In guinea pigs, hair length and colour are controlled by two geneson different chromosomes. The hair may be either long or short andits colour either black or brown.
A male guinea pig and a female guinea pig both had short, blackhair.
The male was homozygous for hair length and the female washomozygous for hair colour. Repeated crossings of these two guineapigs resulted in offspring of four different genotypes, all ofwhich had short, black hair.
Complete the genetic diagram to explain these results. Write in thebox the symbols you will use to represent the alleles.
Allele for short hair: _____ Allele for long hair: ______
Allele for black hair: ______ Allele for brown hair: ______
Male Female
Parental phenotypes: Short, black hair. Short, black hair.
Parental genotypes: ______________ ______________
Gamete genotypes: ______________ ______________
Offspring genotypes: _______________ _______________
Offspring phenotypes: ________________ ________________
Is this right?
Allele for short hair: S Allele for long hair: s
Allele for black hair: B Allele for brown hair: b
Male Female
Parental phenotypes: Short, black hair. Short, black hair.
Parental genotypes: male SSBb female SsBB
Gamete genotypes: male SB, Sb female SB, sB
Offspring genotypes: SSBB, SSBb, SsBB, SsBb
Offspring phenotypes: Short, black hair