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Posts Tagged ‘Pleistocene’


Reporter: Aviva Lev-Ari, PhD, RN

 

 

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Researchers from Germany, Denmark, and the US sequenced a hyper-variable portion of the koala’s mitochondrial genome sequence using DNA from more than a dozen museum samples. The samples, obtained from museums in Australia and beyond, represented koalas that had been collected in different parts of Australia from the late 1800s to the 1980s.

The team found surprisingly similar mitochondrial profiles in the historical koala samples and samples from modern day koalas. And all four of the mitochondrial haplotypes identified in the older museum samples persist in modern koala populations, the researchers said. That hints that relatively low genetic diversity has been present in koalas for at least 120 years — prior to dramatic population declines at the end of the 19th century, which have been attributed to factors such as hunting, habitat loss, and disease.

“The event which reduced the genetic diversity of koalas must have happened a long time ago, perhaps during the late Pleistocene when the larger species of koala, P. stirtoni, became extinct,” Leibniz-Institute for Zoo and Wildlife Research’s Alex Greenwood, the study’s corresponding author, said in a statement.

SOURCE:

Historically low mitochondrial DNA diversity in koalas (Phascolarctos cinereus)

Kyriakos TsangarasMaria C Avila-ArcosYasuko IshidaKristofer M HelgenAlfred L Roca and Alex D Greenwood

BMC Genetics 2012, 13:92   doi:10.1186/1471-2156-13-92

Published: 24 October 2012

Abstract

Background

The koala (Phascolarctos cinereus) is an arboreal marsupial that was historically widespread across eastern Australia until the end of the 19th century when it suffered a steep population decline. Hunting for the fur trade, habitat conversion, and disease contributed to a precipitous reduction in koala population size during the late 1800s and early 1900s. To examine the effects of these reductions in population size on koala genetic diversity, we sequenced part of the hypervariable region of mitochondrial DNA (mtDNA) in koala museum specimens collected in the 19th and 20th centuries, hypothesizing that the historical samples would exhibit greater genetic diversity.

Results

The mtDNA haplotypes present in historical museum samples were identical to haplotypes found in modern koala populations, and no novel haplotypes were detected. Rarefaction analyses suggested that the mtDNA genetic diversity present in the museum samples was similar to that of modern koalas.

Conclusions

Low mtDNA diversity may have been present in koala populations prior to recent population declines. When considering management strategies, low genetic diversity of the mtDNA hypervariable region may not indicate recent inbreeding or founder events but may reflect an older historical pattern for koalas.

SOURCE:http://www.biomedcentral.com/1471-2156/13/92/abstract

http://www.biomedcentral.com/content/pdf/1471-2156-13-92.pdf

Cutest Koala

This cute baby koala was shot in Currumbin Wildlife Sanctuary, QLD, Australia.
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Learn about Koalas:
The Koala (Phascolarctos cinereus) is a thickset arboreal marsupial herbivore native to Australia, and the only extant representative of the family Phascolarctidae.

The Koala is found in coastal regions of eastern and southern Australia, from near Adelaide to the southern part of Cape York Peninsula. Populations also extend for considerable distances inland in regions with enough moisture to support suitable woodlands. The Koalas of South Australia were largely exterminated during the early part of the 20th century, but the state has since been repopulated with Victorian stock. The Koala is not found in Tasmania or Western Australia.

Koala on Wikipedia

Contrary to (un)popular belief: A koala is NOT a bear!

The US Government have declared the koala a threatened species, however the Australian Government has not. A review of the species national conservation status concluded that the koala are not threatened at a national scale, with a population that numbers in the hundreds of thousands

As with most native Australian animals, the Koala cannot legally be kept as a pet in Australia without a permit.
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About this photo

This was my first photo in Flickr Explore! Check this photo’s Explore history.
Highest recorded Explore: 16 on Saturday, March 29, 2008!

It is currently the number one hit if you search for “koala” on Flickr, and the number one google-hit for “cutest koala”. I get a LOT of views for this one, so thanks goes out to each and ever one of you for having a look at it!

It is currently used as one of several illustrative photos on the Wikipedia article on Koalas.

-Added to the Cream of the Crop pool as most interesting.

You can purchase prints of this photo here! Available framed or on canvas.
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View Large On Black

If you like this photo please consider adding it to your favourites. Also check out my photostream, or just my other animal photos. If you want to licence this photo for commercial use, please contact me by e-mail (erik at erikveland com) or flickr-mail. Cheers mates!

 

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