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

'We know that a few of the genes on the Y chromosome are important, such as the ones involved in the formation of sperm, but we also know that most of the genes were not important for survival because they were lost, which led to the very different numbers of genes we observe between the once-identical X and Y.'

Although some of the genes on the Y chromosome have been maintained, most of them have died, and the team found evidence that some others are on track to disappear as well.

'Even though some of the genes appear to be important, we still think there is a chance that the Y chromosome eventually could disappear,' said Makova, according to a PSU release.

'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.'

These findings were published in the Friday issue of PLoS Genetics.