Navigation Links
Female Ancestor of All Living Polar Bears Was Brown
Date:7/7/2011

THURSDAY, July 7 (HealthDay News) -- The female ancestor of all living polar bears was a brown bear that lived in the vicinity of present-day Britain and Ireland 20,000 to 50,000 years ago, according to an international team of scientists.

It's likely that climate changes that affected the North Atlantic ice sheet led to periodic overlaps in bear habitats and interbreeding between brown bears and polar bears. This resulted in maternal DNA from brown bears being introduced into polar bears, explained team co-leader Beth Shapiro, an associate professor of biology at Penn State University.

Previous research suggested that the ancient female ancestor of modern polar bears lived on three Alaskan islands (Admiralty, Baranof, and Chichagof) only 14,000 years ago.

Polar bears and brown bears such as Grizzlies and Kodiaks are markedly different species in terms of behavior and physical features such as body size, skin and coat color, fur type, tooth structure.

"Despite these differences, we know that the two species have interbred opportunistically and probably on many occasions during the last 100,000 years," Shapiro said in a Penn State news release. "Most importantly, previous research has indicated that the brown bear contributed genetic material to the polar bear's mitochondrial lineage -- the maternal part of the genome, or the DNA that is passed exclusively from mothers to offspring. But, until now, it was unclear just when modern polar bears acquired their mitochondrial genome in its present form."

For this study, Shapiro and her colleagues analyzed 242 brown bear and polar bear mitochondrial lineages from a number of regions. The specific population of brown bears that contributed maternal DNA to modern polar bears has been extinct for about 9,000 years, but there's clear genetic evidence that these brown bears and polar bears were in contact long before brown bears vanished from the British Isles.

Learning more about the polar bear's genetic history and its response to previous environmental changes may help guide efforts to conserve the dwindling population of polar bears, Shapiro said.

The study was published July 7 in the journal Current Biology.

More information

Polar Bears International has more about polar bears.

-- Robert Preidt

SOURCE: Penn State University, news release, July 7, 2011


'/>"/>
Copyright©2010 ScoutNews,LLC.
All rights reserved  

Related medicine news :

1. Female mate choice enhances offspring fitness in an annual herb
2. Has Chinas campaign against female feticide done more harm than good?
3. Undernourishment in pregnant, lactating females found key to next generations disease
4. Supplement found to improve quality of life for female cancer survivors
5. Young females are victims of violent injury
6. Research study reveals profile for female drunk-drivers
7. Gene Variation May Explain Some Female Infertility Cases
8. How materialistic advertising messages negatively shape the female body image
9. UNC study finds oral tongue cancer increasing in young, white females
10. Study: Facebook photo sharing reflects focus on female appearance
11. New educational DVD improves female pelvic exam instruction
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Female Ancestor of All Living Polar Bears Was Brown
(Date:12/9/2016)... Harrisburg, PA (PRWEB) , ... December 09, 2016 ... ... concussion education program through the Pennsylvania Cable Network (PCN) during the summer of ... Brain Injury Implementation Grant provided by the United States Department of Health and ...
(Date:12/8/2016)... Pennsylvania (PRWEB) , ... December 08, 2016 , ... ... Duck Donuts Franchising Company LLC, announced the first national #QuackGivesBack campaign which ... , “This was our first franchise-wide Quack Gives Back initiative, ...
(Date:12/8/2016)... , ... December 08, 2016 , ... CURE Media Group, ... and advocacy groups, has aligned with Upstage Lung Cancer in efforts to combat lung ... announcement, Michael J. Hennessy, Jr said, “CURE Media Group is honored to team up ...
(Date:12/8/2016)... ... December 08, 2016 , ... SunView Software aims ... employees that are both engaging and easy to use. Coming off the heels ... company revealed today its plans to roll out new AI-powered self-service enhancements to ...
(Date:12/8/2016)... Dallas, TX (PRWEB) , ... December 08, 2016 , ... ... to continue to be a convenient service for Texas, they are expanding their presence ... will involve a hiring spree that will bring new jobs to the Dallas and ...
Breaking Medicine News(10 mins):
(Date:12/9/2016)... 2016 Research and Markets has announced ... report to their offering. ... The report forecasts the global optical transceiver market to ... The report covers the present scenario and the growth ... the market size, the report considers the revenue generated from the ...
(Date:12/9/2016)... Pharma, Inc. (Nasdaq: LIFE ), a biotherapeutics company engaged ... rare diseases, today announced that senior management will participate in a ... at the InterContinental Barclay Hotel in New York City ... About aTyr Pharma ... aTyr Pharma is engaged in the discovery ...
(Date:12/9/2016)... 2016  Axovant Sciences Ltd. (NYSE: ... on the treatment of dementia, today announced a ... 2b trial evaluating treatment with intepirdine (RVT-101), combined ... plus placebo in people with mild-to-moderate Alzheimer,s disease. ... to treatment was associated with reduced progression in ...
Breaking Medicine Technology: