Question

In pigs, the allele for a wavy, rough coat (R) is dominant to the allele for a soft, fine coat (r). A rough coat boar and a soft coat sow mate. They produce several litters, 50% are rough coat and 50% are smooth coat. What were the genotypes of the parents?

Answer 1

Answer:

The genotypes of the parents are Rr and rr. The possible genotypes (and their phenotypes) are: RR (rough coat), Rr (rough coat), and rr (smooth coat). In a cross of rough coat boar (RR or Rr) and a soft coat sow (rr), there are half of the offspring with the smooth coat. We know that sow must be rr, but the boar can be RR and Rr. If it was RR, all of the offspring would be Rr and would have the rough coat. So, the boar has genotype RR.

Answer 2

The genotype of the rough coated parent would be Rr (heterozygous) and the genotype of the soft coated parent would be rr (homozygous recessive).