Question

Feather color is a highly prized trait in chickens. One of the genes that controls feather color has two alleles, black (Bl) and blue (bl+). A chicken that has two black alleles (Bl/Bl) is black, and a chicken that has two blue alleles is blue (bl+/bl+). However, a chicken that inherits one of each trait (Bl/bl+) is an intermediate of the two. If two intermediate-colored chickens together produced 100 chicks, how many would you expect to be black?

Answer 1

Answer: Twenty five (25) of the chicks will be black.

Explanation: A cross between two heterozygous chicks (Bl/bl+) will produce four chicks; one will be Bl/Bl, two will be Bl/bl+ while one will be bl+/bl+.

A break down of the phenotypes is as follows:

Genotype ==> Phenotype

Bl/Bl ==> Black

Bl/bl+ ==> intermediate

bl+/bl+ ==> blue.

Since one out of four offsprings (1/4) is black, therefore if the two chicken produce 100 chicks, the number of chicks that will be black is 1/4 x 100 = 25.

See the punnett square for more information