The new findings could bring an end to “unisex” treatment of diseases, allowing sexes to receive different therapies or medicines. Whitehead Institute

Over the course of millions of years of evolution, the human Y chromosome that helps separate males from females has managed to preserve a special set of genes that is essential for the survival of men, a new study says.

While a majority of these Y chromosome genes play hardly any role in sex determination or sperm production, the researchers say that nearly a dozen such genes, which are active in cells and tissue types in the body and are preserved in the Y chromosome, may contribute to differences between men and women with certain diseases.

“This paper tells us that not only is the Y chromosome here to stay, but that we need to take it seriously, and not just in the reproductive tract,” David Page, director of the Whitehead Institute at the Massachusetts Institute of Technology in Cambridge, Mass., said in a statement. “These are genes involved in decoding and interpreting the entirety of the genome.”

Some scientists have previously supported something called a “rotting Y” theory, which argues that because the Y chromosome had lost hundreds of its genes over the past 300 million years of evolution, its extinction is inevitable. But the new study, published in the journal Nature on Wednesday, attempts to prove the "rotting Y" theorists wrong by saying that the Y chromosome is not going anywhere.

The researchers compared the sequence of the human Y chromosome with that of the chimpanzee and the rhesus macaque, and found that the Y has lost only one ancestral gene over the past 25 million years and “has been more than holding its own.”

After showing that the human, chimp and rhesus macaque share a nearly identical ancestral gene, the scientists also mapped the evolution of the Y chromosomes of five more distantly related mammals, including the marmoset, mouse, rat, bull and opossum. A comparison of the ancestral gene of these Y chromosomes revealed a set of broadly expressed genes across all eight species.

“Evolution is telling us these genes are really important for survival,” Winston Bellott, a researcher at the Whitehead Institute and the study’s lead author, said in the statement. “They’ve been selected and purified over time.”

The researchers said that the new findings could bring an end to the “unisex” treatment of diseases, leading men and women to receive different therapies and medicines.