Scientists at UC Berkeley are studying how sex chromosomes in animals can yield information about the reproductive history of a species. From fruit flies (one of the most popular case studies) to emus, each species differentiates chromosomes and assigns genetic information to those chromosomes in a particular way.
For instance, the XY pair of sex chromosomes we’re used to discussing in humans is not present in the sexual differentiation of every species. Ideally, comparing animal sex chromosomes across a wide variety of species will help us learn more about the purpose of biological sex.
As sex is not the only way for a species to reproduce, it’s interesting to think about the reasons we–and other creatures–have sex chromosomes and sex traits at all.