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:2/11/2016)... , ... February 12, 2016 , ... Fitbody Personal Training ... a fun and exciting way to get fit and healthy. Located in Phoenixville, PA, ... dates for a class designed for horseback riders who want to lose weight and ...
(Date:2/11/2016)... (PRWEB) , ... February 11, 2016 , ... ... participated in the American Osteopathic Association’s (AOA) Match Program Tuesday, February 9, taking ... Program places students into osteopathic graduate medical education positions across the country. Of ...
(Date:2/11/2016)... ... February 12, 2016 , ... The Journal of Pain Research ... in 2013. The SJR uses data taken from the Scopus database (Elsevier B.V.) and ... of citations received by the journal over a three year period and also the ...
(Date:2/11/2016)... ... 2016 , ... Hall Integrative Health and Chiropractic, PC which ... grand openings in March. All seven practices are set to start accepting patients ... diabetes possible? According to this 2011 CNN article it is possible: http://www.cnn.com/2011/HEALTH/01/28/reverse.diabetes/ ...
(Date:2/11/2016)... (PRWEB) , ... February 11, 2016 , ... ... upcoming Feb. 23 webinar, “Intel’s Direct-to-Employee Benefit Model: A Case Study for Plans ... Catholic health care system that’s partnering with Intel on value-based health benefits program ...
Breaking Medicine News(10 mins):
(Date:2/12/2016)... Ky. , Feb. 12, 2016 /PRNewswire/ ... has completed a $47.1 million Series D ... Cormorant Asset Management, Hillhouse Capital Group and ... Morningside Venture Investments, AJU IB Investment, and ... be used to further advance clinical trials ...
(Date:2/11/2016)... , Feb. 11, 2016 Stem cells are ... characterized by self-renewal and the capacity to differentiate into ... new discovery, as the first mouse embryonic stem cells ... not until 1995 that the first culturing of embryonic ... cells were not produced until 2006 As a result ...
(Date:2/11/2016)... 11, 2016  Governor Andrew M. Cuomo today announced ... jobs throughout Western New York . ... SUNY Polytechnic Institute, includes a major expansion of Athenex,s ... Buffalo , as well as the creation ... Dunkirk . The combined projects are ...
Breaking Medicine Technology: