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The populations of these marsupials are expected to decrease by 50% throughout Australia over the next three generations
Agencia SINC • 12 July 2018
The koala (Phascolarctos cinereus) is an emblematic species of L & Australia recognized worldwide. Because of its unique biological character, it is of interest to scientists, governments and the public alike. However, there are fewer and fewer
According to experts, koala populations are expected to decrease by 50% in Australia over the next three generations (about 20 years).
Koalas are unique pieces in the history of evolution. They are the only living representatives of the marsupial family of fascolárctidos. They can eat poisonous eucalyptus leaves that would kill most mammals. The threats of predation and the loss of habitat due to urbanization make them particularly vulnerable. They are threatened by diseases, low genetic diversity and climate change.
A team of scientists, led by the Research Institute of the Australian Museum and the University of Sydney, sequenced the koala genome using advanced technology. reading and optical mapping. "The genome provides a springboard for the conservation of this biologically unique species," says Katherine Belov, co-author of the University of Sydney and professor of comparative genomics.
The work revealed an expansion of gene families linked to detoxifying enzymes, which allow koalas to feed on eucalyptus leaves rich in phenolic compounds.
These genes have been expressed in many koala tissues, particularly in the liver, indicating that they play a very important role in detoxification. It is likely that koalas have become specialists in the koala. ;food. As Rebecca Johnson, director of the Australian Museum's Research Institute, explains, "this allowed them to find their subsistence niche to survive since they could count on a less competitive food source for them." other species that could not detoxify as effectively.
In addition, they identified groups of genes related to the immune system that will improve the study of Chlamydia infection, common among koalas populations. "The Koala Genome Consortium has been an ambitious journey that gives us a good understanding of the genetic components that make up this animal, one of the most charismatic and iconic mammals in Australia and around the world," says Johnson. conserve the species
The consortium is led by Australian scientists and seven other countries and has 29 institutions. They sequenced a total of more than 3,400 million base pairs and more than 26,000 genomes of the koala genome.
Australia has the highest extinction rate of mammals compared to any country in the world during the Anthropocene. The number of koalas has dropped in the north since European colonization, but has increased in some parts of the south, particularly in Victoria and southern Australia. The uneven response of koala populations throughout their range is one of the greatest challenges of large scale management of the species.
The genome was sequenced at the Ramaciotti Center for Genomics of the University. of New South Wales, using a new sequencing technology. "Then we badembled the genome with supercomputers, which allowed the Consortium to study the more than 20,000 genes of this unique species," says Marc Wilkins, director of the Ramaciotti Center
Secrets of milk [19659010] of the composition of koala milk. Like all marsupials, koalas spend most of their development in a bag. They are born without an immune system between 34 and 36 days of gestation and spend about six months developing in the bag.
"We characterize the major components of bad milk, which is crucial for koala newborns, who are born sized to a bean and weigh half a gram," says Belov. "We identify the genes that allow the koala to adjust the composition of the milk protein throughout the stages of lactation, to meet the changing needs of their offspring. "
Chlamydia and retroviruses attack koalas
The koalas of New South Wales and Queensland have been affected by chlamydia, a disease that causes them infertility and blindness.By using the information obtained from the koala genome, scientists hope to develop a vaccine to fight this disease and other diseases.
In addition to chlamydia, koala retrovirus (KoRV) is another major infection that threatens the koala, very little about it. "The complete genome is fundamental to show how a only koala can have more than a hundred KoRV inserts in its genome, including many versions of KoRV, "says Professor Peter Timms of the Sunshine Coast University. "This information will allow us to determine which strains of KoRV are the most dangerous and help in the development of a vaccine against KoRV"
All sequencing data generated by the Koala Genome Consortium was filed in public databases and they were made available free of charge to scientists around the world. "Open information maximizes the benefits that koala populations and the public derive from research," says Johnson
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