July 16, 2009

Study: The human Y chromosome may be lost

U.S. scientists say a rapid evolution of the Y chromosome carried only by men has led to a rapid gene loss that might lead to the chromosome's disappearance.

Pennsylvania State University Associate Professor Kateryna Makova, who led the study, and researcher Melissa Wilson compared the DNA of the X and Y chromosomes in different classes of mammals.

The researchers found that DNA of the human Y chromosome began to evolve rapidly 80 million to 130 million years ago. But while DNA on X chromosomes evolved at a constant rate, the rapid evolution of the Y chromosome has resulted in a rapid loss of genes.

Today, the human Y chromosome contains less than 200 genes, while the human X chromosome contains around 1,100 genes, Wilson said.

There is a chance that the Y chromosome eventually could disappear, Makova said. If this happens, it won't be the end of males. Instead, a new pair of non-sex chromosomes likely will start on the path to becoming sex chromosomes.

The research appears in the journal PLoS Genetics.