Climate change makes more shrew species, 70 genetic varieties

Oct 23, 2012

Anyone who went outside this summer felt the effects of climate change. Now the Eurasian shrew, Sorex araneus, can say the same. A new study by P. David Polly of Indiana University found that climate change caused shrews to change, genetically, and eventually become different species. Using shrew DNA and fossils, he found that this change occurred over hundreds of thousands of years during repeated times of extreme cold, or glaciations.

Over the last 740,000 years the Earth has gone through eight different glaciation events, with warmer times between them when the ice sheets subsided, called interglacial events – we are currently in one of these now. In Europe and Asia these substantial glaciers diminished the home ranges of the tiny shrews that live there and forced them to congregate in smaller areas called glacial refugia (little refuges from the cold). Polly found that during glacial periods Eurasian shrews went to one of 10 refugia; these refugia served as a means to keep each group of shrews separate from other groups, allowing each group to develop their own distinct genetic signal. When the ice subsided, the shrews all came together again and had little difficulty inbreeding, but they still kept a genetic signal from their refugium. The Eurasian has gone through this cycle multiple times, corresponding to multiple glaciations events, eventually leading to 70 different genetic varieties!

Since the were more protracted than the interglacial periods, the shrews were in the refugia longer than they were intermixing. The long-term isolation in the refugia has built up enough genetic differentiation to consider some of these varieties separate species. "The have an important effect on and genetic differentiation, but it isn't speciation every cycle, but rather two steps forward and one step back," said Polly. Not only does Sorex araneus fit this pattern, its more and other small critters seem to fit it too. Polly commented, "The populations that are most easily and completely isolated have speciated, whereas the ones that are isolated in glacial refugia only transiently have lots of diversity, but they haven't speciated." Will future climate change make more shrew species, or fewer? Only time and science can tell.

Explore further: New technique improves forecasts for Canada's prized salmon fishery

Related Stories

The difference between a mole and shrew is in their SOX

Aug 08, 2012

The family of small insectivores, Talpidae, includes the moles, shrew moles, and aquatic desmans. New research published in BioMed Central's open access journal EvoDevo has found that the enlargement of mol ...

How water shrews find prey in the dark

Feb 07, 2008

Shrews are tiny mammals that have been widely characterized as simple and primitive. This traditional view is challenged by a new study of the hunting methods of an aquatic member of the species, the water ...

Recommended for you

World's wildlife critical to the economies of nations

15 hours ago

Wildlife is critical to the economies of nations. New Zealand's wildlife – whales, dolphins, red deer, thar, albatross, kiwi, tuatara, fish and kauri – attract tourists. And the tourists who come to see ...

Modern methods lead the way toward a rhino rebound

15 hours ago

Cutting-edge technology and techniques have become essential tools in the effort to save rhinos. Micro chips, translocation and consumer campaigns are helping shift the balance against record-setting poaching ...

The water trading strategies of plants

16 hours ago

Plants trade water for carbon – every litre of water that they extract from the soil allows them to take up a few more grams of carbon from the atmosphere to use in growth. A new global study, led by Australian ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.