It's a toxic neighborhood. Even the master sex switch or the genes required for making sperm aren't guaranteed a free ride. If necessary, genes on other chromosomes might take over their jobs, leaving them free to slip into oblivion without taking the human race with them. In fact, the Y chromosome has disappeared in hundreds of other species, Rice said. That isn't the only way DNA can move between chromosomes.
Genes can also jump from one chromosome to a completely different one.
And in the last few years scientists have discovered that during the last 30 million to 50 million years of primate evolution, the Y has been an alluring destination. The immigrants are genes that are essential for making sperm. That makes sense, according to theory, because they would naturally accumulate on a chromosome that appears only in men, where they'd avoid any potential side effects from operating in women. There's new stuff coming on all the time,'' Rice says. Click here for assistance .