The Y Chromosomes is disappearing
According to the Jerusalem Post, Human sex has long been decided by the X and Y chromosomes- females are born with two X chromosomes, whereas males are born with one X and one Y chromosome. That future might be at risk as Y chromosomes continue to gradually disappear across different mammal species, a new study found.
The study, which was published in the peer-reviewed multidisciplinary scientific journal PNAS (Proceedings of the National Academy of Sciences), stated that the evolution of differentiated sex chromosomes has been intensively studied over many decades to address questions, not only about the sex-determining mechanism, but also on the genetic changes to sex chromosomes. A crucial question concerns sex chromosome turnover, whereby a novel sex gene defines a new pair of sex chromosomes, leading to rapid degradation of the sex-specific element. Mammals possess an extremely stable XY chromosome system, in which the Y has almost completely degraded. Exceptional mammals that have recently lost this degraded Y are of unique value for studies of the process of sex chromosome turnover in mammals. Our findings open the way to investigating Y-loss and the earliest evolutionary changes that repurposed an autosome into a new sex chromosome.
The researchers found that the mole voles of eastern Europe and the spiny rats of Japan no longer have Y chromosomes, as they have completely disappeared as a result of evolution and researchers found that humans could be next.
Spiny rats, an endangered species native to several Japanese islands, managed to produce as males and females regardless due to a change in the rat’s chromosome 3. It remains unclear how the mole vole has evolved past Y chromosomes, though researchers will use the discoveries in spiny rats to continue researching.
“The evolution of differentiated sex chromosomes has been intensively studied over many decades to address questions, not only about the sex-determining mechanism but also on the genetic changes to sex chromosomes,” the Tokyo University researchers who authored the study wrote in their abstract. “Mammals possess an extremely stable XY chromosome system, in which the Y has almost completely degraded.”
While the eventual disappearance of Y chromosomes could theoretically lead to the extinction of mankind, evolution could also lead to new sex-defining genes developing and taking precedence over the weakening Y chromosomes.
The question some are asking, are the Y chromosomes already begin to disappear in humans?