Answer:
So that in a guinea pig cross in the offspring the recessive trait —long hair— can be observed in 25%, the most probable genotype of the parents is heterozygous Ss.
Explanation:
In guinea pigs, for the characteristic hair length, short hair is the dominant allele and long hair is the recessive one.
In order for 25% of the offspring to express the recessive characteristic, the parents must have a recessive genotype, which can be seen in Punnett's Square:
P: Ss X Ss
Alleles S s
S SS Ss
s Ss ss
Where the offspring is:
- 50% Ss with short hair phenotype
- 25% SS with short hair phenotype
- 25% ss whose phenotype would be long hair.
According to this, heterozygous parents for the characteristic long hair in guinea pigs have a 25% chance of having offspring with long hair.
