Koala’s Genetic Diversity Suggests Decline Caused By Humans

Unlike other marsupials, koalas are not in bred, suggesting that other factors are responsible for their decline.

AsianScientist (Nov. 26, 2015) – The koala genome has been studied across the species range for the first time, revealing revealed that koalas (Phascolarctos cinereus) are genetically diverse. The study, published in Conservation Genetics, indicates that declining populations are the result of human-related activity rather than mating with kin.

Previous research has shown many marsupials have low genetic diversity, which is often a sign of inbreeding and mating with kin and is not unusual in animals with declining populations.

It has long been thought that low levels of koala genetic diversity are a reason for their declining populations and local extinctions but researchers from the University of Sydney and James Cook University have found this is not the case.

Professor Herman Raadsma from the University of Sydney’s Faculty of Veterinary Science said contrary to popular opinion, the research showed koalas were as diverse as many other wild species.

“These results show the genetic diversity of the koalas on the east coast of Australia is far from being inbred,” said Raadsma.

This new study, conducted in partnership with San Diego Zoo and the non-government organisation, Science for Wildlife, used cutting-edge genetic technology to answer critical questions about koala conservation. The group applied whole-genome DNA sequencing to show that koalas still maintain higher levels of genetic diversity than originally thought.

James Cook University’s Associate Professor Kyall Zenger said the finding was exciting, given that koala numbers had been declining to the point where they were listed at risk of becoming endangered.

“To effectively manage koalas across Australia and in captivity we must understand how genetically diverse these populations are–how ‘fit’ they are,” Zenger said.

Ms. Shannon Kjeldsen, a PhD student working on the project at James Cook University, said her research also showed that although koalas varied greatly in appearance in southern and northern Australia, there was very little evidence that there were different species, bringing into question the current recognition of the existence of three distinct sub-species.

“We know that it would be unwise to move koalas between these regions because they live in different climates and have adapted to different environments, but we do not know where the management boundaries lie,” Kjeldsen said.

Zenger said management and implementation of a national koala conservation program was vitally important to protect this charismatic species.

“Until now there has been a lack of species-wide information to help coordinate conservation efforts,” Zenger said.

The tool should also enable better management of captive breeding populations.

The article can be found at: Kjeldsen et al. (2015) Genome-wide SNP Loci Reveal Novel Insights into Koala (Phascolarctos Cinereus) Population Variability Across its Range.


Source: The University of Sydney.
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