Human Y chromosomes are less chimp, more gorilla

3 Mar 2016

A new method of DNA sequencing has shown that the male-specific Y chromosome in humans has more in common with gorillas than chimpanzees in many ways.

Using two different sequencing technologies – one which produces massive amounts of very short reads, the other that binds them together into long reads – Penn State researchers claim to have developed a “new, less expensive, and faster method” of studying the Y chromosome in all species.

Using this approach, the authors of a new paper in Genome Research have claimed that it could aid studies into male-specific mutations in genes, fertility disorders, and even conservation plans.

More eye-catching, though, is the realisation that gorillas might be closer relations to us than we thought.

“Surprisingly, we found that in many ways the gorilla Y chromosome is more similar to the human Y chromosome than either is to the chimpanzee Y chromosome,” said Penn State’s Kateryna Makova, co-author of the paper.

Jim (on the right), whose Y chromosome was sequenced, together with Dolly, his mother, and Binti, his sister, via San Diego Zoo Global

Jim (on the right), whose Y chromosome was sequenced, together with Dolly, his mother, and Binti, his sister, via San Diego Zoo Global

Time to make a change

Chimpanzees are still our closest relative, which this paper does not dispute, however, Makova found that the chimpanzee Y chromosome appears to have undergone more changes in the number of genes “and contains a different amount of repetitive elements compared to the human or gorilla”.

The difficulties in sequencing the Y chromosome are numerous, including the fact that Y are present in only one copy, and make up just a fraction of the total genetic material found in a cell of a male.

Also, Y are packed full of repetitive sequences, which Makova called “a jigsaw puzzle”.

“Our method will open the door for studying the Y chromosome for more labs, more species, and more individuals within those species.”

To demonstrate how their research could be put to work, the researchers designed genetic markers in the gorilla Y chromosome that allowed them to differentiate the genetic relatedness among male gorillas, which could help with conservation efforts.

Main gorilla image via Shutterstock

Gordon Hunt was a journalist with Silicon Republic

editorial@siliconrepublic.com