FLICKR, COLM MCMULLANThe most accurate sequencing of the X chromosome to date has revealed that the sex chromosome, thought to be the most stable of all the chromosomes, is loaded with regions of rapidly evolving genes. Even more surprising, the chromosome, considered to the female counterpart of the male-associated Y chromosome, may play a role in male infertility and sperm production. The findings are reported today (July 21) in Nature Genetics.
“The big surprise is that the X chromosome in both humans and mice has been evolving towards a kind of male specialization,” said senior author David Page, a geneticist at the Whitehead Institute at the Massachusetts Institute of Technology. “This flies in the face of a deep-seated, even if not scientifically substantiated, view that the X chromosome is female leaning.”
Page’s team initiated a study of the X chromosome as a means to test a prediction made by geneticist Susumu Ohno in the 1960s and backed up by nearly 15 years of comparative gene mapping studies: that X-linked genes would vary little among mammals. The rationale of the prediction—dubbed Ohno’s Law—is that translocation of genes between the X chromosome and autosomes would interfere with sex ...
