These are the four bases of DNA – abbreviated as A,C,G and T.“The vocabulary consists of the ‘triplet code’ – three bases of DNA – which, read together, encodes one amino acid in a protein (there are 20 amino acids in all). A protein is the ‘sentence’ encoded by the gene using alphabets strung together in a chain.
“The ‘regulator’ sequences appended to a gene that turn a gene on or off at certain times and in certain cells can be imagined as the internal grammar of the genome. These sequences might be likened to punctuation marks and annotation – inverted quotes, a coma, a capitalised letter,” and the language is complete.
With such metaphors and puns generously sprinkled across its 545 pages to explain the difficult concepts of genetics, you don’t need a degree in biology to read and appreciate The Gene – An Intimate History by New Delhi-born Dr Siddhartha Mukherjee, a cancer researcher at New York’s Columbia University and Pulitzer Prize-winning author of The Emperor of All Maladies: A Biography of Cancer (2010).
While practically trying to teach a whole course in genetics, the book, as its title says, “is a very personal story.” Mental illness had claimed Mukherjee’s two uncles on his father’s side, and his cousin is confined to a mental asylum in Kolkata.
“The history of mental illness in the family and the heredity component that lurked behind it was cutting through my consciousness,” says Mukherjee. To give vent to his feelings he decided to tell the story of the gene.
And the way the story unfolds in his skilled hands will tempt a reader to finish the book in one go. As Paul Berg, winner of the Nobel Prize in Chemistry, commented on the book, which is packed with all the famous names in genetics: “It is a magnificent synthesis of the science of life.”
No doubt the science of biochemistry and cellular biology gets increasingly complex as you turn the pages but Mukherjee, adept with metaphors and writing in a journalistic style, can explain difficult genetic concepts with great clarity and simplicity.
The guided “gene tour” begins with Aristotle (350 BC), who argued that hereditary information is transmitted in the form of messages, and takes you to Darwin (1859) who theorised that humans descended from ape-like ancestors and then on to the Augustine monk, Gregor Johann Mendel.
To understand heredity, Mendel (1865) bred mice in his room to produce hybrids and then switched his experiments to pea plants in the flower garden in his monastery.
By studying the progeny produced by the crosses, he concluded that heredity could be easily explained by the passage of discreet pieces of information from parents to offspring. “He did not give this unit of heredity a name but he had discovered the essential features of a gene,” says Mukherjee.
If heredity was transmitted as information, how was that information encoded and translated?Answers to these and many more questions came from a string of post World War-II discoveries beginning with the identification owf DNA, or deoxyribonucleic acid, as the carrier of genetic information, and the finding that DNA is actually made of two intertwined helical chains.
“If genes determine the nature and fate of an organism, and if organisms now begin to determine the nature and fate of their genes, the circle of logic closes on itself,” says Mukherjee. “We need a manifesto, or at least a hitchhiker’s guide, for a post genomic world."