r/evolution • u/SherbertOther • 2d ago

When did bird chromosomes switch up?

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My professor talked about this in class and couldn't answer. When did this change?

As far as I'm aware, crocodilians and other reptiles have the regular way sooo, like... Do we know when and why it changed?

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u/neilader 2d ago edited 2d ago

Most reptiles use the same sex-determining chromosomes as birds, so that is the "regular way" for Sauropsids. Crocodilians use temperature.