In birds, what does the male typically have in terms of sex chromosomes?

In birds, the typical male has a ZZ configuration of sex chromosomes. This means that males possess two identical Z chromosomes, which are similar in function and size. In contrast, females in birds typically have a ZW configuration, where they possess one Z chromosome and one W chromosome, with the W chromosome being significantly different from the Z chromosome.

The ZZ sex-determination system is known as a "Z-W system" rather than the XY system found in many mammals, including humans. In this system, the sex of the offspring is determined by the combination of sex chromosomes inherited from the parents. Since males carry two copies of the Z chromosome, they produce gametes that all carry a Z. Females, having a combination of Z and W, can produce gametes with either chromosome, and the combination of the male's Z and the female's Z or W determines the sex of the offspring.

Understanding this difference in sex chromosome configurations is crucial for comprehending sex determination mechanisms in birds, as it highlights how avian species have evolved distinct sexual differentiation systems compared to mammals.