January 28, 2010

Jenny Graves The Australian National University, Research School of Biological Sciences

Comparisons between distantly related mammals and other vertebrates – including kangaroos and platypuses, devils (Tasmanian) and dragons (lizards) – can help explain how human sex chromosomes evolved and explain why they are so weird. The human X chromosome is full of “brains-and-balls” genes that were important in the rapid evolution of humans, while the human Y is a pathetic little chromosome that lost most of its genes, other than a sex determining gene. It is degrading rapidly and may be entirely lost in the next few million years, with unexpected consequences to the human race.