1. Improvements of Domestic Animals: Almost all of our domestic animals like cows, buffalo, sheep, goats, dogs, horses, etc have been greatly transformed by the interbreeding experiments conducted by animal breeders. These experiments were conducted and are still being conducted to improve their races. For all such experiments, knowledge of genetic principles is of utmost importance.
Applied research in genetics has developed several superior breeds of domestic animals yielding more usable meat, milk, or eggs. Genetic engineering has developed new varieties of livestock. A new variety of pigs immune to influenza is being bred in Munich. New varieties of cows and buffaloes have been developed in India by artificial insemination to produce more milk.
2. Improvement of Crop Plants: In the same way, with the help of genetic knowledge plant breeders have successfully produced several superior varieties of many of our food crops. The major improvements in plant varieties have been for:
i. More efficient energy utilization during protein synthesis which results in vigorous growth and increased productivity.
ii. Increased resistance to pests, parasites, and predators.
iii. Production of hybrid varieties of different strains or different species to harness superior traits.
iv. Selection of genetic variants with increased protein value or increased content of limiting essential amino acids or increased vitamin content.
v. Production of environmental stress-tolerant varieties such as tolerant varieties of Nicotiana tabacum and temperature tolerant cell lines of N.sylvestris.
3. Genetics and Medicines: Applications of genetics in the field of medicine are numerous and very significant. Many diseases and abnormalities are known to have a genetic basis. Such serious diseases like hemophilia, cataracts, cancer, etc are all influenced by heredity. Even for tuberculosis which is a germ-caused disease, the heredity determines whether or not one will contact this disease. It is possible to avoid many serious mistakes and elaborate and expensive laboratory tests in the diagnosis of several diseases through the application of our knowledge of genetics and the family history of the person concerned.
Genetics has now evolved the technique of genetic surgery and genetic engineering which can be used for correcting the defective genotype or for biological synthesis of enzymes and hormones at the commercial level to be used for the treatment of various metabolic and horizontal disorders in man. The synthesis of monoclonal antibodies has helped in the diagnosis and treatment of a variety of diseases. Vaccines and interferons can be prepared against several epidemic diseases.
4. Legal Application: There are legal applications of the principles of heredity. Analysis of blood type, a genetically determined character is used to solve court cases of disputed parentage. Questions of baby mixups in hospitals, illegitimate children, and estate claims are often clarified by genetics.
The techniques of DNA fingerprinting, genetic imprinting, and molecular mapping have helped in forensic science involving the identification of criminals and solving doubtful parentage.
5. Eugenics: The genetic principles are used for the improvement of the human race. Although it is impossible to apply the same breeding techniques to human beings which are used for plants and other domestic animals, it is possible to apply some of our knowledge of heredity to man.