In the early decades of the twentieth century T.H. Morgan and his associates A.H. Sturtevant, H.J. Muller, C.B. Bridges and a few others at Columbia University, New York were actively engaged in studies on Chromosome Theory of Heredity with a very suitable material Drosophila. From their studies on mutants in Drosophila they could assign several genes to chromosomes. For their [...]
In this article we will discuss about the presence of DNA in mitochondria and chloroplasts. The presence of organelle-specific DNA in mitochondria and chloroplasts was identified with certainty over three decades ago. The occurrence of a specific chloroplast DNA was first demonstrated by Chun et al. in 1963, and of mitochondrial DNA a year later by Luck and Reich (1964). [...]
The failure of pollen formation results in male sterile plants. In some crop plants male sterile mutants occur in which inheritance of male sterility follows one of the following two patterns: those in which the trait is inherited through a single recessive chromosomal gene segregating in Mendelian ratios; secondly, those that show maternal transmission. Rhoades in 1933 described maternal inheritance [...]