Featured Research

from universities, journals, and other organizations

Why Sex Chromosomes Evolve So Rapidly

Date:
October 22, 2007
Source:
Santa Fe Institute
Summary:
The mechanisms that determine sex in animals vary widely, involving actions of different sets of genes on different chromosomes. According to a new article this can be explained by linking sex determination genes to genes that increase survival rates in one sex at the expense of the other.

In animals with separate sexes, embryos commit to becoming male or female at an early stage. Often this key decision is made by sex determination genes on the sex chromosomes. The genes involved in sexual development have changed remarkably little during evolution. In contrast, the sex determination genes and the sex chromosomes themselves are among the most rapidly changing features of the genome.

A research team formed by Sander van Doorn (Santa Fe Institute, USA) and Mark Kirkpatrick (University of Texas at Austin, USA) suggests an answer to the puzzle of why sex chromosomes evolve so rapidly.

In a theoretical study published in the October 17, 2007 issue of Nature they demonstrate that sexual conflict can establish novel sex-determining genes and sex chromosomes. The proposed mechanism extends the established theory on the origin of sex chromosomes, and it explains how sex determination can move from an ancestral sex chromosome to an autosome, a non-sex-chromosome, that then invades to become a new sex chromosome.

The mechanism suggested by these authors begins with an autosome that carries two genes with particular features. One of these two genes is under sexually antagonistic selection. This means that some versions of the gene (alleles) are more beneficial in males than in females, while other alleles are more beneficial for females.

The other gene influences the sex of the individual. Natural selection produces an association between the two genes -- an allele that is most beneficial in males will occur most often with the allele of the other gene that makes the individual male. It is then possible that this new male-making, male-benefiting (or female-making, female-benefiting) combination of genes spreads through the population, eventually replacing the old pair of sex chromosomes.

Genes with sexually antagonistic fitness effects and mutations that influence sex determination appear to be common in nature, but how would we know if the model presented here actually caused a change in the sex-determination mechanism in a particular species?

One possible test would look at sexually antagonistic genes on a chromosome immediately before and after that chromosome took over the role of sex determination.

This might be possible by comparing closely related species with different sex chromosomes. One species would have a very young set of sex chromosomes, while the other would still use the old sex chromosomes, and might approximate the state of the chromosome right before the switch.


Story Source:

The above story is based on materials provided by Santa Fe Institute. Note: Materials may be edited for content and length.


Cite This Page:

Santa Fe Institute. "Why Sex Chromosomes Evolve So Rapidly." ScienceDaily. ScienceDaily, 22 October 2007. <www.sciencedaily.com/releases/2007/10/071019131411.htm>.
Santa Fe Institute. (2007, October 22). Why Sex Chromosomes Evolve So Rapidly. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2007/10/071019131411.htm
Santa Fe Institute. "Why Sex Chromosomes Evolve So Rapidly." ScienceDaily. www.sciencedaily.com/releases/2007/10/071019131411.htm (accessed October 22, 2014).

Share This



More Plants & Animals News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Cadaver Dogs Aid Search for More Victims of Suspected Indiana Serial Killer

Cadaver Dogs Aid Search for More Victims of Suspected Indiana Serial Killer

Reuters - US Online Video (Oct. 21, 2014) Police in Gary, Indiana are using cadaver dogs to search for more victims after a suspected serial killer confessed to killing at least seven women. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
White Lion Cubs Unveiled to the Public

White Lion Cubs Unveiled to the Public

Reuters - Light News Video Online (Oct. 21, 2014) Visitors to Belgrade zoo meet a pair of three-week-old lion cubs for the first time. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
'Cadaver Dog' Sniffs out Human Remains

'Cadaver Dog' Sniffs out Human Remains

AP (Oct. 21, 2014) Where's a body buried? Buster's nose can often tell you. He's a cadaver dog, specially trained to find human remains and increasingly being used by law enforcement and accepted in courts. These dogs are helping solve even decades-old mysteries. (Oct. 21) Video provided by AP
Powered by NewsLook.com
White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins