Sex chromosomes in the domestic fowl (gallus domesticus), turkey (meleagris gallopavo) and the chinese pheasant (phasianus colchicus)

A small W-sex chromosome is described in the female karyotype of the domestic fowl (Gallus domesticus), turkey (Meleagris gallopavo) and pheasant (Phasianus colchicus). In the domestic fowl, the W-chromosome is a small unpaired, metacentric chromosome intermediate in size between the chromosomes of the ninth and the tenth pair. In the female turkey, the W is a sub-metacentric element with an arm ratio of about 1:2 and a size intermediate between that of the sixth and the seventh pairs. In the case of the female pheasant, the Wis an unpaired, sub-metacentric element with an arm ratio of approximately 1:2.4 and a size slightly larger than that of the seventh pair.