Question 1 • A rough-coated guinea pig was crossed with a smooth-coated guinea pig. All the F1 offspring were rough-coated. When the F1 were allowed to interbreed, 135 of the F2 offspring were rough-coated and 44 had smooth coat. What were the genotypes of the parental and F1 generations? Question 2 • Two black female mice (M and N) were crossed with the same brown male. In a number of litters female M produced 9 black and 7 brown offspring. Female N produced 14 black offspring. What is the mechanism of inheritance of black and brown coat colour in mice? What are the genotypes of the parents (i.e. M, N and the male). Question 3 • In chickens the white plumage colour is dominant to coloured plumage, feathered shanks are dominant over clean shanks and pea comb is dominant over single comb. Each of the gene pairs segregate independently. If a homozygous white , feathered, pea-combed hen is crossed with a homozygous coloured, clean, single-combed cock and the F1 offspring are allowed to interbreed, what proportion of the birds in the F2 will be coloured, feathered and pea-combed? Question 4 • In guinea pigs, short hair (L) is dominant to long hair (l), and the heterozygous conditions of yellow (CY) and white coat (CW) gives cream coat. A short-haired, cream guinea pig is bred to a long-haired, white guinea pig, and a longhaired, cream guinea pig offspring is produced. When the offspring grows up, it is bred back to the short-haired, cream parent. What phenotypic classes and in what proportions are expected among the F2 offspring? Question 5 • In poultry the dominant alleles for rose comb (R) and pea comb (P), if present together, produce walnut comb. The recessive alleles of each gene, when present together in a homozygous state, give single comb. A rosecombed hen was crossed with a walnut combed cock and produced offspring of which 3/8 were walnut, 3/8 rose, 1/8 pea and 1/8 single. Determine the genotypes of the two parents. Question 6 • In dogs the dominant allele S causes solid coat colour while the recessive allele s results in white spots on a coloured background. The black coat colour allele B is dominant to the brown allele b, but these genes are expressed only in the presence of the genotype a/a. Individuals that are A/- are yellow regardless of B alleles. When a solid yellow male was mated to a solid brown female six pups were produced. They are phenotypes were: 2 solid black, 1 spotted yellow, 1 spotted black and 2 solid brown. What were the genotypes of the male and female parents? Question 7 • In sheep, white hair (W) is dominant over black hair (w). Horned (H) is dominant over hornless (h) in males but recessive in females. If a homozygous horned white ram is bred to a homozygous hornless black ewe, what will be the appearance of the F1 and the F2 offspring? Question 8 • In Drosophila, white eyes are a sex-linked characters. The mutant allele for white eyes (w) is recessive to the wild-type allele for brick-red eye colour (w+). A white-eyed female is crossed with a red-eyed male. An F1 female from this cross is mated with her father, and an F1 male is mated with his mother. What will be the eye colour of the offspring of these last two crosses?