Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cross-species mating may be evolutionarily important and lead to rapid change

08.08.2003


Like the snap of a clothespin, the sudden mixing of closely related species may occasionally provide the energy to impel rapid evolutionary change, according to a new report by researchers from Indiana University Bloomington and three other institutions. Their paper was made available online by Science magazine´s "Science Express" service.



A study of sunflower species that began 15 years ago shows that the sudden mixing and matching of different species´ genes can create genetic super-combinations that are considerably more advantageous to the survival and reproduction of their owners than the gene combinations their parents possess.

"This is the clearest evidence to date that hybridization can be evolutionarily important," said IUB biologist Loren Rieseberg, who led the research. "What´s more, we were able to demonstrate a possible mechanism for rapid evolutionary change by replicating the births of three unusual and ecologically divergent species within an extremely short period of time -- just a few generations."


The finding comes a month after IUB biologist Jeffrey Palmer and colleagues suggested in a letter to Nature that genetic exchange between completely unrelated species has occurred more often than experts previously thought.

There are many modern examples of hybridization in nature, some forced, some natural. Mules are bred by humans from horses and donkeys, are completely sterile, and represent an evolutionary dead-end. But there are other species-crossings that do just fine, such as offspring of the notoriously promiscuous oak tree species, which hybridize so often species-namers commonly joke about not being able to keep up.

Still, cross-species matings usually result in sickness or sterility, if the offspring get that far -- many naturally abort. Hybrid offspring that are fertile but sick or weak will not be able to compete with the purer offspring of either parent in passing on their genes to future generations. As a result, many evolutionary biologists have thought hybridization to be evolutionarily unimportant.

But Rieseberg´s new report suggests that even weak, hybrid offspring can acquire new, strong combinations of genes from their parents. As long as those offspring are just virile enough to transmit their useful genes to their own offspring, those genes may fight their way into populations of either or both parent species and become evolutionarily important. Hybridization has been used to great effect in the creation of successful crops and animal breeds, but many evolutionary biologists have resisted accepting hybridization´s importance in a world before the appearance of modern humans.

"We´re all aware hybridization and intensive cross-breeding has produced better corn and better cows," Rieseberg said. "Yet there´s been resistance in the evolutionary biology community to the notion that evolution might sometimes be facilitated by hybridization."

Rieseberg and his team compared the physical, physiological and genetic traits of several sunflower species. Two of the species, Helianthus annuus and H. petiolaris, are considered "parental," or more ancient. Another three species the scientists studied, H. anomalus, H. deserticola and H. paradoxus, are believed to have evolved somewhat recently, as hybrids of the two parental sunflower species, between 60,000 and 200,000 years ago. The three hybrid species are remarkable in being adapted to very extreme habitats: sand dunes, dry desert floor and salt marshes, respectively. The researchers also created their own hybrids of H. annuus and H. petiolaris.

The researchers found that their synthetic hybrids quickly acquired the traits necessary to colonize the extreme habitats of their naturally evolved hybrid counterparts, suggesting that potentially useful traits can be created quickly. Rieseberg and his team also found that the traits were largely the same as those produced by natural selection during the evolution of the natural hybrid species. Through cross-breeding, the researchers were able to simulate the birth of three new species and the large and dramatic evolutionary changes that accompanied their origins.

"It´s often very easy to explain small differences we see within a species, but harder to account for larger differences between species that require changes in multiple traits or genes," Rieseberg said. "We have provided an explanation for how some of these more difficult changes might happen. Dramatic evolutionary changes are most likely to occur when parental species are very different from each other, creating a much broader array of gene and trait combinations."

Researchers at La Laboratoire de Biologie Moleculaire et Phytochimie (Villeurbanne, France), the University of Georgia and Kent State University also contributed to the report. It was funded by grants from the National Institutes of Health and the National Science Foundation.

David Bricker | Indiana Universty
Further information:
http://www.indiana.edu

More articles from Life Sciences:

nachricht New application for acoustics helps estimate marine life populations
16.01.2018 | University of California - San Diego

nachricht Unexpected environmental source of methane discovered
16.01.2018 | University of Washington Health Sciences/UW Medicine

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

Im Focus: A thermometer for the oceans

Measurement of noble gases in Antarctic ice cores

The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Morbid Obesity: Gastric Bypass and Sleeve Gastrectomy Are Comparable

17.01.2018 | Health and Medicine

Researchers identify new way to unmask melanoma cells to the immune system

17.01.2018 | Health and Medicine

Genetic discovery may help better identify children at risk for type 1 diabetes

17.01.2018 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>