In guinea pigs, fur color is often determined by a simple Mendelian trait where black fur (B) is dominant over white fur (b).
When you cross a homozygous black guinea pig (BB) with a homozygous white guinea pig (bb), the possible combinations of alleles in the offspring can be determined using a Punnett square:
- The black guinea pig (BB) can only contribute a B allele.
- The white guinea pig (bb) can only contribute a b allele.
Thus, the offspring genotype will be:
- All offspring will receive one B allele from the black parent and one b allele from the white parent, resulting in the genotype Bb.
Since black (B) is dominant over white (b), all offspring with the genotype Bb will exhibit black fur.
Therefore, the probability that an offspring will have black fur is 100% or 1.