Two new studies of the evolutionary history of the Y chromosome show that, contrary to popular (if not scientific) belief, the male is not at risk of dying out.
The Y chromosome which, among other things, instructs the human fetus to develop male sex organs instead of defaulting to female ones, is significantly shorter than the X chromosome and has lost hundreds of genes over the last several millions years. This has lead to the fear that the Y chromosome is in danger of disappearing completely, and with it, the future of man.
The new research, published in the scientific journal Nature, puts that theory firmly to rest. According to Whitehead Institute Director David Page, whose team contributed research to the study, the Y chromosome stopped shedding genes millions of years ago. Matt Fearer, Whitehead's director of communications and public affairs explains in a press release:
The loss of genetic content on the Y is not in dispute. In fact, a recent study from Page’s own lab showed that the human Y chromosome retains only 19 of the more than 600 genes it once shared with its ancestral autosomal partner, the X chromosome. However, 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.
The new research further shows that the Y chromosome could play a larger genetic role than previously thought. Again, Fearer explains:
The vast majority of these tenacious [surviving] genes appear to have little if any role in sex determination or sperm production... [these findings] suggest that because these Y-linked genes are active across the body, they may actually be contributing to differences in disease susceptibility and severity observed between men and women.
Page notes that the research is a jumping off point for further investigation into how the Y chromosome functions, saying:
There are approximately a dozen genes conserved on the Y that are expressed in cells and tissue types throughout the body... These are genes involved in decoding and interpreting the entirety of the genome. How pervasive their effects are is a question we throw open to the field, and it’s one we can no longer ignore.
The New York Times adds that the research could reveal new discrepancies between male and female biology:
Differences between male and female tissues are often attributed to the powerful influence of sex hormones. But now that the 12 regulatory genes are known to be active throughout the body, there is clearly an intrinsic difference in male and female cells even before the sex hormones are brought into play.
Congratulations, men. You're going to make it after all.