Featured Research

from universities, journals, and other organizations

Reproduction: Why Having A Mate Provides An Evolutionary Advantage Over Self-fertilization

Date:
October 22, 2009
Source:
University of Oregon
Summary:
OK, it takes two for human reproduction, and now it seems that plants and animals that can rely on either a partner or go alone by self-fertilization give their offspring a better chance for longer lives when they opt for a mate.

Nematode worms (Caenorhabditis elegans).
Credit: Image courtesy of NASA

OK, it takes two for human reproduction, and now it seems that plants and animals that can rely on either a partner or go alone by self-fertilization give their offspring a better chance for longer lives when they opt for a mate.

Related Articles


That's the conclusion gleaned from more than 100 mini-evolution experiments involving nematode worms (Caenorhabditis elegans) at the University of Oregon. Reporting online Oct. 21 in advance of regular publication in the journal Nature, the UO team found that going it alone increases susceptibility to genetic mutations and reduces that adaptability to changing environments.

Sex with self in the animal and plant world is known as selfing. Offspring born from selfing share all of their genes in common with their parent, and each is capable of producing another generation of offspring. Offspring from outcrossing share 50-percent of each parent's genes, and some are born males incapable of bearing offspring.

Selfing populations don't have to deal with pesky males for reproduction. Because males do not produce offspring of their own, selfing populations avoid what biologists call "the evolutionary cost of males," which allows them to increase in size at twice the rate of out-crossing populations. In fact, says UO biology professor Patrick C. Phillips, "biologists going all the way back to Charles Darwin have been puzzled why sexual reproduction via outcrossing exists at all."

Patrick turned to two of his students in the UO Center for Ecology and Evolutionary Biology, which he heads, to explore what good comes from these worms having partners.

Graduate student Levi T. Morran and Michelle D. Parmenter, an undergraduate student from Eugene, conducted more than 100 trials in which populations of nematodes -- also known as roundworms -- were adapted to new environments, including to the presence of a bacterial pathogen that eats the worms from the inside out. The students, under Patrick's guidance, genetically engineered the worms, which normally practice a combination of both selfing and outcrossing, to reproduce either just by selfing or just by outcrossing. They tracked the evolution of 60 different populations for 50 generations under different combinations of mutation, mating system and genetic background.

They found that purely selfing populations were much more susceptible to accumulating harmful mutations and were not able adapt to rapidly changing environments. Traditional thinking has suggested that selfing populations are able to purge many of these mutations, but this study found that the ability to sufficiently purge was overwhelmed by slight increases in mutation rates. That, in turn, threatens the long-term survival of selfing roundworms.

"The inability of selfing populations to adapt to changing environmental conditions helps to explain the observation that selfing populations are much more likely to go extinct than outcrossing populations," said Morran, who was the study's lead author.

While males may be problematic for a wide variety of reasons, from an evolutionary point of view, their benefits outweigh their costs, which helps to explain why having sex with others is the rule rather than the exception within natural populations, Phillips said.

"Many scientists have argued that outcrossing has evolved to avoid the genetic consequences of inbreeding, while others have emphasized the role that outcrossing plays in generating the genetic variation necessary for evolutionary change," he added. "Our work shows that both of these factors are important."

Three grants from the National Science Foundation helped support the research. Morran also was funded by a National Institutes of Health genetics fellowship.

Morran, Parmenter and Phillips were coauthors of the paper.


Story Source:

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


Cite This Page:

University of Oregon. "Reproduction: Why Having A Mate Provides An Evolutionary Advantage Over Self-fertilization." ScienceDaily. ScienceDaily, 22 October 2009. <www.sciencedaily.com/releases/2009/10/091021133856.htm>.
University of Oregon. (2009, October 22). Reproduction: Why Having A Mate Provides An Evolutionary Advantage Over Self-fertilization. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2009/10/091021133856.htm
University of Oregon. "Reproduction: Why Having A Mate Provides An Evolutionary Advantage Over Self-fertilization." ScienceDaily. www.sciencedaily.com/releases/2009/10/091021133856.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
Monarch Butterflies Descend Upon Mexican Forest During Annual Migration

Monarch Butterflies Descend Upon Mexican Forest During Annual Migration

Reuters - Light News Video Online (Dec. 19, 2014) Millions of monarch butterflies begin to descend onto Mexico as part of their annual migration south. Rough Cut (no reporter narration) Video provided by Reuters
Powered by NewsLook.com
Birds Might Be Better Meteorologists Than Us

Birds Might Be Better Meteorologists Than Us

Newsy (Dec. 19, 2014) A new study suggests a certain type of bird was able to sense a tornado outbreak that moved through the U.S. a day before it hit. Video provided by Newsy
Powered by NewsLook.com
Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
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