The common point of attachment of all the arms of polytene chromosome, is known as

Genes that are similar in phenotypic effect when present separately, but together interact to produce a different trait and ratio is $9 : 7$ in $F_2$ generation. What are such genes known as

One of the parents of a cross has a mutation in its mitochondria. In that cross, that parent is taken as a male. During segregation of ${F_2}$ progenies that mutation is found in

Expected children of a blue-eyed $(recessive)$ woman and brown-eyed $(dominant)$ man who had a blue-eyed mother are likely to be

Individuals having homomorphic sex chromosomes produce