Featured Research

from universities, journals, and other organizations

Simple Reason Helps Males Evolve More Quickly

Date:
November 16, 2007
Source:
University of Florida
Summary:
Evolutionary biologists have focused on sex differences since Darwin's "Origin of Species." A straightforward but seemingly underappreciated explanation for the ability of males to answer the call of sexual selection may be that their genetic machinery is simpler.

The observation that males evolve more quickly than females has been around since 19th century biologist Charles Darwin noted the majesty of a peacock's tail feather in comparison with the plainness of the peahen's.

Related Articles


No matter the species, males apparently ramp up flashier features and more melodious warbles in an eternal competition to win the best mates, a concept known as sexual selection.

Why males are in evolutionary overdrive even though they have essentially the same genes as females has been a mystery, but an explanation by University of Florida Genetics Institute researchers to appear online in the Proceedings of the National Academy of Sciences this week may shed light on the subject.

"It's because males are simpler," said Marta Wayne, an associate professor of zoology in the College of Liberal Arts and Sciences and director of UF's Graduate Program in Genetics and Genomics. "The mode of inheritance in males involves simpler genetic architecture that does not include as many interactions between genes as could be involved in female inheritance."

The finding may also be useful to scientists studying why diseases may present themselves or respond to treatment differently in men and women.

Researchers examined how gene expression is inherited differently in male and female fruit flies using microarray analysis, which is a way to monitor the activity of thousands of genes simultaneously. The flies were identical genetically, except that females have two X chromosomes and males have a single X and a single Y chromosome.

It turns out that the extra X in females may make answering the call of selection more complicated.

In flies or humans, sex cells from a mother and a father combine to make what eventually becomes an embryo. Females are equipped with two versions of X-linked genes that interact not only with each other, but also with other genes. Males have only one version of the X chromosome, making for fewer interactions and more straightforward male inheritance, especially since the male's Y chromosome contains very few genes.

"In females, a dominant allele can hide the presence of a recessive allele," said Lauren McIntyre, an associate professor of molecular genetics and microbiology in UF's College of Medicine. "In contrast to females, which have two X chromosomes, one inherited from each parent, males have only one X inherited only from their mother. This is a simple mechanism that could be working in cooperation with sexual selection to help males evolve more quickly."

Researchers believe this relatively uncomplicated genetic pathway helps males respond to the pressures of sexual selection, ultimately enabling them to win females and produce greater numbers of offspring.

Relationships between gene expression and modes of inheritance have been addressed before, but this study analyzed an extremely large data set that involved most of the genes in the fruit fly genome, said David Rand, a professor of biology at Brown University who was not involved in the study.

"This research shows how recessive and dominant traits are important in determining variation in populations," Rand said. "The best way to think of it is males play with one card, but females get to play one and hold one. If males have got a good trait, it's promoted; something bad, it's eliminated. In females you can have a bad card, but a good card can protect it. As a result, females can carry deleterious traits but not express them."

UF scientists analyzed 8,607 genes that are shared by both sexes of a fruit fly called Drosophila melanogaster. Of those genes, 7,617 are expressed differently -- meaning the same genes do different things -- in males and females.

Over the years, fruit fly research has helped scientists understand the role of genes in diseases, development, population genetics, cell biology, neurobiology, behavior and evolution. Humans share more than 65 percent of their genes with the fruit fly, including many implicated in certain cancers, Alzheimer's disease and heart disease.

The finding helps explain fundamental processes that may factor into why men and women may show different symptoms or respond differently to diseases.

"There's a health aspect in figuring out differences in gene expression between the sexes," said Wayne. "To make a male or a female, even in a fly, it's all about turning things on -- either in different places or different amounts or at different times -- because we all basically have the same starting set of genes."

The research was supported by a National Institutes of Health grant. Scientists from the University of Nebraska, Ohio University, the University of California Davis and the University of Southern California were also involved in the study.


Story Source:

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


Cite This Page:

University of Florida. "Simple Reason Helps Males Evolve More Quickly." ScienceDaily. ScienceDaily, 16 November 2007. <www.sciencedaily.com/releases/2007/11/071114183253.htm>.
University of Florida. (2007, November 16). Simple Reason Helps Males Evolve More Quickly. ScienceDaily. Retrieved November 25, 2014 from www.sciencedaily.com/releases/2007/11/071114183253.htm
University of Florida. "Simple Reason Helps Males Evolve More Quickly." ScienceDaily. www.sciencedaily.com/releases/2007/11/071114183253.htm (accessed November 25, 2014).

Share This


More From ScienceDaily



More Mind & Brain News

Tuesday, November 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Are Female Bosses More Likely To Be Depressed?

Are Female Bosses More Likely To Be Depressed?

Newsy (Nov. 24, 2014) — A new study links greater authority with increased depressive symptoms among women in the workplace. Video provided by Newsy
Powered by NewsLook.com
Winter Can Cause Depression — Here's How To Combat It

Winter Can Cause Depression — Here's How To Combat It

Newsy (Nov. 23, 2014) — Millions of American suffer from seasonal depression every year. It can lead to adverse health effects, but there are ways to ease symptoms. Video provided by Newsy
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) — Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com
Milestone Birthdays Can Bring Existential Crisis, Study Says

Milestone Birthdays Can Bring Existential Crisis, Study Says

Newsy (Nov. 21, 2014) — Researchers find that as people approach new decades in their lives they make bigger life decisions. Video provided by Newsy
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

 

Health & Medicine

Mind & Brain

Living & Well

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