Question

A black rooster mates with a white hen. Based on their genotypes, the chance that the offspring will be checkered is 100 percent.
What is the rooster’s genotype? A) BB B) Bb C) bb D) BW
What is the hen’s genotype? A) WW B) Ww C) ww D) BW

Answer 1

Well, since the phenotype is checkered, we assume that there is codominance where offspring phenotype is a mix of the parents' phenotypes.  If the offspring phenotype is a blend between the two parents', then there is incomplete dominance.

Genotypes of codominant parents is usually represented by upper case letters B and W, and the mixed genotype would be BW.

Since the genotype BW is 100%, the rooster's genotype can only be BB and the hen's genotype can only be WW to result in 100% BW.

The correspond Punnett square is therefore
       B     B
W  BW  BW
W  BW  BW

By the way, apparently that this example is academically made up, there are no checkered chickens.  I don't know if this is true, since I don't raise enough chickens to verify this.  :)