In the last few decades, the science of genetics has pervaded all aspects of biology so that it has assumed a central position of great significance in biology as a whole. While on the one hand, genetics is used for a study of the mechanism of heredity and variation, on the other hand it has provided tools for the study of the fundamental biological processes examined and taught in areas, like plant physiology, biochemistry, biosysterjiatics, ecology, plant pathology, microbiology, etc. Consequently today every biologist should be bit of a geneticist. Genetics, in fact provided the modern paradigm (a prototype) for whole of biology. The science of genetics also had a tremendous impact in applied areas including medicine, agriculture, forestry, fisheries, law and religion. In view of this, all newspapers often address questions dealing with different aspect of genetics that may be of significance to common man, who is not a genetici' or a biologist. The recent upsurge of biotechnology has added further to the significance of the science of genetics, so that the products of genetics have also become a subject of discussion for Trade Related Aspects of Intellectual Properties (TRIPs) under the aegis of General Agreement on Tariffs and Trade (GATT). Patenting of life forms which may or may not be the product of genetic manipulation is one such topic, which is receiving considerable attention of both developed and developing countries.
Genetics can be broadly classified in the following three areas for the convenience of a discussion on its scope and significance : (i) transmission genetics involving study of transmission of genetic material from one generation to the other; (ii) molecular and biochemical genetics, involving study of the structure and function of genes and (iii) population and biometrical genetics, involving study of the behavior and effects of genes in population, often using mathematical models. The above classification is arbitrary, and the three areas are inter-related and even enter other areas of biology to answer some difficult questions. Significance of genetics also stems from the fact that the genetic material containing information for hereditary traits consists of nucleic acids only, across the entire spectrum of life on the earth. More important of tlie two types of nucleic acids, deoxyribose nucleic acid (DNA) and ribose nucleic acid (RNA), is the former i.e. DNA, which has two unique properties : (i) it can replicate and produce its exact copies and (ii) it carries the genetic information, necessary to give form to an organism; this information is written into the sequence of four monomers called nucleotides, which make the polymer molecule, the DNA.