Question

Epistasis and extensions of basic heredity 1. What is the difference between two genes affecting a single character and epistasis? What is special about epistasis? 2. How can we use the genotypic abbreviations of phenotype (shorthand gentotypes) (e.g., 9A_B_, 3A_bb, 3aa3_, laabb) to understand what is happening in epistasis? 3. For the example of the Y allele in mice (from the text), explain why yellow coat coloration is ominant, but lethality is recessive. You may use figures to support your argument.

Answer 1

1. Epistatis is the control of one one gene by another gene (s).

But two gene responsible for one trait is nothing but both gene are responsible for showing the phenotype both gene are responsible noone is controlling noone they become expressed independently.

Whereas epistatis happens when one gene's effect is controlled by other gene(s).

If normal allele then they phenotypic ratio will be more diverse otherwise in epistatis one phenotype frequency will be more. Example of epistatis is suppose one gene is controlling a pigment synthesis and to show colour one another allele is needed to be expressed which will make the the pigment to be expressed.

And two allele controlling one trait will be multiple gene like blood groups of human