The Vanishing Y Chromosome
The size of the Y chromosome responsible for driving male evolution has decreased significantly over millions of years. This decline has sparked discussions in the scientific community about the future of human sex determination. A research paper published in the Proceedings of the National Academy of Sciences reports that spiny mice have already evolved a new male-determining gene, which could indicate a possible evolutionary path for humans.
A look at developmental changes
Professor Jenny Graves, a geneticist, explains that the reduction in size of the Y chromosome is not a new phenomenon. She explains that in the platypus, the XY chromosome pair looks like ordinary chromosomes with equal members. “This suggests that the mammalian X and Y were a simple pair of chromosomes until very recently,” Graves said. Over the course of 166 million years, the Y chromosome has lost 900 to 55 active genes, a rate that could lead to the complete disappearance of the Y chromosome in about 11 million years.
A new era of sex determination?
As the Y chromosome shrinks, the possibility of a new sex determination gene evolving becomes greater. However, Professor Graves warns that this evolution is fraught with risks. “The evolution of a new sex determination gene comes with risks,” she said. She highlights the possibility of multiple sex determination systems evolving in different parts of the world, leading to the emergence of different human species. As Professor Graves points out, “The 'war' of the sex genes could lead to the isolation of new species, which is exactly what has happened with mole voles and spiny rats.”
The future of human reproduction
The gradual disappearance of the Y chromosome could lead to fundamental changes in human reproduction and significant evolutionary developments. While it is uncertain how this process will unfold, its implications for the future of our species are profound. Scientists continue to investigate these possibilities, recognizing that the disappearance of the Y chromosome could lead to either the development of a new sex-determination system or the emergence of an entirely new human species. As research progresses, the scientific community remains focused on understanding how these changes at the genetic level could affect the future of the human population.