Featured Research

from universities, journals, and other organizations

Manes, Trains And Antlers Explained: How Showy Male Traits Evolved

Date:
August 22, 2008
Source:
University of Wisconsin-Madison
Summary:
For Charles Darwin, the problem of the peacock's tail, in light of his theory of natural selection, was vexing in the extreme. A team of Wisconsin scientists has turned from the question of why such male traits exist to precisely how they evolved. They have worked out the molecular details of how a simple genetic switch controls decorative traits in male fruit flies and how that switch evolved.

A vibrant peacock strutting his stuff.
Credit: iStockphoto/Jennifer Daley

For Charles Darwin, the problem of the peacock's tail, in light of his theory of natural selection, was vexing in the extreme.

Indeed, in 1860, writing to Asa Gray, his most ardent American champion, Darwin confessed: "The sight of a feather in a peacock's tail, whenever I gaze at it, makes me sick!"

In his struggle to explain why such extravagant and seemingly burdensome features existed, the great English naturalist struck upon the idea of sexual selection -- that showy traits such as the Peacock's ornamentation were an advantage in the mating game that outweighed other disadvantages.

A team of Wisconsin scientists has turned from the question of why such male traits exist to precisely how they evolved. They have worked out the molecular details of how a simple genetic switch controls decorative traits in male fruit flies and how that switch evolved. By extension, the work explains the mechanics of how the male lion got his mane, how the bull moose acquired such an impressive set of antlers and, yes, how the peacock got its magnificent tail.

Writing in the latest edition (Aug. 22, 2008) of the journal Cell, a team led by University of Wisconsin-Madison molecular biologist Sean Carroll describes the regulation and evolution of a genetic circuit in fruit flies that permits the male to decorate its abdomen. The work also shows how the regulation of the same genetic circuit in females represses such ornamentation.

"This study is about the how, not the why," says Carroll, a Howard Hughes Medical Institute investigator and one of the world's noted evolutionary biologists. "How can this trait be made in one gender and not the other?"

The question of the origins of secondary sexual characteristics -- traits other than reproductive organs that are peculiar to one gender or another -- is one that dominates modern evolutionary biology, says Thomas Williams, a UW-Madison postdoctoral fellow who helped lead the study. "Males and females basically have the same set of genes, so how do you specifically modify the activity of a male's genes but not a female's genes?"

The answer, according to the new Cell report, resides in the genetic repression of a protein in the male fruit fly that permits it to color the tail end of its abdomen.

"The flies did not need new genes to make a new pattern," Carroll says. "They just changed how males and females use a common set of genes."

The genetic switch that governs expression of the protein, Carroll notes, is ancient and originally evolved for an entirely different purpose, but over time mutations accumulated, perhaps in response to sexual selection, that drove the evolution of male flies with more colorful derrieres.

"The switch existed for tens of millions of years because it had a different job," says Carroll. "But it got remodeled. Evolution is a cumulative process. You have this machinery and it's easy to add a bell or a whistle. With this particular trait, it evolved by exploiting (genetic) information that was already there to make male bodies different from female bodies."

According to Williams and Carroll, the study provided no evidence that the ornamentation process ever occurred in females and was subsequently repressed. "We have enough evidence to believe this evolved in a male-specific way," says Carroll.

The same process, Carroll and Williams argue, is at play in animals from humans and elephant seals to fish and beetles. There is a world of exaggerated traits in animals and evolutionary biologists today, like Darwin 150 years ago, are engaged by the question of what advantages they confer.

"These are the most rapidly evolving traits in evolution," Carroll explains. "If female tastes change, these traits go away. There is no reinforcement.

"It's a tradeoff," Carroll concludes. "As long as the gain outweighs the cost, the feature will survive. The fruit fly's color pattern is a paradigm for understanding how to use the same sets of genes in different sexes to come up with different features."


Story Source:

The above story is based on materials provided by University of Wisconsin-Madison. Note: Materials may be edited for content and length.


Cite This Page:

University of Wisconsin-Madison. "Manes, Trains And Antlers Explained: How Showy Male Traits Evolved." ScienceDaily. ScienceDaily, 22 August 2008. <www.sciencedaily.com/releases/2008/08/080821163848.htm>.
University of Wisconsin-Madison. (2008, August 22). Manes, Trains And Antlers Explained: How Showy Male Traits Evolved. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2008/08/080821163848.htm
University of Wisconsin-Madison. "Manes, Trains And Antlers Explained: How Showy Male Traits Evolved." ScienceDaily. www.sciencedaily.com/releases/2008/08/080821163848.htm (accessed October 21, 2014).

Share This



More Plants & Animals News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

'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
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Goliath Spider Will Give You Nightmares

Goliath Spider Will Give You Nightmares

Buzz60 (Oct. 20, 2014) An entomologist stumbled upon a South American Goliath Birdeater. With a name like that, you know it's a terrifying creepy crawler. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
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