Q39 - Sex-Linked Plumage Colour Inheritance in Chickens
Egg producers prefer hens to roosters, and they select these by using sex-specific traits. Roosters have the sex chromosomes ZZ and hens have ZW (W is a dwarf chromosome perhaps without coding information). In a parental crossing (P) between a black-coloured rooster and a barred (coloured stripes) hen all male chickens became barred and all female chickens black. Breeders knew beforehand that only one gene was involved in the trait.
Using the information and data, determine which of the statements are true or which are false.
A. Black plumage dominates over barred
B. All barred chickens in F2 can be regarded as hens and used for egg production
C. Half of the male chickens in F2 are heterozygous
D. All male chickens in F2 are black
Question reproduced from IBO 2015, Theoretical Exam A, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)