Testis size matters for genome evolution

March 5, 2014

In many primates, females mate with multiple partners, causing an often-intense competition amongst males to pass along their DNA to be king of the genome as well as the jungle.

In the advanced online edition of Molecular Biology and Evolution, author Alex Wong used a published sequence dataset from 55 species of primates to test for a correlation between molecular evolutionary rates across a genome (substitution rates) and testes weights, used in the study as a proxy for increased sperm production and competition. It is widely thought that the production of increased numbers of sperm results from more rounds of cell division ——and with more cell division, more mutations arise during .

"In general, the speed of genome evolution is higher for species in which males have large testes in comparison to species in which males have small testes," said Wong. "This finding helps us to understand why genomes evolve at different rates in different species, and has implications for our understanding of the relationship between and the overall fitness of a population."

Wong applied a sophisticated evolutionary method to detect a correlation between testes size and substitution rate in primates, and found a positive correlation when accounting for other confounding factors. This finding could provide support for the general prediction that should result in higher substitution rates as a consequence of higher spermatogenic activity in that mate with more than one male.

"The current finding of covariance between competition intensity and substitution rates adds to a growing body of knowledge concerning the sources of substitution rate variation," said Wong. "The extent to which this covariance is widespread is not yet clear; application of robust comparative methods to large phylogenetic datasets in other taxa, such as birds and insects, will help to establish its generality."

Explore further: Which species has the largest testicles? Big secret revealed by researchers

Related Stories

'Paranoia' about rivals alters insect mating behavior

August 8, 2011

Scientists at the University of Liverpool have found that male fruitflies experience a type of 'paranoia' in the presence of another male, which doubles the length of time they mate with a female, despite the female of the ...

Guppies lie about mate choice to trick rivals

September 9, 2013

When it comes to sex among guppies, competition is high for those at the top of the game. To get around this predicament, a recent study has shown, guppies use trickery.

Big sperm don't always win the race

January 31, 2014

When females mate with more than one male, each one's sperm has to compete to get to her eggs. Until now, researchers had thought the fastest sperm would dominate.

All sperm are not equal

February 13, 2014

An experimental study from researchers at Uppsala University provides evidence that in Atlantic salmon, selection acting upon sperm phenotypes within a single ejaculate of a male affects the time until hatching in the resulting ...

Recommended for you

Sixth sense: How do we sense electric fields?

October 13, 2015

A variety of animals are able to sense and react to electric fields, and living human cells will move along an electric field, for example in wound healing. Now a team lead by Min Zhao at the UC Davis Institute for Regenerative ...

A better way to read the genome

October 9, 2015

UConn researchers have sequenced the RNA of the most complicated gene known in nature, using a hand-held sequencer no bigger than a cell phone.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.