Ladies First: Genes skew sex ratios in evolutionary struggle | Science News



Support credible science journalism.

Subscribe to Science News today.


Ladies First: Genes skew sex ratios in evolutionary struggle

1:30pm, November 7, 2007

Competition among genes within an individual male fruit fly can cause its sperm to produce a high proportion of female offspring. Now, scientists have identified a gene responsible for this well-known phenomenon as well as the gene that later evolved to restore gender balance.

In essence, the two fruit fly genes engage in a tug-of-war in which each succeeds evolutionarily if it can spread widely among future generations.

The imbalance favoring females happens because the sex-skewing gene, called Distorter on the X (Dox), is located on the X chromosome. Females each have two X chromosomes, and pass on only Xs to their offspring. Males each have an X and a Y. They pass an X chromosome to their female offspring and a Y to their male offspring.

To ensure its evolutionary success, Dox somehow sabotages the maturation of sperm carrying Y chromosomes. As a result, a male fruit fly carrying Dox would produce a generation of offspring that is mor

This article is available only to subscribing members. Join the Society today or Log in.

Get Science News headlines by e-mail.

More from Science News

From the Nature Index Paid Content