The speckled chicken on the right results from a cross between a black and white chicken. Explain what type of inheritance this would be, and draw a punnett square to show how this would happen.

This gene inheritance is called codominance, where both alleles can be expressed. In these cases, heterozygote individuals instead of showing an intermediate phenotype, express both alleles. Their phenotype is an additive expression of their parents' genes.

When two individuals, homozygous for a certain trait, are crossed they produce heterozygous individuals that express both alleles equally.

A typical example of codominance is the case of speckled chicken, the product of the cross of a black individual with a white individual. Black chickens (BB) only have this gene for feather color, while white chickens (WW) only have the gene for white feathers. When they cross, their progeny will have both genes (BW), and both of them will be expressed as speckled feathers.

Cross:

Parental) BB x WW

Black White

Gametes) B B W W

Punnet square) B B

W BW BW

F1) 100% BW, speckled individuals.