Polar bear evolution key to heart disease treatment
Published 09/05/2014 | 02:30
RESEARCH by Irish scientists into polar bears could help medics treat heart disease.
The team looked at the bears' diet – plenty of fat and not drinking fresh water – and how it doesn't affect their bodies.
"If you think about having a diet which is entirely animal fat-based, you'd be pretty sick. Polar bears have mastered the art," said DCU's Dr Mary O'Connell.
"They live on mostly ring seals, and eat the blubber. In many cases they only eat the blubber, their entire existence is based around fat. In terms of their body mass, up to 50pc can be fat.
"The other cool thing they do is if you're metabolizing the fat, the side product is water. Polar bears don't drink water. If you think about it, where would they get fresh water anyway? So they don't drink."
The team have also helped discover that the polar bear is far younger than previously believed. In evolutionary terms, it's only a baby.
The researchers have learned that the Arctic bear is between 343,000 and 479,000 years old, far less than the five million years previously believed. They evolved from a group of brown bears which became isolated in the far north and were forced to adapt to sub-zero conditions.
Instead of adapting over millions of years, the ancient group of stranded brown bears adapted to cope with temperatures as low as minus 40C and developed an ability to survive on blubber in just 20,000 generations – a "blink of an eye".
"In terms of evolutionary biology, this is yesterday," Dr Mary O'Connell said. "Most people believe evolution involves slow changes over time. This study has shaped up our thinking on evolution.
"It's an incredibly fast adaptation. I think this is the first time we have seen this happen so quickly in such a big animal."
Scientists used DNA samples from 79 polar bears and 10 brown bears to complete the study, in which the gene sequence of the animals were mapped using hair, blood and tissue samples.
While the number of stranded brown bears which gave rise to the polar bear is not known, it would have to be large enough to support a population. Dr O'Connell said just 25,000 polar bears are believed to survive in the wild at the moment.