Biochemical genetics
As the science of genetic developed, increased attention was given to what are genes and how do they function? More experimental use was made of microorganisms, notably bacteria and bacterial viruses. The knowledge of protein and nucleic acid in the ninety thirty greatly influenced early ideas about the chemical nature of the genetics material. Avery and associates established in in ninety forty four by that genes are composed of macro molecules called deoxyribonucleic acid(DNA) that passes from one generation to the next and dictates the inherent properties of a species. In ninety four one, G. W. Beedle and E. L. Tatum studied biochemical mutants in common bread mould, Neurospora, and proposed that each gene produces a particular enzyme which catalyzes a specific biochemical reaction. It established how genes function. This study started a new branch of genetics known as biochemical(molecular) genetics.
M. W. Nirenberg and coworkers in 1961 deciphered the genetic code often referred as triplet code since the code for one amino acid has three nucleotides. They were the first to demonstrate that three uracils(UUU) in messenger RNA code for a molecule of phenylalanine. Subsequently, the same workers determined the codes for other amino acids.
S. Ochoa was successful in the in vitro synthesis of RNA(ribonucleic acid) and A. Korenberg developed the technique for in vitro synthesis of DNA. Hargovind Khorana and associates synthesized in 1970 a sequence of DNA nucleotides(gene) using a known sequence of nucleotides in transfer RNA molecule in vitro which functioned normally in transcription.
In recent days, phenomenal developments in the field of genetics are taking place. Technique for the production of recombinant DNA has been developed by Paul Berg. This technique, called molecular genetic engineering will help man to modify genes and even to synthesize desired genes for replacement of defective genes producing hereditary diseases. DNA carrying genes coding for desirable proteins of one species can be inserted into the chromosomes of another species which is then inherited like any other gene. A cell so produced is called transgenic. The application of genetic engineering to commerce is broadly called biotechnology. It is thought that the biotechnology industry, with genetics as its basis, will become one of the most profitable industry of the coming decades.