They manage to sequence the genome of the koala

Paris. – The koala, Australia's iconic marsupial, has just revealed the secret of its genome, a breakthrough that could help protect this vulnerable animal whose population is so dramatically reduced "Koalas are threatened in Australia, and the genome sequence has helped us to document and understand their genetic diversity and will be useful for future conservation work, "Rebecca Johnson of the Sydney Australian Museum, co-author of the Australian Museum, told AFP. ;study. study

Koalas are found in the forests of east and southeast of Australia, as well as on 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 today, which means that this marsupial appears as "vulnerable" on the International Union's red list for nature conservation (IUCN).

"Excellent toolkit"

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.

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 to find a niche (food) to survive, and it can rely on this virtually uncompetitive food source, since other species can not detoxify as efficiently," says Rebecca Johnson. .

But this peculiarity 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 because of the intensification of deforestation and the Urban development.

Vaccinate the Koalas

Researchers also identified genes related 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.

In addition, human development invades the territory of koalas, which forces them to live closer and closer to each other, which 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 among the koalas of Victoria and southern Australia than among his cousins ​​in Queensland and New South Wales.

The decryption of the DNA of these populations "allows us to make recommendations to preserve diversity", where it exists, and "plan trips to improve," concludes the researcher, the case applicable.