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.

Lea
'/>"/>

Copyright©2010 ScoutNews,LLC.
All rights reserved  

Page: 1 2

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:7/9/2014)... feelings are personal and subjective, the human brain ... represents emotions across different senses, situations and even ... neuroscientist Adam Anderson. , "We discovered that fine-grained ... an area of the brain associated with emotional ... an individual,s subjective feeling," says Anderson, associate professor ...
(Date:7/9/2014)... There has been a sharp increase in the ... using MyChart, the online, interactive service that allows patients ... healthcare providers, schedule appointments, and renew prescriptions. , Over ... MyChart each year increased five-fold, while the ... 10-fold, according to a study by Dr. David ...
(Date:7/9/2014)... declines and extinctions around the world have been ... but new research from the National Institute for ... pathogen, ranavirus, may also contribute. , In ... ranavirus, which causes severe hemorrhage of internal organs ... of wood frogs if they are exposed to ...
(Date:7/9/2014)... flatulence and have a reputation for being highly toxic, but ... now being being found to offer potential health benefits in ... and dementia. A new compound (AP39), designed and made at ... therapies, by targeting delivery of very small amounts of the ... , Scientists in Exeter have already found that the compound ...
(Date:7/9/2014)... the most important organs in the human body. Its ... properly this is its synthesis function and ... this is its detoxification function. Lack of exercise and ... the liver. The resulting diseased cells can lead to ... failure. According to the German Liver Foundation, over five ...
Breaking Medicine News(10 mins):Health News:Study cracks how the brain processes emotions 2Health News:MyChart use skyrocketing among cancer patients, UT Southwestern study finds 2Health News:MyChart use skyrocketing among cancer patients, UT Southwestern study finds 3Health News:Study predicts ranavirus as potential new culprit in amphibian extinctions 2Health News:Rotten egg gas holds key to healthcare therapies 2Health News:Telemedicine for patients with chronic liver diseases 2Health News:Telemedicine for patients with chronic liver diseases 3
... designs a telemedicine system using interactive digital television. ... of Navarre, Alejandro Fanjul Fernández, has designed a ... This system enables the monitoring and treatment of ... from the comfort and convenience of their homes, ...
... a novel pathway by which estradiol, the primary estrogen ... as it aids in avoiding osteoporosis. // ,It ... bone, and that when the production of estrogen is ... after exposure to radiation or chemotherapeutic drugs, bones become ...
... day give their children a weekly treatment with a nasal ... severe middle //ear infection, based on results of a study. ... use of antibiotics, thereby avoiding the problem of antibiotic resistance. ... is an inflammation of the middle ear space that can ...
... Wisconsin is running a pioneering trial of using stem ... which have //been "encouraging". ,Amish Raval, of ... cardiologists began their trial on March 7. ... it could revolutionize cardiology," said Raval. ,Stem ...
... registered in the US National Marrow Donor Registry// is so ... queue for matching donors. ,Urmi and Girish are ... here. ,Urmi, 5, has been diagnosed with aplastic ... play with her dolls and read stories about Lord Krishna ...
... University College of Dentistry has discovered the first conclusive proof ... human hosts. This can even be ... between 100,000 and 200,000 years ago, say the researchers. ... cariology and comprehensive care at NYUCD, discovered that Streptococcus mutans, ...
Cached Medicine News:Health News:Interactive Digital Television to Monitor Health 2Health News:Interactive Digital Television to Monitor Health 3Health News:Estradiol Guards Against Osteoporosis 2Health News:Viral Enzyme Recruited in Fight Against Ear Infection 2Health News:Viral Enzyme Recruited in Fight Against Ear Infection 3Health News:Tooth Decay Bacteria Evolved Along With Man 2
(Date:1/15/2014)... TORONTO , Jan. 15, 2014  According to ... medical technology market intelligence, the United ... occlusion (TEO) device markets will expand moderately through ... fastest-growing segments. In particular, increasing interest in drug-eluting ...
(Date:1/15/2014)...  Valeant Pharmaceuticals International, Inc. (NYSE: VRX ... under the Hart-Scott-Rodino Antitrust Improvements Act of 1976 ("HSR") ... its indirect wholly-owned subsidiary, Sapphire Subsidiary Corp. ("Purchaser"), for ... Solta Medical, Inc. (NASDAQ: SLTM ) ("Solta") ...
(Date:1/15/2014)...  Zafgen, Inc., a leading biopharmaceutical company dedicated to ... today announced initial results from its Phase 2a ... aminopeptidase 2 (MetAP2), in patients with Prader-Willi syndrome ... results showed improvements in body weight, hunger-related behaviors, ...
Breaking Medicine Technology:US and European Transcatheter Embolization and Occlusion Device Market to Surpass $1.6 Billion by 2022 2US and European Transcatheter Embolization and Occlusion Device Market to Surpass $1.6 Billion by 2022 3Valeant Pharmaceuticals Announces Receipt Of Antitrust Clearance For Its Previously Announced Acquisition Of Solta Medical, Inc. 2Valeant Pharmaceuticals Announces Receipt Of Antitrust Clearance For Its Previously Announced Acquisition Of Solta Medical, Inc. 3Zafgen Announces Initial Results from Phase 2a Study of Beloranib in Patients with Prader-Willi Syndrome 2Zafgen Announces Initial Results from Phase 2a Study of Beloranib in Patients with Prader-Willi Syndrome 3Zafgen Announces Initial Results from Phase 2a Study of Beloranib in Patients with Prader-Willi Syndrome 4
Joseph skin hook is a single end-sharp with 2 prong....
Experience great vision, comfort and durability in a quarterly-replacement lens....
A unique lens system featuring Balanced Progressive Technology for optimum vision quality at every distance....
The proven daily wear spherical soft contact lens....
Medicine Products: