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:4/28/2016)... Sweden , April 28, 2016 First ... M (139.9), up 966% compared with the first quarter of 2015 ... profit totaled SEK 589.1 M (loss: 18.8) and the operating margin ... 7.12 (loss: 0.32) Cash flow from operations was SEK ... The 2016 revenue guidance is unchanged, SEK 7,000-8,500 M. ...
(Date:4/15/2016)... 15, 2016  A new partnership announced today ... underwriting decisions in a fraction of the time ... and high-value life insurance policies to consumers without ... With Force Diagnostics, rapid testing (A1C, Cotinine and ... (blood pressure, weight, pulse, BMI, and activity data) ...
(Date:3/31/2016)...   LegacyXChange, Inc. ... LegacyXChange is excited to release its first ... be launched online site for trading 100% guaranteed authentic ... also provide potential shareholders a sense of the value ... industry that is notorious for fraud. The video is ...
Breaking Biology News(10 mins):
(Date:6/24/2016)... ... June 24, 2016 , ... While the majority of commercial spectrophotometers and ... and the 6000i models are higher end machines that use the more unconventional z-dimension ... light beam from the bottom of the cuvette holder. , FireflySci has developed ...
(Date:6/23/2016)... , June 23, 2016 /PRNewswire/ - FACIT ... Ontario biotechnology company, Propellon Therapeutics ... development and commercialization of a portfolio of first-in-class ... Epigenetic targets such as WDR5 represent an exciting ... significantly in precision medicine for cancer patients. Substantial ...
(Date:6/23/2016)... 23, 2016  The Biodesign Challenge (BDC), a university ... to harness living systems and biotechnology, announced its winning ... New York City . ... showcased projects at MoMA,s Celeste Bartos Theater during the ... MoMA,s senior curator of architecture and design, and ...
(Date:6/23/2016)... Apellis Pharmaceuticals, Inc. today announced positive ... its complement C3 inhibitor, APL-2. The trials were ... studies designed to assess the safety, tolerability, pharmacokinetics ... healthy adult volunteers. Forty subjects were ... dose (ranging from 45 to 1,440mg) or repeated ...
Breaking Biology Technology: