Navigation Links
Natural selection at single gene demonstrated

Biologists seeking elusive proof of natural selection at the single-gene level have a powerful new tool at their disposal.

Chris Toomajian, postdoctoral researcher in molecular and computational biology in the USC College of Letters, Arts and Sciences, led a group that sought to replace the standard neutral model, a common but unrealistic test for natural selection, with a statistical method based on hard genomic data.

The group's research will be published online April 25 by Public Library of Science.

"Do we now have enough data to see the standard neutral model wasn't appropriate?" Toomajian asked. "We know something more now about how the population has been structured."

The standard neutral model makes improbable assumptions about population structure, such as assigning each individual an equal chance of reproducing.

Co-author Magnus Nordborg, associate professor of molecular and computational biology in USC College, predicted that earlier research would need to be revisited because the model makes it too easy to infer selection at any given gene.

"Once you start looking at enough cases then you realize that, oops, it's all under selection. I think a lot of that research is going to end up in the trash can," Nordborg said.

The group's method can be applied to any organism, including humans.

The PLoS paper focused on the weed Arabidopsis thaliana, and in particular on the FRIGIDA (FRI) gene, known to influence flowering time.

A. thaliana was once a plant that bloomed annually. But two versions of FRI that appeared thousands of years ago enabled the plant to flower year-round, helping it out-compete other plants.

Toomajian and his group showed that these two versions, also called gene variants, are too common to have spread solely by chance.

"We've shown that for one gene with an important role in that [flowering] process, there's good evidence that there's natural selection changing the behavior of the plants," Toomajian said.

Why the variants were selected remains unclear, though some have suggested that the plant evolved under pressure from the spread of agriculture.

Toomajian's group identified the gene variants through a comparison of 96 plants over 1,102 short fragments of the genome.

Each variant was assigned a score based on the similarity of two plants around the FRI gene relative to their similarity at other regions in the genome.

The higher the score, the less likely it is that a variant could have arisen and spread randomly.

The scoring formula accounts for the greater similarity expected in related plants.

Nordborg said that while natural selection is well documented at the whole-organism level, researchers consider biochemical proof of selection "the Holy Grail" of population genetics.

"What has proven very difficult is to connect specific molecular changes to selection," Nordborg said.

The PLoS paper, along with other recent studies based on intrinsic genomic comparisons, brings biology closer to this goal.


'"/>

Source:University of Southern California


Related biology news :

1. Genetically Modified Natural Killer Immune Cells Attack, Kill Leukemia Cells
2. Natural Killers Could Lead to New Hepatitis Treatments
3. Natural tumor suppressor in body discovered by UCSD medical researchers
4. Naturally occurring asbestos linked to lung cancer
5. Natural compound from pond scum shows potential activity against Alzheimers
6. Natural vitamin E tocotrienol reaches blood at protective levels
7. Natural pine bark extract relieves muscle cramp and pain in athletes and diabetics
8. Natural protein stops deadly human brain cancer in mice
9. Natural anti-viral enzyme helps keep cancer cells alive, researchers find
10. Natural polyester makes new sutures stronger, safer
11. Natural gut hormone offers hope for new obesity drug
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:11/17/2016)...  AIC announces that it has just released a new white paper authored by ... plus high speed data transfer storage solutions. Photo - http://photos.prnewswire.com/prnh/20161116/440463 ... ... ... Setting up a high performance computing or HPC system can ...
(Date:11/14/2016)... CLARA, Calif. , Nov. 14, 2016 ... the biometric identification market, Frost & Sullivan ... Frost & Sullivan Award for Visionary Innovation ... player in the biometric identification market by ... multi-modal verification solution for instant, seamless, and ...
(Date:6/21/2016)... 2016 NuData Security announced today that Randy ... principal product architect and that Jon Cunningham ... development. Both will report directly to Christopher ... reflect NuData,s strategic growth in its product and ... demand and customer focus values. ...
Breaking Biology News(10 mins):
(Date:11/30/2016)... TORONTO , Nov. 30, 2016 /PRNewswire/ - Portage ... Canadian Securities Exchange: PBT.U), is excited to announce ... company focused on developing preclinical ophthalmology assets through ... a potent anti-inflammatory created by Portage Pharmaceuticals Limited ... patients with ocular surface and anterior segment diseases. ...
(Date:11/30/2016)... , Nov. 30, 2016 /PRNewswire/ -  Equicare Health ... solutions, has been recognized as one of the top ... an annual international listing that distinguishes the top digital ... pushed a great step forward this year continually upgrading ... our own customer base and team," says Len ...
(Date:11/30/2016)... 2016   Merck , ein führendes ... einer Reihe von Vereinbarungen mit Evotec AG ... Screeningleistungen für Mercks Palette genetischer Reagenzien wie ... diese Bibliotheken in Kombination mit Evotecs Expertise ... zur Ermittlung und Erforschung neuer Arzneimitteltargets.    ...
(Date:11/30/2016)... ... November 30, 2016 , ... SSCI, the established leader in small-molecule cocrystal ... the latest FDA guidance on pharmaceutical cocrystals as drug substance . The ... , The event follows the successful November 15th event that took place in ...
Breaking Biology Technology: