Navigation Links
Genome duplication encourages rapid adaptation of plants
Date:5/3/2011

Plants adapt to the local weather and soil conditions in which they grow, and these environmental adaptations are known to evolve over thousands of years as mutations slowly accumulate in plants' genetic code. But a University of Rochester biologist has found that at least some plant adaptations can occur almost instantaneously, not by a change in DNA sequence, but simply by duplication of existing genetic material.

Justin Ramsey's findings are published in the current Proceedings of the National Academy of Sciences.

While nearly all animals have two sets of chromosomesone set inherited from the maternal parent and the other inherited from the paternal parentmany plants are polyploids, meaning they have four or more chromosome sets. "Some botanists have wondered if polyploids have novel features that allow them to survive environmental change or colonize new habitats," says Assistant Professor Justin Ramsey. "But this idea had not been rigorously tested."

Plant breeders have previously induced polyploidy in crop plants, like corn and tomato, and evaluated its consequences in greenhouses or gardens. Such an experimental approach had never been taken in wild plant species, Ramsey said, so it was unknown how polyploidy affected plant survival and reproduction in nature.

Ramsey decided to perform his own test by studying wild yarrow (Achillea borealis) plants that are common on the coast of California. Yarrow with four chromosome sets (tetraploids) occupy moist, grassland habitats in the northern portion of Ramsey's study area; yarrow with six sets of chromosomes (hexaploids) grow in sandy, dune habitats in the south.

Ramsey transplanted tetraploid yarrow from the north into the southern habitat and discovered that the native hexaploid yarrow had a five-fold survival advantage over the transplanted tetraploid yarrow. This experiment proved that southern plants are intrinsically adapted to dry conditions; however, it was unclear if the change in chromosome number, per se, was responsible. Over time, natural hexaploid populations could have accumulated differences in DNA sequence that improved their performance in the dry habitats where they now reside.

To test that idea, Ramsey took first-generation, mutant hexaploid yarrow that were screened from a tetraploid population, and transplanted them to the sandy habitat in the south. Ramsey compared the performance of the transplanted yarrows and found that the hexaploid mutants had a 70 percent survival advantage over their tetraploid siblings. Because the tetraploid and hexaploid plants had a shared genetic background, the difference of survivorship was directly attributable to the number of chromosome sets rather than the DNA sequences contained on the chromosomes.

Ramsey offers two theories for the greater survivorship of the hexaploid plants. It may be that DNA content alters the size and shape of the cells regulating the opening and closing of small pores on the leaf surface. As a result, the rate at which water passes through yarrow leaves may be reduced by an increase in chromosome set number (ploidy). Another possibility, according to Ramsey, is that the addition of chromosome sets masks the effects of plant deleterious genes, similar to those that cause cystic fibrosis and other genetic diseases in humans.

"Sometimes the mechanism of adaptation isn't a difference in genes," said Ramsey, "it's the number of chromosomes." While scientists previously believed polyploidy played a role in creating gene familiesgroups of genes with related functionsthey were uncertain whether chromosome duplication itself had adaptive value.

Now, Ramsey says scientists "should pay more attention to chromosome number, not only as an evolutionary mechanism, but as a form of genetic variation to preserve rare and endangered plants."


'/>"/>

Contact: Peter Iglinski
peter.iglinski@rochester.edu
585-273-4726
University of Rochester
Source:Eurekalert

Related biology news :

1. NC State researchers get to root of parasite genome
2. Worm genome offers clues to evolution of parasitism
3. Complete Genomics launches, becomes worlds first large-scale human genome sequencing company
4. Diatom genome helps explain success in trapping excess carbon in oceans
5. Washington University scientists first to sequence genome of cancer patient
6. Research consortium to sequence turkey genome
7. DOE Joint Genome Institute completes soybean genome
8. Breast cancer genome shows evolution, instability of cancer
9. In lung cancer, silencing one crucial gene disrupts normal functioning of genome
10. Gene switch sites found mainly on shores, not just islands of the human genome
11. Genome Medicine: Bridging the gap between research and clinical practice
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/27/2016)... 27, 2016 Research and Markets has announced ... report to their offering. ... to grow at a CAGR of 12.28% during the ... on an in-depth market analysis with inputs from industry experts. The ... coming years. The report also includes a discussion of the key ...
(Date:6/22/2016)... , June 22, 2016  The American College of ... Trade Show Executive Magazine as one of the fastest-growing ... May 25-27 at the Bellagio in Las Vegas ... the highest percentage of growth in each of the following ... exhibiting companies and number of attendees. The 2015 ACMG Annual ...
(Date:6/22/2016)... 2016   Acuant , the leading ... has partnered with RightCrowd ® to ... Management, Self-Service Kiosks and Continuous Workforce Assurance. ... functional enhancements to existing physical access control ... with an automated ID verification and authentication ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... 2016  Alex,s Lemonade Stand Foundation (ALSF), a leading ... open a state-of-the-art bioinformatics lab, using ,big data, to ... comes as Liz Scott , co-executive director of ... Summit in Washington, D.C. , hosted ... and advocate of pediatric cancer research and awareness. ...
(Date:6/27/2016)... June 27, 2016  Global demand for enzymes ... through 2020 to $7.2 billion.  This market includes ... cleaning products, biofuel production, animal feed, and other ... and biocatalysts). Food and beverages will remain the ... increasing consumption of products containing enzymes in developing ...
(Date:6/27/2016)... GUELPH, ON , June 27, 2016 /PRNewswire/ - BIOREM ... it has been advised by its major shareholders, Clean ... LP, United States based venture ... common shares of Biorem (on a fully diluted, as ... for the disposition of their entire equity holdings in ...
(Date:6/27/2016)... SAN DIEGO , June 27, 2016  Sequenom, ... company committed to enabling healthier lives through the development ... Supreme Court of the United States ... Federal courts that the claims of Sequenom,s U.S. Patent ... the patent eligibility criteria established by the Supreme Court,s ...
Breaking Biology Technology: