Featured Research

from universities, journals, and other organizations

Survival Of The Rarest: Fruit Flies Shed Light On The Evolution Of Behavior

Date:
May 9, 2007
Source:
University of Toronto
Summary:
Sometimes, it pays to be rare--think of a one-of-a-kind diamond, a unique Picasso or the switch-hitter on a baseball team. Now, new research suggests that being rare has biological benefits.

Fruit fly larvae used by Mark Fitzpatrick in his research.
Credit: Image courtesy of University of Toronto

Sometimes, it pays to be rare--think of a one-of-a-kind diamond, a unique Picasso or the switch-hitter on a baseball team.

Related Articles


Now, new research suggests that being rare has biological benefits. Professor Marla Sokolowski, a biologist at the University of Toronto Mississauga who in the 1980s discovered that a single gene affects the foraging behaviour of fruit flies, has identified the benefit of rarity in populations of fruit flies with two different versions of the foraging gene. This gene is of particular interest because it is also found in many organisms, including humans.

"There's considerable genetic variation in nature and we haven't been able to explain why it persists, since natural selection ensures that only the best survive," says Sokolowski, who holds a Canada Research Chair in Genetics. "In some cases, individuals with characteristics that differ from the rest of the population are more likely to survive since their rarity makes them less conspicuous to predators. However, to date we haven't understood this type of survival advantage at the level of the gene."

The findings involve a phenomenon known as "negative frequency-dependent selection." Essentially, it suggests that rare variants have a better chance of survival--just as a rare strain of the flu has a better chance of spreading through a population that is already immune to more common strains of the virus. In this case, flies carry one of two versions of the foraging gene (either the "rover" or "sitter" type). Rover larvae move around more than sitter larvae while feeding and they are also more likely to explore new food patches than sitters. The researchers explored the evolutionary mechanism that favours the persistence of both of these types in nature.

Doctoral student Mark Fitzpatrick raised colonies of flies with different ratios of rovers to sitters and different concentrations of nutrients in their food, and assessed their fitness--how many survived to the end of their larval stage. To distinguish between the rovers and the sitters, which are physically identical, Fitzpatrick "tagged" one of the types with a green fluorescent protein that glows under ultraviolet light. Then, over the course of a year, Fitzpatrick sat in a darkened room for several hours a day counting glowing larvae under a microscope.

The researchers found that when the fruit fly larvae were competing for food, those that did best had a version of the foraging gene that was rarest in a particular population. For example, rovers did better when there were lots of sitters, and sitters did better when there were more rovers.

"If you're a rover surrounded by many sitters, then the sitters are going to use up that patch and you're going to do better by moving out into a new patch," says Sokolowski. "So you'll have an advantage because you're not competing with the sitters who stay close to the initial resource. On the other hand, if you're a sitter and you're mostly with rovers, the rovers are going to move out and you'll be left on the patch to feed without competition."

More generally, Fitzpatrick says these results may help explain why genetic variants such as these are common in nature. "In the case of fruit flies, one variant encourages the survival of the other. In essence, there is not one best type of fly," he says. If this process is common in nature, it may offer one explanation for why individuals, in general, vary so much from one to another in almost all species.

The new study appears in the May 10 issue of the journal Nature. The researchers' next step is to show that this phenomenon is also taking place in the wild. In addition, since the foraging gene is found in many animals, including honeybees, mice and humans, the researchers are examining how variations in the human foraging gene may be linked to food-related disorders.

The research was funded by grants from the Natural Sciences and Engineering Research Council of Canada and the Canada Research Chairs program to Sokolowski and fellow author Locke Rowe--a biology professor at the University of Toronto.


Story Source:

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


Cite This Page:

University of Toronto. "Survival Of The Rarest: Fruit Flies Shed Light On The Evolution Of Behavior." ScienceDaily. ScienceDaily, 9 May 2007. <www.sciencedaily.com/releases/2007/05/070509161159.htm>.
University of Toronto. (2007, May 9). Survival Of The Rarest: Fruit Flies Shed Light On The Evolution Of Behavior. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2007/05/070509161159.htm
University of Toronto. "Survival Of The Rarest: Fruit Flies Shed Light On The Evolution Of Behavior." ScienceDaily. www.sciencedaily.com/releases/2007/05/070509161159.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Earthworms Provide Cancer-Fighting Bacteria

Earthworms Provide Cancer-Fighting Bacteria

Reuters - Innovations Video Online (Dec. 21, 2014) Polish scientists isolate bacteria from earthworm intestines which they say may be used in antibiotics and cancer treatments. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Reuters - Innovations Video Online (Dec. 21, 2014) A team of scientists led by Danish chemist Jorn Christensen says they have isolated two chemical compounds within an existing antipsychotic medication that could be used to help a range of failing antibiotics work against killer bacterial infections, such as Tuberculosis. Jim Drury went to meet him. Video provided by Reuters
Powered by NewsLook.com
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

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