Bird Genetics

Birds have a different sex chromosome configuration than mammals. The sex chromosomes of birds are called Z and W while those of mammals are called X and Y. The Z chromosome is the carrier of the most sex linked genes of interest for the chicken breeder.

Male birds have 2 Z chromosomes per cell. Female birds only have one Z chromosome and one odd partner chromosome called W, per cell. The W chromosome does not carry many genes of interest for the chicken breeder.

The sex chromosome configuration causes the phenomenon of sexlinked inheritance .

Birds can be sexual dimorphic: Male and female expressing different traits. These do not have to be sexlinked.