Scientists Have Discovered That Males Are Going Extinct

The sex of humans is determined by a special gene found on the Y chromosome, which comes from the father.

However, scientists have observed that the Y chromosome in humans might vanish given enough time. This could pose a threat to our survival unless we adapt by developing a new way to determine sex.

But there’s some hope! Researchers have discovered that similar changes have already occurred in some rodents. Two groups of rodents have successfully adapted after losing their Y chromosomes.

The Simple Science Behind This Discovery

The y chromosome plays a crucial role in determining human sex. unlike females, who have two x chromosomes, males have one x chromosome and a smaller chromosome called y.

The X chromosome contains around 900 genes responsible for various functions unrelated to sex. In contrast, the Y chromosome has fewer genes (about 55) and a significant amount of non-coding DNA, which appears to have no clear function.

Despite its small size, the Y chromosome is essential because it contains a gene that initiates male development during embryonic development. Around 12 weeks after conception, this key gene activates other genes that control the formation of testes.

The developing testes produce male hormones like testosterone, which guide the baby’s development into a male. This pivotal gene, known as SRY (sex-determining region on the Y), was identified in 1990.

SRY works by initiating a genetic pathway that begins with a gene called SOX9, which is critical for male determination across all vertebrates, even though it is not located on sex chromosomes.

Why the Y chromosome is disappearing

The Y chromosome, found in most mammals, typically pairs with the X chromosome and contains essential genes for determining male characteristics. However, this system creates issues due to differences in gene dosage between males and females.

The evolution of this system is peculiar, as evidenced by the platypus, whose sex chromosomes differ greatly from those of most mammals. In platypuses, the XY pair resembles regular chromosomes, unlike the specialized X and Y chromosomes found in other mammals.

This suggests that the mammalian X and Y chromosomes were once similar, regular pairs of chromosomes, not long ago in evolutionary terms. Over millions of years, the Y chromosome has lost a significant number of active genes, with an estimated loss of about five genes per million years.

Based on this rate of gene loss, it’s predicted that the remaining genes on the Y chromosome could disappear entirely within the next 11 million years. This prediction sparked controversy, with varying estimates on the longevity of the human Y chromosome ranging from infinity to a few thousand years.

The future of the males

The future of men is uncertain due to the possible disappearance of the Y chromosome, which is essential for reproduction in humans. This has led to speculation about what may happen to our species.

In some animals like lizards and snakes, females can reproduce without males through a process called parthenogenesis. However, in mammals like humans, certain genes from the father are crucial for reproduction.

The loss of the Y chromosome could potentially lead to the extinction of humans, as it is necessary for sperm production and thus reproduction.

Recent research suggests a possible alternative scenario: humans could evolve a new sex-determining gene to replace the Y chromosome.

But this evolution comes with risks. If different populations evolve different sex determination systems, it could lead to the formation of separate species, as seen in mole voles and spiny rats.

In the distant future, Earth could be inhabited by different human species with distinct sex determination systems, or humans may even disappear altogether.

Not all hope is lost

Two types of rodents have lost their Y chromosome and are still thriving: mole voles in Eastern Europe and spiny rats in Japan.

The mole voles and spiny rats have some species where the Y chromosome and a specific gene called SRY are completely absent. Instead, both sexes have one or two X chromosomes.

Although it’s unclear how mole voles determine sex without the SRY gene, a team led by biologist Asato Kuroiwa from Hokkaido University has made progress with the spiny rat, a group of endangered species on different Japanese islands.

Want to learn more here is the source: https://theconversation.com/men-are-slowly-losing-their-y-chromosome-but-a-new-sex-gene-discovery-in-spiny-rats-brings-hope-for-humanity-195903