English

ZW sex determination in birds (as exemplified by chickens)

Proper noun

ZW system

1. (biology) The system that determines the sex of birds, some fish and crustaceans such as the giant river prawn, some insects (including butterflies and moths), and some reptiles, including Komodo dragons, in which males have two of the same kind of sex cell (ZZ, sometimes called XX) and females have two distinct sex cells (ZW, sometimes called XY).

Alternative forms

• ZZ-ZW system

See also

• XY system
• X0 system