Cheetah

Cheetah genome shows a cat with nine lives

By [173]Michael Casey
Published December 11, 2015
[174]FoxNews.com
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This undated photo provided by the Indianapolis Zoo shows Pounce, a
cheetah who escaped from its exhibit Sunday, Sept. 6, 2015
(Indianapolis Zoo)

This undated photo provided by the Indianapolis Zoo shows Pounce, a
cheetah who escaped from its exhibit Sunday, Sept. 6, 2015
(Indianapolis Zoo)

Cheetahs may be one of nature’s great survivors.

A new study this week found that the world’s fastest cat has managed to
overcome two population bottlenecks over tens of thousands of years
that could have led to its extinction.

By sequencing the cheetah’s genome, an international team writing in
the journal [180]Genome Biology concluded that the first one came
100,000 years ago when Acinonyx jubatus first migrated out of North
American across the Beringian landbridge to Asia and then eventually
south to Africa. This was a time when all the Pleistocene megafauna
went extinct, including sabretooths, mammoths and the woolly rhino.

Related: [181]Genome sequencing in babies to begin as part of study

The second bottleneck came around 10,000-12,000 years ago, further
reducing its numbers and causing a major reduction in the gene pool
that remains today.

“It was an extinction event in North America and a near extinction
among the survivors that already made it to Asia,” Stephen J. O'Brien,
a co-author on the study and a chief scientific officer at the
Theodosius Dobzhansky Center for Genome Bioinformatics at St.
Petersburg State University, told FoxNews.com.

“Both of these represent a dropping of population size to such low
numbers that their genome diversity reflects it,” he said. “It allows
you to say wow, there was an event that probably was a brush with
extinction â€" I mean the tigers had one about 75,000 years ago when
there was an eruption of some volcano in Southeast Asia.”

To understand its evolutionary history, researchers that also included
members of the Beijing Genomics Institute and the Cheetah Conservation
Fund (CCF) sequenced the genome from a male Namibian cheetah named
'Chewbaaka', and six other wild cheetahs from Tanzania and Namibia.

Related: [182]Can world's biggest shark help humans?

What they found was troubling.

The cheetah’s genome was in poor shape, resulting in elevated rates of
juvenile mortality and the extreme abnormalities in sperm development
and increases vulnerability to infectious disease outbreaks. The
variation in the cheetah genome is far below that observed in inbred
dogs and cats, with researchers showing that the cheetah has lost 90-99
percent of the genetic variation typically seen in outbred mammals.

“The cheetahs themselves look as if they were deliberately inbred
because the amount of variation they have overall throughout the entire
genome is really off the scale as far as being lower than anything else
we have ever seen,” O’Brien said. “The cheetah is like the winner of
the lowest variation of a natural population. To get down that low, you
have to drop down to numbers that are so low that you start inbreeding
with close relatives - even though you have an instinctive avoidance of
it - because there is nothing else to breed with it.”

Spurce .... : http://www.foxnews.com/science/2015/12/11/cheetah-genome-shows-cat-with-nine-lives.html
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