Feather colour in Andalusian chickens is controlled by a gene with two alleles.
The FBF^BFB allele codes for black feathers and the FWF^WFW allele codes for white feathers.
When a black-feathered chicken is crossed with a white-feathered chicken, the offspring (chicks) have blue feathers.
This colour is seen because of codominance, resulting in a mixture of black and white appearance that looks blue.
Use the symbols FBF^BFB and FWF^WFW to show how the black-feathered parent and the white-feathered parent can produce a blue-feathered chick.
Parents:
Gametes:
Offspring genotype:
The blue-feathered chick is later mated with another blue-feathered chicken. Give the possible genotypes and phenotypes of their offspring.
A blue-feathered chicken is mated with a white-feathered chicken. What is the probability of producing a white-feathered offspring?
Seed shape in pea plants is also controlled by a gene that has two alleles. The seed shape can either be round or wrinkled. Explain how the genetic control of seed shape in pea plants differs from the genetic control of feather colour in Andalusian chickens.
Chickens usually produce a relatively small number of offspring from each mating. Scientists often study genetics using model organisms such as fruit flies (Drosophila). Suggest one advantage of using fruit flies rather than chickens to study genetics.
