In the past, several studies have talked about a possible situation in which humans may cease to exist on Earth. However, there may be a ray of hope in the form of a study published in the Proceedings of the National Academy of Sciences in 2022. It turns out that the spiny rat, a rodent species from Japan, has evolved a new male-determining gene because its Y chromosome has gone missing.
The Y chromosome is one of the two sex chromosomes that determine the sex of an individual in most mammals, including humans. It is passed from male parents to male offspring. This chromosome contains the SRY gene, which triggers the development of male genitals and turns the embryo into a male, and is also responsible for male fertility. It contains about 100 protein-coding genes, while the X chromosome contains 900.
The study’s author, Australian geneticist Jennifer A. Marshall Graves, says, “The human Y chromosome is running out of time. Over the past 300 million years, it has lost 1393 of its original 1438 genes, and at this rate it will lose the last 45 genes in just 10 million years.” However, according to her 2022 study, things don’t look too bleak for men and society will not turn into a hypothetical Amazonian world where only women exist.
Future
“While the loss of genes on the Y chromosome may seem alarming, it is important to view this change as part of a broader evolutionary journey. As the human genome evolves, it is possible that other chromosomes may eventually take over the role of male sex determination. In fact, some scientists believe that even if the Y chromosome were to disappear completely, other genetic mechanisms may emerge to ensure the continuation of male offspring,” says Dr Vaishali Sharma, senior gynaecologist, MD (AIIMS), infertility specialist.
Moreover, there is evidence from other species too that life can adapt to such changes. “For example, some rodent species have evolved new sex-determination mechanisms and lost their Y chromosomes. These mice have moved genes from the Y chromosome to other chromosomes, enabling them to continue reproducing without the Y chromosome,” says Dr Juhi Patel, obstetrician and gynaecologist at Shalby Hospital.
While it is true that the Y chromosome is decreasing, it does not mean that males are at risk of extinction. Nature finds a way to adapt; therefore, we may see new changes in the definition of sex in the future.
How to reduce the risk?
At the individual level, maintaining a healthy lifestyle can play an important role in maintaining genetic health. “Antioxidant-rich diet, along with avoiding harmful habits such as smoking and excessive alcohol consumption, can help protect DNA and reduce the risk of genetic mutations. These lifestyle choices are beneficial not only for the Y chromosome, but also for overall health and well-being,” says Sharma.
With the development of science and technology, if the Y chromosome faces serious challenges in the future, genetic engineering may provide a solution. Sharma says, “This field has the potential to intervene in cases where the Y chromosome is at risk of being completely destroyed, ensuring that male development can continue uninterrupted. Although such scenarios are hypothetical, the possibilities of genetic engineering offer a sense of hope and security for the future of human genetics.”
