our genome contains tens of thousands of meaningful sequences, inspite of all the junk. What if the junk is not junk at all? What if it is a secret code we are yet to decipher? As Phillip Johnson argues in his book, ‘The Wedge of Truth’, "meaningful information-bearing sequences require some third force that works against both repetitive order on the one hand and chaotic chance on the other." And that, he says, would be a designing mind.

If God, not natural selection, designed the human DNA, maybe the so-called ‘junk DNA’ may have important functions. It is just written in a language beyond our present means of understanding. Whether we will eventually figure it out or whether it will remain a mystery forever, depends on divine will. The view that our genome is not just junk, but an intricate code we have yet to understand, holds vast promise and exciting possibilities. It is something the principles of natural selection can never offer.

Science without religion is lame, religion without science is blind
- Einstein

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