. Earth Science News .

Polar bears older than previously thought: study
by Staff Writers
Washington (AFP) April 19, 2012

Polar bears diverged from their closest relatives 600,000 years ago, far earlier than previously thought, suggesting more challenges in the face of climate change, scientists said Thursday.

Previous genetic analysis of polar bears had determined the species was only about 150,000 years old. But in fact, it took them five times longer for the polar bear to adapt to arctic conditions, according to the study by Frank Hailer and colleagues.

In turn, the bears may not have enough time to adjust to a rapidly changing climate, the study suggested.

The earlier studies had focused mainly on mitochondrial or mtDNA, which only accounts for a small portion of the entire genome and is passed from a mother to her offspring. They had concluded that polar bears were a recently evolved type of northern brown bear.

But Hailer's study, published in Friday's edition of the journal Science, examined data from many independently inherited regions of the nuclear genome that showed that both polar and brown bears are much older, genetically distinct species of their own right.

The species' earlier origin "implies that polar bears as a species have experienced multiple glacial cycles and had considerable time to adapt to arctic conditions," the study said.

"However, the low genetic diversity in polar bears suggests that changes in the environment, such as warm phases, caused population bottlenecks."

It warned that changes in habitat, hunting, toxic substances and other "stressors" caused by humans "could magnify the impact of current climate change, posing a novel and likely profound threat to polar bear survival."

Related Links
Beyond the Ice Age

Get Our Free Newsletters Via Email
Buy Advertising Editorial Enquiries


. Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Wen to promote China's Arctic ambition in Europe
Beijing (AFP) April 19, 2012
The Arctic and its vast energy reserves, one of the last places on earth where sovereignty has not been established, will be a key focus of Chinese Premier Wen Jiabao's trip to Europe. Wen leaves Friday for an eight-day trip that will take him to Iceland, Sweden, Poland and Germany, and will touch on China's Arctic ambitions as well as the ongoing eurozone debt crisis. Iceland's strateg ... read more

Desolation of Pakistan avalanche site

Lawyer to take over at Fukushima plant operator

Toxic gases hamper search at Pakistan avalanche site

New underwater images show damage at Fukushima

US judge allows tech 'poaching' suit to proceed

Hollywood studios lose landmark download case

Raytheon's Space Fence System Detects and Tracks Space Objects

Greenpeace says cloud computing 'dirty'

Africa said rich in underground water

Three Gorges Dam prompts more evacuations

New purple crab species found in Philippines

Coral Reef Winners and Losers in a Warmer World

Polar bears older than previously thought: study

Chinese PM wraps up Iceland visit

Wen to promote China's Arctic ambition in Europe

CU-Boulder study shows Greenland may be slip-sliding away due to surface lake melt

That is why plants grow towards the light

Southeast Asia's billion dollar cassava industry at high risk due to climate change

Nutrient and toxin all at once: How plants absorb the perfect quantity of minerals

Scientists discover 'switch' in plants to create flowers

New research puts focus on earthquake, tsunami hazard for southern California

Mexico volcano roars, spews glowing rocks

Ancient Greek tsunami bears warning signs: study

Tokyo mega-quake would kill over 9,000: simulation

G.Bissau will 'defend itself' if foreign troops sent: junta

Diarra: launch of NASA scientist into Mali politics

G.Bissau army says coup bid over secret deal with Angola

ECOWAS council asks regional leaders to okay Mali force

Chimpanzee ground nests offer new insight into our ancestors descent from the trees

Genetic adaptation of fat metabolism key to development of human brain

Majority-biased learning

Development of the glial cell revealed

Memory Foam Mattress Review

Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News


The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement