Y chromosome is Not Disappearing, Researchers Say

Men are not about to disappear and it's time science starts taking the human Y chromosome seriously, researchers say.

The Y-chromosome is one of the two sex chromosomes in human beings. It has 59 million building blocks of DNA and is inherited exclusively by the male line.

Many scientists believe that the Y-chromosome has limited days because it has lost several genes.

The new study by researchers at Whitehead Institute for Biomedical Research in Cambridge, Massachusetts, has found that the Y-chromosome has remained stable in the past 25 million years. Their study also shows that the male-chromosome affects cells present in different parts of the body and not just the sexual organs.  

"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," said David Page, Whitehead Institute Director whose lab conducted the research, according to a new release.

"There are approximately a dozen genes conserved on the Y that are expressed in cells and tissue types throughout the body," he explained. "These are genes involved in decoding and interpreting the entirety of the genome. How pervasive their effects are is a question we throw open to the field, and it's one we can no longer ignore."

The study challenges the idea that the Y-chromosome is doomed, but doesn't argue that the chromosome has lost a lot of genetic material. Page's own lab recently found that the Y-chromosome has just 19 genes of the 600 genes that it once shared with its partner, the X chromosome. However, comparison of the chromosome with that of chimpanzee and the rhesus macaque showed that the human Y has lost just one gene in the past 25 million years.

In the present study, the team mapped the evolution of the human Y chromosome using genetic information from five mammals; the marmoset, mouse, rat, bull, and opossum. Researchers looked at the ancestral part of the chromosome and found that several of the genes were active in the animals included in the study.

According to Page, these conserved genes are elite.                   

"Evolution is telling us these genes are really important for survival," added Winston Bellott, a research scientist who worked on the study. "They've been selected and purified over time."

In the next part of the study, researchers will try to find what this elite group of genes does.

The study is published in the journal Nature and was supported by National Institutes of Health and the Howard Hughes Medical Institute.

Another study conducted by Henrik Kaessmann of the University of Lausanne, also published in the journal Nature, deconstructed the evolution of the Y chromosome. The team found that the chromosome affects several parts of the male human body.