Question

Use LOGIC and NO Punnett squares to answer the following: In cocker spaniels, the following genotypes and phenotypes are found (a "?" indicates that either a dominant or recessive allele may be present to give the same phenotype): AABB = white A?bb = red aabb = lemon AaB? = black aaB? = liver AABb = grey A black male is mated with a liver-colored female, and they produce the following black, red, liver-colored and lemon-colored pups. What are the genotypes of the two parents? (please EXPLAIN how you arrived at your answer to receive credit.)

Answer 1

The genotypes of the two parents are female = aaBb and male = AaBb

From the alleleic combination, we can say that black is produced when it get A and a allele. So among the parents one should contribute A and other should contribute a. If you see red pup, it needs two bb, so each parents should give one b to the pup. So each parent is having one b in them. To get liver colored pup, we need two a, so each parent is having a in them. To get lemon colored pup, we need aabb, so each parent should give ab to the pup.

Now try to keep all the possible combinations, finally we will come to a conclusion that the female parent is aaBb and male parent is AaBb.