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"Koalas are threatened in Australia, and the genome sequence has helped us document and understand their genetic diversity and will be useful for future conservation work," said Rebecca Johnson, of the Australian Museum of Medicine. Sydney. study
Koalas are found in the forests of eastern and southeastern Australia, as well as in some islands of the "continent". But the Australian icon, which some do not hesitate to call "national treasure", is the victim of the destruction of its habitat, climate change, unscrupulous drivers, dogs, and so on.
When the first British settlers arrived in 1788, koalas were more than ten million. But according to the Australian Koala Foundation, there are just over 43,000 in nature today, which means that this marsupial is listed as "vulnerable" on the Red List. International Union for the Conservation of Nature (IUCN). 19659002] "Excellent Toolbox"
More than 50 researchers from seven countries collaborated on this study published this Monday in the journal Nature Genetics. They discovered 26,558 genes, deciphering the marsupial genome "with an accuracy of 95.1%, which is comparable to what has been achieved with the human genome."
An advance that allows to know a little more about the unique biology of this animal, endemic in Australia. Especially on "the excellent toolbox", a particular assemblage of genes, which allows it to digest (the leaves of) eucalyptus, which contains phenols (phenolic or phenyl, among other names) toxic for other animals. [19659002] The koala easily devours a kilogram of eucalyptus leaves a day (although he sleeps 20 hours a day by digesting them).
"This has probably helped you find a niche (food) to survive. You can count on this food source almost without competition, since other species can not detoxify as effectively," says Rebecca Johnson
But this trait that can be considered as an advantage has its counterpart: this almost exclusive regime makes it particularly vulnerable to the disappearance of eucalyptus forests, either through the intensification of deforestation and the development
Vaccinating koalas
Researchers have also identified the genes linked to their immune system: a step towards the development of vaccines to fight against certain diseases, such as chlamydia (asymptomatic bacterial infection) which devastates koala populations.There is currently no treatment for this sexually transmitted disease, which can lead to blindness, infertility and death
Moreover, human development invades the territory of koalas, forcing them to live closer and closer to each other. this increases the interaction between individuals and the risk of contamination.
According to the researchers, koalas isolated by the fragmentation of their habitat become poorer at the genetic level, which can favor problems of consanguinity. According to Johnson, the latter is higher in the koalas of Victoria and southern Australia than among his cousins in Queensland and New South Wales.
The deciphering of the DNA of these populations "allows us to make recommendations to preserve the diversity", when it exists, and "to envisage displacements to improve it", concludes the researcher, if necessary
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