Crosses involving gene interactions?

Question

Question:

In poultry, there are two independantly assorting gene loci, each with two alleles that affect the shape of a chicken's comb. On locus has a dominant allele (R) for rose comb while its recessive allele (r) produces a single comb. The other allele has a dominant gene (P) for a pea comb while is recessive allele (p) also produces a single comb. When the two dominant genes occur together (R-P-), a walnut comb is produced. So, R-P- = walnut, R-pp=rose, rrP- = pea, and rrpp= single. Give the expected phenotypic ratios of offspring from the following matings:

1. RRPP x rrpp

2. RrPp x rrpp

3. Rrpp x rrPp

5. RrPP x RrPp

6. rrPp x RrPP

Answer 1

1. RRPP x rrpp = all walnut combs

2. RrPp x rrpp = 4 walnut, 4 rose, 4 pea + 4 single

3. Rrpp x rrPp = 4 walnut, 4 rose, 4 pea + 4 single

5. RrPP x RrPp =11walnut, 1rose, 3pea + 1single

6. rrPp x RrPP = 8 walnut and 8 pea combs