Sex chromosome
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Sex chromosomes are chromosomes that carry the genes that determine the sex of an individual. The human sex chromosomes are a typical pair of mammal allosomes. They differ from autosomes in form, size
Mice X Y chromosomes
XY sex-determination system
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The XY sex-determination system is a sex-determination system present in many mammals, some insects, some snakes, some fish, and some plants.
Sex chromosome
…and UV systems as well as many variants. Sex chromosomes have evolved independently across many plant groups. Recombination of chromosomes may lead to heterogamety before the development of sex chromosomes, or recombination may be reduced after sex chromosomes develop. Only a few pseudoautosomal regions normally…
Pollen cones of a male Ginkgo biloba tree, a dioecious species
Ovules of a female Ginkgo biloba
PBB Protein SRY image
Nettie Stevens in 1904