The Ultimate Guide to Guinea Pig Breeds, Markings and Colors – Kavee USA
In guinea pigs, rough coats (with lots of swirly cowlicks) are dominant over smooth coats. If a male homozygous recessive guinea pig is crossed with a female homozygous dominant guinea pig, what are the possible genotypes and phenotypes of the offspring? Complete the Punnett square and the percentages of rough and smooth coated offspring.
To determine the possible genotypes and phenotypes of the offspring, we can use a Punnett square.
Homozygous dominant female: RR (smooth coat)
Homozygous recessive male: rr (rough coat)
Therefore, the genotypes of the offspring will all be Rr (heterozygous, smooth coat).
Punnett square:
R R
r Rr Rr
r Rr Rr
The percentages of rough and smooth coated offspring will be 100% smooth coated. This is because the rough coat trait is recessive, so the offspring must inherit two recessive alleles (rr) to have a rough coat. As the male guinea pig is homozygous recessive (rr) and the female is homozygous dominant (RR), all the offspring will inherit one dominant allele (R) from the female and one recessive allele (r) from the male, resulting in a smooth coat phenotype for all the offspring.