Rogue genes on X chromosome turn on in testicles

The most predictable mammalian chromosome has a wild side. The X chromosome — long thought to be pretty much the same across mammals — actually harbors a collection of naughty genes that differ between species and switch on in the testicles.

The genes could play starring roles in sperm production and in the evolution of mammalian species.

“It’s very surprising,” says Jacob Mueller of MIT’s Whitehead Institute for Biomedical Research. “You have this everyday collection of genes that everybody is familiar with, and then you have this mysterious side.”

Female mammals have two copies of the X chromosome, while males have one X and one Y. Biologists have thought since the mid-1960s that the genes on the X chromosome stayed the same as placental mammals diversified. The human X chromosome was sequenced in the early 2000s, and the genes found seemed to support that idea. But Mueller says the patchwork state of the sequence — a mosaic of segments threaded together from 16 donors — raised the possibility that sly genes were slipping under the radar.
Read More

http://www.sciencenews.org/view/generic/id/351813/description/Rogue_gene...