'World where only girls are born': Chromosome associated with male birth found to be shrinking, study reveals

Produced by: Tarun Mishra

Y Chromosome Shrinking

A recent study suggests that the Y chromosome, essential for determining male sex, is gradually shrinking and may eventually disappear, potentially leading to a future where only females are born.

Evolutionary Risks and New Reproductive Mechanisms

The disappearance of the Y chromosome could result in the evolution of a new sex-determining gene or other reproductive mechanisms, with significant implications for human reproduction. A research paper published two years ago in the Proceedings of the National Academy of Sciences reveals how the spiny rat has evolved a new male-determining gene.

Example of the Spiny Rat's Adaptation

The study highlights the spiny rat, which has evolved a new male-determining gene after losing its Y chromosome, raising questions about whether humans could undergo a similar evolutionary process.

Decline of the Human Y Chromosome

The Y chromosome has lost nearly 900 active genes over 166 million years, leaving just 55. Scientists estimate that the remaining genes could disappear in about 11 million years.

Platypus Model

The platypus serves as a model for understanding the Y chromosome's decline, showing that the X and Y chromosomes were once similar and have diverged over time.

Potential for New Sex-Determining Systems

While new sex-determining systems might evolve, this could lead to multiple human species with distinct reproductive mechanisms, posing risks to the continuity of human populations.

Multiple Human Species

The study suggests that millions of years from now, Earth might host several human species with different sex determination systems, or potentially no males at all.

Questions About Long-Term Human Survival

The shrinking Y chromosome raises critical questions about the long-term survival of the human species and the future of reproduction.