While the world is bracing up to fight against another potential pandemic monkeypox after COVID-19, a new concern has been raised for the world. Biologists have flagged a major concern that if it becomes true then the male population can go extinct in the future. Yes! you heard it right. The Y chromosome, which plays a key role in determining male sex in humans, is now disappearing. Over the past 300 million years, it has lost 1,393 of its original 1,438 genes, and only 45 genes remain. According to Jennifer A. Marshall Graves, Distinguished Professor of Genetics and Vice Chancellor's Fellow, the Y chromosome's "time is running out." If this trend continues, the Y chromosome may disappear completely within 11 million years, raising fears about the future of male offspring and human existence.
According to scientific research, the sex of the child in humans and other mammals is determined by a gene located on the Y chromosome, called the male-determining gene. However, the Y chromosome is gradually weakening, and it is likely to disappear completely in a few million years. This could threaten the survival of the human species unless a new sex-determining gene evolves. Already, two mouse species have lost their Y chromosome, but have evolved new genes, which have not affected their survival.
It means there is some hope. A new study published in the Proceedings of the National Academy of Science has revealed that the spiny rat, a rodent species native to Japan, has evolved a new male-determining gene as its Y chromosome disappeared.
What is the Y chromosome?
The Y chromosome plays a key role in determining the sex of males. It works in conjunction with the X chromosome in males. The Y chromosome contains certain genes that control the development of masculinity, causing males to develop special physical characteristics. In humans, women have two X chromosomes, while men have one X and one Y chromosome.
The study says that over 166 million years, the number of active genes in the Y chromosome has decreased from 900 to 55. If this trend continues, the Y chromosome may disappear completely in the next 11 million years. There is debate among scientists on this issue—some believe the Y chromosome will persist indefinitely, while others see it disappearing in a few thousand years.
Despite its size, the Y chromosome carries the all-important SRY gene, which triggers the development of male characteristics in embryos. Around 12 weeks after conception, the SRY activates a genetic pathway that leads to the formation of the testes, which produce the male hormone testosterone, ensuring the baby develops as a male.
As per reports, the SRY gene was discovered in 1990 and was found to trigger SOX9, a gene crucial for male determination across all vertebrates. SOX9 doesn’t reside on the sex chromosomes, but it is activated by the SRY gene, making it essential for male development.