Question

In a species of chickens, incomplete dominance between alleles for black (B) and white(w) feathers

is observed. Heterozygotes are blue.
• If two blue chickens are crossed, what is the probability that the offspring will be blue.

Answer 1

1/2

Step-by-step explanation:

This question involves a single gene coding for feather color in chickens. The black allele (B) is incompletely dominant over the white allele (W). This means that the allele B will not mask the phenotypic expression of allele W, hence, a third intermediate blue phenotype (BW) will be produced.

According to the question, if two blue chickens are crossed i.e. BW × BW, the gametes B and W will be produced by each parent. Using these gametes in a punnet square (see attached image), the following offsprings will be produced:

BB, BW and WW in the ratio 1:2:1

BB is black, BW is blue, WW is white. Hence, the probability of producing a blue chicken from this cross is 1/2.