The work of Mendel and others who followed him gave us an idea of inheritance patterns. However the nature of those ‘factors’ which determine the phenotype was not very clear. As these ‘factors’ represent the genetic basis of inheritance, understanding the structure of genetic material and the structural basis of genotype and phenotype conversion became the focus of attention in biology for the next century. The entire body of molecular biology was a consequent development with major contributions from Watson, Crick, Nirenberg, Khorana, Kornbergs (father and son), Benzer, Monod, Brenner, etc.
A parallel problem being tackled was the mechanism of evolution. Awareness in the areas of molecular genetics, structural biology and bio informatics have enriched our understanding of the molecular basis of evolution. In this unit the structure and function of DNA and the story and theory of evolution have been examined and explained. Chapter Principles of Inheritance and Variation Chapter Molecular Basis of Inheritance Chapter Evolution James Dewey Watson was born in Chicago on April .
In , he received B.Sc. degree in Zoology. During these years his interest in bird-watching had matured into a serious desire to learn genetics. This became possible when he received a Fellowship for graduate study in Zoology at Indiana University, Bloomington, where he received his Ph.D.
degree in on a study of the effect of hard X-rays on bacteriophage multiplication. He met Crick and discovered their common interest in solving the DNA structure. Their first serious effort, was unsatisfactory. Their second effort based upon more experimental evidence and better appreciation of the nucleic acid literature, resulted, early in March , in the proposal of the complementary double-helical configuration.
Francis Harry Compton Crick was born on June , at Northampton, England. He studied physics at University College, London and obtained a B.Sc. in . He completed Ph.D.
in on a thesis entitled “X-ray Diffraction: Polypeptides and Proteins”. A critical influence in Crick’s career was his friendship with J. D. Watson, then a young man of , leading in to the proposal of the double-helical structure for DNA and the replication scheme.
Crick was made an F.R.S. in . The honours to Watson with Crick include: the John Collins Warren Prize of the Massachusetts General Hospital, in ; the Lasker Award, in ; the Research Corporation Prize, in and above all, the Nobel Prize in . J AMES W ATSON F RANCIS C RICK