Science and Tech


Y Chromosome Not In Danger Of Going Extinct After All

A decade-long study found the mammalian Y chromosome has been stable for millions of years and won't be disappearing any time soon.
Posted at 9:20 PM, Apr 24, 2014

Good news, gentlemen: you are NOT in danger of becoming extinct... anytime soon.

Newly published research out of MIT's Whitehead Institute seeks to put to rest the idea that the Y chromosome within the human genome — the sex-determining chromosome that makes men, well, men — is vanishing.

Wait, you didn't know this was a problem? Maybe one of the best ways to explain this is through two words: shrinkage and monkeys. Stick with me here. 

For starters, each human has 46 chromosomes — 22 matching pairs and one sex-determining pair. That 23rd pair will either be XX, which tells the body to develop female traits, or XY, which means, "Hey, you're a guy!" The Y chromosome is the interesting one here because it's notably smaller than the X chromosome. (Via Flickr / Can H.)

According to Scientific American, the Y chromosome started losing respect because scientists saw it "has only 19 of approximately 600 genes it once shared with the X, 200 to 300 million years ago." Not what you expected when I said shrinkage, right? 

But — and here's where the monkeys come in — a Whitehead Institute spokesman said in a news release, "By comparing the sequence of the human Y chromosome with that of the chimpanzee and the rhesus macaque, the lab discovered that the human Y has lost only one ancestral gene over the past 25 million years. Since then, the Y has been more than holding its own."

David Page, the director if the Whitehead Institute, and other researchers found that the Y chromosomes in humans, chimps, rhesus macaques, marmosets, mice, rats, bulls and opossums all shared "identical ancestral gene content." And there's more. 

Winston Bellott, one of the scientists cited in the research, said the genes in the Y chromosome are important for survival and they've been carefully "selected and purified over time." (Via Nature)

But not everyone is completely on board with the "Y is forever" notion. Jennifer Graves, a geneticist at the Australian National University in Canberra, says the Y chromosome could still disappear in the future, referencing two species of Japanese rats that have lost the chromosome altogether. (Via YouTube / ANUchannel)

But for now, guys, we're good! The researchers of this most recent study say their next endeavor is determining what exactly Y genes do and noting the differences between XX and XY cells. The study is published in the journal Nature