Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fossils reveal direct link between global warming and genetic diversity in wildlife

08.09.2004


For the first time, scientists have found a direct relationship between global warming and the evolution of contemporary wildlife. A research team led by Stanford University biologist Elizabeth A. Hadly published its findings in the Sept. 7 online edition of the journal PloS Biology.



"We think we know a lot about how animals might respond to global warming, but we really have very little idea about their actual genetic response to environmental change," said Hadly, an assistant professor of biological sciences at Stanford.

In the study, she and her colleagues conducted a genetic analysis of two species of rodents commonly found in Wyoming’s Yellowstone National Park – the montane vole (Microtus montanus) and the northern pocket gopher (Thomomys talpoides). The researchers collected DNA from living animals and from the teeth of fossilized specimens whose remains were buried in Lamar Cave, a remote site near the northeast entrance to the park. "The deposit in the cave is about nine yards deep and it took me seven years to excavate and identify the fossils," Hadly said. "It contains hundreds of thousands of bones and represents a continuous fossil record dating back 3,000 years. This timescale allows us to really investigate microevolution in a natural environment, the way you’d investigate it in a laboratory with something that has a much quicker generational timeline, such as bacteria or fruit flies."


Climate change and genetics

For the experiment, the research team compared DNA from voles and pocket gophers living near Lamar Cave with ancient DNA from fossilized rodents that inhabited the area at different times since 1000 B.C. The researchers were particularly interested in animals that were alive during two recent climatic events – the Medieval Warm Period (850-1350 A.D.), when the Northern Hemisphere experienced a slight warming trend; and the Little Ice Age (1350-1950), when the hemisphere cooled.

Since voles and pocket gophers prefer relatively wet grasslands, the scientists expected to see a decline in the population of both species during the Medieval Warm Period when their habitats dried up, and an increase during the Little Ice Age when the climate was wetter.

That prediction was confirmed by an analysis of fossil abundance in Lamar Cave, which revealed a 40 percent drop in the vole population during the warmer period, along with a 50 percent decline in the number of pocket gophers. As expected, fossil abundance for both species rose dramatically during the Little Ice Age as precipitation levels increased. These findings established a direct correlation between climate change and population size, but how did individual voles and pocket gophers respond genetically to these episodes of global warming and cooling?

Earlier studies have shown that, when an isolated population shrinks, inbreeding increases. As a result, surviving offspring end up with similar DNA. Over time, this lack of genetic diversity can jeopardize the entire population, because each individual inherits the same vulnerability to diseases and other external threats. "When you decrease population size, you have the potential of eliminating much genetic diversity," Hadly explained. "That’s what happened to pocket gophers during the Medieval Warm Period. We found that they underwent a population size reduction and a decline in genetic diversity, which is what you would predict."

But voles had a different response to medieval warming. "They didn’t show any reduction in genetic diversity, even though they did show a reduction in population size," Hadly said. That’s because voles routinely look for mates from other colonies. "Voles move around," Hadly noted. "They disperse quite freely, and that actually results in an elevation of genetic diversity during the time that their population sizes are undergoing reduction. Pocket gophers, on the other hand, are subterranean rodents. They dig underground burrows that are very energetically expensive to build, and they kind of stick in one place."

Subtle message

These results have important implications for wildlife biology and conservation, Hadly observed. "There’s a subtle message in this paper about the potential influence of warming on evolution," she said. "Voles show an influx of new genes and genetic diversity as their population declines, which means they’re connected to other populations. But gophers haven’t really recovered from the Medieval Warm Period, which ended less than 1,000 years ago. That means gophers are not getting any fresh, new genes from somewhere outside because they’re isolated."

While previous studies have shown that interbreeding usually occurs among large populations of animals, "this study shows that gene flow is occurring when population sizes are low," Hadly said. "So the snapshot we have today about how populations are connected may not be how it actually persists through time."

The study also has implications for wildlife managers in the greater Yellowstone ecosystem who are trying to maintain genetically diverse populations of elk, bison and other mammals. "The landscape of Yellowstone – arguably one of the largest relatively intact temperate zone ecosystems in the world – is really chopped up and isolated, and there are fewer connections between populations," Hadly explained. "They really might not have anyplace to go because of development or habitat loss, and this has the potential to be exacerbated during global warming."

She noted that the methods developed for the study offer wildlife biologists a unique approach to understanding the long-range effects of climate change on genetics. "In looking at wild organisms in nature, I don’t really know of another study like this," she said. "No one has really looked specifically at how the environment has influenced genes over a 3,000-year timescale. And our expectation is that other species will also show genetic responses to warming. Whether these effects are reversible may have to do with life history and how connected populations are, and for many species that remains to be seen."

Mark Shwartz | EurekAlert!
Further information:
http://www.stanford.edu

More articles from Life Sciences:

nachricht Designer cells: artificial enzyme can activate a gene switch
22.05.2018 | Universität Basel

nachricht Flow of cerebrospinal fluid regulates neural stem cell division
22.05.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Designer cells: artificial enzyme can activate a gene switch

22.05.2018 | Life Sciences

PR of MCC: Carbon removal from atmosphere unavoidable for 1.5 degree target

22.05.2018 | Earth Sciences

Achema 2018: New camera system monitors distillation and helps save energy

22.05.2018 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>