Jyoti Vakhlu
25th of April is celebrated as DNA day as it commemorates the discovery of double helix in 1953 and complete sequencing of Human genome in 2003. Stephan Hawking , the great theoritical physicist was of the opinion that this magnificiant earth of ours is but a small planet of a very average star. So what makes it special to us, is us. It is humbling to know that we the people, even the planet we inhabit, are but an accretion of atoms and molecules, of stardust from the beginning. Therefore that brief moment in history when stardust got converted to DNA , the life molecule, is the moment when nothing got converted into something and became poetry in chemistry .
Once man evolved from being Homo eractus to Homo sapiens and looked outwardly at night sky and inwardly at his family, there were two major mysteries to be unravelled. The greater pupose of life in this universe and connectivity and similarity of the life in family and on the large in the ecosystem. The exploration of the sky that begin with Copernican revolution is still continuing with and so is exploration regarregarding continuity and similarity of life. Mandel, the father of genetics categorically demonstrated transfer of physical entity, he called factors, move from parents to offspring . Though at that time he could not demonstrate the chemical/ organic nature of the factor , but contributions by various researchers finally led to the discovery of the molecule called DNA , that was responsible for the continuity and similarity of life on this earth.
Interestingly the molecule, DNA is very simple , made of just for building block ( the way colours of made of just 3 primary colours) and is double straded , like yin-yan and most importantly like life itself , capable of self replication. It is power of directing self replication that separates DNA from the routine stardust. Similarly presence of DNA on earth distinguishes it from rest of the planets in the solar system. Since the structure of DNA was discovered about 71 years ago the , the study of life has not remained the same, this can be compared to the moment when Newton saw apple fall.
DNA is a common thread between all life forms from viruses to elephants to man, shows exactly same mechanism for replication, recombination and transfer of information by transcription. So very interestingly we living being are nothing but the carriers /lockers for the DNA. DNA does not need cell to replicate it but more importantly for its storage and stability. Cell of which living being are made is a disaster proof locker for DNA. Philosophers speculate that DNA has created man to explore possibility of its transport to other planets. Recently there are indications where in researchers plan to sent the bacteria ( smallest and simplest locker for DNA) to other planets and see if it survives and multiples in any environment other than earth. The experiment instead of finding life on other planets is sending life to other planets . Mind it, that it is DNA via permutation and combinations of its basic units that directs biosynthesis of variety of proteins that help us survive, in present environment. To cite a basic example, the battery of enzymes that help us respirate on earth. Similarly the DNA stored in the bacteria after millions of permutation and combinations can make that perfect enzymes that may allows cell to survive in atmosphere quite different from the earth
However for the time-being, like gravitational theory mankind has used discovery of structure and function of DNA for its own use and upliftment on planet earth. Bacteria/fungi are directed to produced human proteins and hormones, by the technique called recombinant DNA technology or genetic engineering, insulin is the most apt example. Now we have moved to developing transgenic animals and plants that have surprising combination of the traits like golden rice , the rice with Vit. A precursor or Bt. cotton, the plant with a bacterial gene. The latest is genome editing wherein genes are corrected in the genome to introduce new traits or correcting the defected ones. The DNA like cosmos is intriguing but for the time being we have tamed it to be used in our service or so it seems. On this DNA day let us turn inwards and try to understandlife from within.
(The author is Professor and Director School of Biotechnology , University of Jammu, Jammu)
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