Question

In poultry, two genes, R and P, control the shape of the comb on the head. The following genotype/phenotype relationship applies to these two genes: R- P- animals have a 'walnut' comb; R- pp animals have a 'rose' comb; rr P- animals have a 'pea' comb; rr pp animals have a 'single' comb. What will the comb phenotypes of the progeny be for a cross of rr PP X rr Pp animals

Answer 1

100% of the progeny will have a pea comb, rrP-

Step-by-step explanation:

Available data:

• two genes, R and P, control the shape of the comb on the head
• R- P- animals have a 'walnut' comb
• R- pp animals have a 'rose' comb
• rr P- animals have a 'pea' comb
• rr pp animals have a 'single' comb

Cross:

Parentals) rrPP x rrPp

Gametes) rP, rP, rP, rP rP, rP, rp, rp

Punnett square) rP rP rP rP

rP rrPP rrPP rrPP rrPP

rP rrPP rrPP rrPP rrPP

rp rrPp rrPp rrPp rrPp

rp rrPp rrPp rrPp rrPp

F1) Genotype

• 8/16 = 1/2 = 50% of the progeny will be rrPP

• 8/16 = 1/2 = 50% of the progeny will be rrPp

Phenotype

16/16 = 100% of the progeny will have a pea comb