Leg hair phenotype in Australopithecines is under the contr

) Leg hair phenotype in Australopithecines is under the control of two independent genes. The Y gene controls hair color and has two alleles that are partially dominant. Phenotypic expression is as follows – YY is black leg hair, Yy is brown leg hair, and yy is blonde leg hair. The H gene also has two alleles that show simple Mendelian expression. The recessive allele at this gene (h) causes the legs to grow no hair at all. a. What are the expected phenotypic ratios that would result from a dihybrid cross? b. Which gene is epistatic and which is hypostatic?

Solution

Answer:

HhYy x HhYy

Black : Brown : Blonde : no hair = 3 : 6 : 3 : 4

Gene H is epistatic and the gene Y is hypostatic.