In poultry, feathered legs, F, are dominant over clean legs, f. Pea comb, P, is
ID: 22609 • Letter: I
Question
In poultry, feathered legs, F, are dominant over clean legs, f. Pea comb, P, is dominant over single comb, p.Two cocks A and B are bred to two hens C and D. All four birds are fethered-legged and peacombed.
Cock A with both hens produces offspring that are all fethered and pea. Cock B with hen C produce both fethered and clean, but all pea-combed, but with hen D, Cock B produces all feathered but three-fourths are pea-comb and one fourth are single.
What are the genotypes of these birds?
Cock A ___________
Cock B ____________
Hen C ____________
Hen D _____________
Hint:- Set up the four matings. First write the phenotypes of all individuals.
Second, write the genotypes under the phenotypes.
A x C A x D
B x C BxD
Explanation / Answer
Since B with C produces clean legged offspring, they both must be heterozygous at the F locus. Since B with D produces single comb they must be heterozygous at P locus. Thus we have A = F_ P_ B = Ff Pp C = Ff P_ D = F_ Pp Since A with either of thet wo hends did not produce any homozygous recessive offspring, it can be proposed that A has homozygous dominant genotype at both loci. The same logic applies to the other ambiguous genotypes. The final genotypes determined (with a certain amount of statistical assumption) would be A = FFPP B = FfPp C = FfPP D = FFPp