In this article we will discuss about:- 1. Definition of Epistasis 2. Types of Epistasis 3. Epistasis in Drosophila 4. Epistasis and Blood Groups in Man. Definition of Epistasis: Due to the phenomenon of dominance a recessive allele remains obscure in the hybrid. But when two different genes which are not alleles, both affect the same character in such a [...]
In this article we will discuss about the co-dominance and incomplete dominance. The phenotypic ratios obtained by Mendel in garden peas demonstrate that one gene controls one character; of the two alleles of a gene, one allele is completely dominant over the other. Due to this the heterozygote has a phenotype identical to the homozygous parent. Soon after Mendel's work [...]
Griffith was working with the micro-organism Diplococcus pneumonia also called Pneumococcus, a bacterium causing pneumonia. Some strains of this bacterium have a smooth polysaccharide capsule which causes disease and are designated as virulent S type strains. In a mutant strain the bacteria have no capsule, and when grown on the surface of an agar plate, they form small rough colonies [...]