Question

When a cross is conducted between black feathered hen and a white feathered cock, blue feathered fowls are formed.When fowls are allowed for interbreeding , in $F-2$ -generation , there are 20 blue fowls .What would be the number of black and white fowls ?

• A. Black 20 , white 10
• B. Black 20 , white 20
• C. Black 10 , white 10
• D. Black 10 , white 20

Answer 1

Answer: (C)

Black 10 , white 10

The given problem is an example of incomplete dominance. In incomplete dominance, neither of the trait is completely expressed with one allele and the phenotype of the heterozygous trait is combination of both the alleles. When a cross is made between black feathered (BB) hen and white feathered (bb) cock, blue feathered (Bb) fowls are formed. If these fowls are allowed to interbreed, the F${}_2$ generation will have fowls in the ratio of 1 (black feathered) : 2 (blue feathered) : 1 (white feathered). If there are 20 blue fowls, then the number of black and white fowls will be 10 and 10 respectively.

Thus, the correct answer is option C.