Polar bear study may boost fight against obesity

Thursday 08 May 2014 22.48
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Polar bears have a diet very high in fat
Polar bears have a diet very high in fat
The team found that polar bears have existed for around 400,000-600,000 years
The team found that polar bears have existed for around 400,000-600,000 years

An international study involving scientists in Ireland has found the genetic make-up of polar bears could help provide solutions to the global problem of obesity in humans.

The research, the most comprehensive genomic study of polar bears ever undertaken, also revealed that the species is considerably younger than previously thought.

The research began with a team of scientists from Denmark taking samples from 79 polar bears in Greenland, northern Russia and Alaska and a further ten brown bears.

The samples were then used by scientists at the Beijing Genomics Institute in China to produce the genomes or genetic code of the bears.

That data was then analysed by researchers in California, NUI Maynooth and Dublin City University, who have an interest in the genetics of animals and organisms that live in extreme environments.

The results are published in the current edition of the leading international journal Cell.

The team found that polar bears have existed for around 400,000-600,000 years, much less than the four million years previously thought.

The research points to polar bears diverging from brown bears at a time when ice covered far more of the planet than it does today.

The team also found evidence of the genetic divergence that led to polar bears having white fur - a necessity for them to be able to hunt in an ice and snow-covered environment.

The scientists were particularly interested in understanding how it was that polar bears could eat such a fat-laden diet, without suffering from cardiovascular problems like humans do.

Polar bears live on blubber and 50% of their bodies are made up of fat.

Their analysis found mutations in genes involved in fat metabolism that make them look radically different from similar genes in other species.

The team concluded the variants had evolved to better equip the polar bears for Arctic life.

One consequence of their findings is that it could help scientists and doctors better understand how humans could manage fat levels in their bodies.

According to Professor James McInerney, co-director of the Bioinformatics and Molecular Evolution Unit at NUI Maynooth, if we can understand how polar bears stay healthy and protected from heart disease, despite such a high fat and cholesterol diet, we could get insights into developing protection in a human system.

Dr Mary O'Connell, principal investigator at the Department of Biotechnology at Dublin City University, said such in-depth analysis of the genomes of different extreme species could in future help us to answer questions about many topics, including diseases, longevity and ageing.

This is because the genetic make-up of different organisms can be compared to one another, to see what makes them look and behave differently.

The research will also assist in the overall understanding of the popular species in the face of the growing threat of climate change.

There are currently around 25,000 polar bears left, and the species is considered vulnerable to possible extinction in the future.