DNA

The other day, I was watching a program on Discovery Channel, in which some scientists were visiting Siberia in search of DNA of mammoths, which existed on the earth millions of years ago. They found some dung, tusks and other remains of these huge animals that, it is believed, were there millions of years ago.

On returning in the laboratory they tried to extricate DNA of those animals so that they could bring those species to life again. But the DNA was not complete. Some information and pairing etc was missing. This aroused my curiosity to know more about the DNA. How they knew that the DNA was incomplete? How DNA model look like? What is the material that makes a DNA? And how the DNA information could be preserved for millions of years? These are some of the questions that boggled my mind.  I am not a science student and my chemistry was average in my High School. I decided to search the cyberspace and found some information, which was sufficient to quench my thirst. Thought, I should share it if somebody can supplement it. What I learned is as follows;

DNA i.e. deoxyribonucleic acid is the building blocks of a cell. It is also responsible for carrying and retaining the hereditary information in a cell. In Microbial Metabolism, there is a class of macromolecules called nucleic acids. Nucleic acids are made of nucleotides.  And Nucleotides that compose DNA are called deoxyribonucleotides. The deoxyribonucleotide is named according to the nitrogenous bases. The nitrogenous bases adenine (A) and guanine (G) are the purines. The cytosine (C) and thymine (T) are pyrimidines. Purines and Pyrimidines are pure chemistry terms used to define the nitrogenous bases. So there are four   nitrogenous bases called “A”, “G”,”C” & “T”. In 1953- six years before I was born, James Watson and Francis Crick demonstrated that DNA was made up of two strands that are twisted around each other to form a helix. Purines and Pyrimidines make base pair which are made between “A” & “T” and “C” & “G”.  Both are complimentary base pairs meaning thereby that pairing is done between “A” & “T” and “T” & “A” and similarly between “C” & “G” and “G” & “C”. The DNA double helix contains two sequences of nucleotide code letters than run along the molecule. If you open the strands of DNA, there will be two linear sequences of the letters A C G and T. A will always pair with T and C with G.  So if you know the sequence of one strand you can work out the sequence of the other. 

DNA contains the code needed to build and control the cell. A cell makes a duplicate copy of its DNA and in that process DNA replicates. The cell than divides and each resulting cell has a copy of the DNA of its parent cell. So if the scientists have a complete DNA, they through a very complex process, can create the like species. They can also alter the look and other characteristics of the new specie. This is called genetic engineering.

Having come so far, the scientists have started believing that the essence of life can be explained with chemistry and there are no mysterious life forces.

The question is, “Is it so?” Are we nothing but chemistry? This can be true for physical body but what about the subtle body within us? Is it also nothing but chemistry? Who made this chemistry possible? An individual cell cannot function as we do. Who   made these cells join together and form flesh and bone, retina and hair? Who after all?