You cross a true breeding pea comb chicken with a single comb

you-cross-a-true-breeding-pea-comb-chicken-with-a-single-comb

You cross a true breeding pea comb chicken with a single comb chicken. What will you observe in the F2 generation?

A. Ratio 1:2:1

B. Ratio 3:1

C. Ratio 9:3:3:1

D. All pea combed

I got this question in semester exam.

My question comes from Gene Interactions topic in section Extension and Deviation from Mendelian Genetic Principles of Cytogenetics

The correct choice is D. All pea combed

The best explanation: Pea comb has genotype P/P r/r and single has genotype p/p r/r. Thus the cross will give F1 P/p r/r. This is homozygous recessive at R locus so F2 will only differ in P locus giving monohybrid ratio 3:1.