Male Y Chromosome Extinction Theory Challenged
Men may not become extinct after all, according to a new study. Previous research has suggested the Y sex chromosome, which only men carry, is decaying genetically so fast that it will be extinct in five million years’ time. A gene within the chromosome is the switch which leads to testes development and the secretion of male hormones. But a new U.S. study, published in Nature suggests the genetic decay has all but ended.
The domsday predictions were based on comparisons between the human X and Y sex chromosomes. While these chromosomes were once thought to be identical far back in the early history of mammals, the Y chromosome now has about 78 genes, compared with about 800 in the X chromosome.