Platapus sex

Louis, Missouri , USA. In mammals, with a few notable exceptions, sex is determined by an XX female:XY male sex chromosome system in which the Y chromosome bears the male-dominant testis-determining gene SRY. The X chromosome of most placental mammals has a virtually identical gene content, whereas the degenerate Y chromosome contains overlapping subsets of only a few active genes for review, see Graves Marsupial mammals have a smaller X and Y that represent an ancestral therian mammal sex pair and define the ancient region of the human sex chromosomes. The mammal X and Y evolved from a pair of autosomes after the proto-Y acquired a male-determining gene, X—Y recombination between male-advantage genes was suppressed, and the Y degenerated Charlesworth et al.

Metrics details. Sex-determining systems have evolved independently in vertebrates. Placental mammals and marsupials have an XY system, birds have a ZW system. Reptiles and amphibians have different systems, including temperature-dependent sex determination, and XY and ZW systems that differ in origin from birds and placental mammals.

With the bill and webbed toes of a duck, tail of a beaver and body of an otter, platypuses are easily one of the strangest-looking animals on the planet. But are the mating behaviors of these mammals just as odd as their appearance? As the only living member of the taxonomic family Ornithorhynchidae and genus Ornithorhynchus , the platypus Ornithorhynchus anatinus is a unique animal that lives throughout Tasmania and the eastern coast of Australia. Duck-billed platypuses are generally solitary animals, especially the males, which set up territories in rivers, lagoons and streams. The different home ranges of males may overlap, but the animals try to avoid each other, possibly even changing their foraging schedule to do so.

Platypus sex The gene that most likely determines the sex of the platypus and echidna has been identified by Australian and Swiss researchers. The study also shows that the Y chromosome, contrary to previous assumptions, carries genes that are important to the basic viability of male mammals, says geneticist Dr Paul Waters from the University of New South Wales. Although the Y chromosome is known to be important in sex determination, little is known about the function and evolution of its genes, says Waters.