If we altered the epitasis model in the slide below so that

If we altered the epitasis model in the slide below, so that dogs that are heterozygous at both loci have white pigment, what proportion of the progeny of the cross have white pigment? Two or more genes can interact to produce certain phenotypes in a population.

Solution

Answer:

Recessive alleles at one locus (ee) mask the phenotypic expression of other gene locus (BB,Bb or bb) such epistasis is called recessive epistasis. The alleles of ‘B’ locus express themselves only when epistatic locus ‘E’ has dominant allele like EE or Ee. The phenotypic ratio is 9: 3: 4.

Black = B_E_

Choclate = bbE_ or bbee

White = B_ee or bbee

9 (Black) : 3 (CHocklate) : 4 (White)