Genetics is the study of heredity and variation. The genes present in the nucleus and cytoplasm governs the heredity and variation. The nuclear x cytoplasmic interaction largely determines the phenotype, apart from the environmental factors. Gregor Johann Mendel laid the foundation for the classical nuclear genetics. The science of organelle genetics began in 1908, with the discovery of variegation of leaf colour in 4 0' clock plant (Mirabilis Jalapa). This ...
