White Leghorn chickens are homozygous for a dominant allele, C, of a gene responsible for coloured feathers, and also for a dominant allele I, of an independently segregating gene that prevents the expression of C. The White Wyandotte breed of chickens is homozygous recessive for both genes, c/c,i/i. What proportion of the F2 progeny obtained from mating White Leghorn X White Wyandotte would be expected to have coloured feathers? SCHOOL OF APPLIED SCIENCES Question 2. (5 Marks) Seborrheic keratosis is a rare hereditary skin condition due to an autosomal dominant mutation. Affected people have skin marked with numerous small sharply margined, yellowish or brownish areas covered with a thin greasy scale. A man with keratosis marries a normal woman and they have three children. a. What is the chance that all three are normal? b. What is the chance that all three are affected? Question 3. (10 Marks) Plumage in ducks is determined to some extent by a series of multiple alleles named restricted (MR = white on the wing fronts), mallard (M = wild type), and dusky (md = darker plumage). MR is dominant to M, which is dominant to md (i) Can the mating between two mallard ducks produce any offspring with restricted plummage? Explain. (ii) A series of matings between two mallard ducks produced the following offspring: 34 mallard and 11 dusky ducks. What are the likely genotypes of the two mallard parents? (iii) Can a mating between two ducks with restricted plumage produce offspring with dusky plumage? Explain using diagrams of appropriate matings.