Question

What is the typical F2 ratio in the case of dominant epistasis?

Answer 1

Answer:

12:3:1

Explanation:

The typical F2 ratio in cases of dominant epistasis is 12:3:1.

The epistasis is a form of gene interaction in which an allele in one locus interacts with and modifies the effects of alleles in another locus. There are different types of epistasis depending on the type of alleles that are interacting. These include:

• Dominant/simple epistasis: Here, a dominant allele on one locus suppresses the expression of both alleles on another locus irrespective of whether they are dominant or recessive. Instead of the Mendelian dihybrid F2 ratio of 9:3:3:1, what is obtained is 12:3:1. Examples of this type of gene interaction are found in seed coat color in barley, skin color in mice, etc.
• Other types of epistasis include recessive epistasis (9:3:4), dominant inhibitory epistasis (13:3), duplicate recessive epistasis (9:7), duplicate dominant epistasis (15:1), and polymeric gene interaction (9:6:1).