Study Finds 'Y' Chromosomes Are Shrinking - Decoding What It Really Means

A scientific research revealed a shrinkage in 'Y' chromosomes, which is primarily responsible for male sex determination. The study by the University of Kent detailed that over the years, the Y chromosome has had a limited gene repertoire, shrivelling and degenerating slowly. These findings have been going viral on social media, leaving people questioning whether males will 'go extinct' in the future. However, scientists clarified what exactly this means.

What Happens If Y Chromosomes Shrink?

Humans have 23 pairs of chromosomes, 22 of which are autosomes, and one pair determines sex: XX for females and XY for males. However, a recent study published in the ‘Proceedings of the National Academy of Science’ showed that the number of genes on the Y chromosome is gradually shrinking over millions of years.

The Y chromosome has become notably smaller than the X chromosome and contains approximately 50 to 200 genes compared to the 1,000 genes on the X, altering human reproduction over generations. According to research, this shrinkage may eventually affect male fertility, reducing the number of critical genes involved.

Scientists state that this reduction in the Y chromosome is partly due to limited recombination with the X chromosome, meaning the Y cannot repair genetic damage as effectively. Over time, mutations accumulate, and some genes are lost. Moreover, evolutionary pressures also render some genes redundant.

However, scientists stated that this is not a sign that the male species is in immediate danger or any other cause for alarm. Although the Y chromosome plays a crucial role in spermatogenesis and the development of male traits, experts state that the reduction in its size does not currently impact male fertility in the near future.

Some studies report that evolutionary history shows that some species have already lost their Y chromosome but developed alternative methods for sex determination. For example, a recent Dutch study uncovered that the Japanese spiny rat has lost its Y chromosome, evolving a new gene to determine sex.