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 Warming ponds could accelerate climate change
21.02.2017 | University of Exeter

nachricht An alternative to opioids? Compound from marine snail is potent pain reliever
21.02.2017 | University of Utah

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017 | Earth Sciences

Novel breast tomosynthesis technique reduces screening recall rate

21.02.2017 | Medical Engineering

Use your Voice – and Smart Homes will “LISTEN”

21.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>