The koala is one of the most fascinating and iconic mammals in the world. This animal is not only synonymous with Australia, but also a powerful international symbol for the conservation of our natural world. Now, an international team of scientists (54 scientists and 29 institutions from different countries) have succeeded in sequencing the koala genome: 3.4 billion base pairs and more than 26,000 genes.
Because it is important? This endearing animal attracts millions of tourists every year, but the number of koalas in the wild is decreasing, hence the experts got down to work to unravel its genome in search of clues on how to save them, since some populations of koalas are less genetically diverse than others.
Unlocking the genomic sequence gives scientists an unprecedented insight into the unique biology of the koala.
“The Koala Genome Consortium has been an ambitious journey that gives us great insight into the genetic components that make up a koala, one of Australia’s most iconic and charismatic mammals ,” explains Rebecca Johnson, Director of the Australian Museum Research Institute.
“The genome provides a springboard for the conservation of this biologically unique species”, clarifies Katherine Belov, co-author of the study published in the journal Nature .
Their number is decreasing
Koalas face a number of threats to their survival. In addition to the loss of their natural habitat since the arrival of Europeans, which severely reduces their genetic diversity, koalas face the daily danger of being run over by vehicles or attacked by dogs, even in areas where they thrive.
Additionally, chlamydia is a persistent threat that causes blindness and infertility; koalas also suffer from the koala retrovirus (KoRV).
The research has also allowed scientists to explore many of the interesting qualities of koalas, including how they manage to survive on a rather peculiar diet of eucalyptus leaves (which contain substances that would be lethal to other animals). “The koala has developed an excellent set of tools to deal with the consumption of highly toxic eucalyptus leaves,” says Will Nash of the Earlham Institute.
The experts discovered that certain genes related to the ability to eliminate toxins were expressed in many koala tissues, particularly in the liver ; which indicates that they have a very important function in detoxification. “This probably helped them find their place to survive, as they could count on a food source that would have less competition with other species that could not detoxify as effectively,” says Johnson.
The counterpoint is that, despite the fact that creating this food niche helped them to prosper, it has also made them vulnerable , since now they have no other home than the eucalyptus forests, hence the International Union for Conservation of Nature ( IUCN) has included them as vulnerable species due to the expansion of cities and the extension of crops.
“The completion of the koala genome is a milestone for the study of the evolution of mammalian genomes and for the conservation of this emblematic but threatened species,” concludes Wilfried Haerty, an expert in Evolutionary Genomics, who also participated in the study.
Reference: Rebecca N. Johnson et al. “Adaptation and conservation insights from the koala genome” Nature Genetics 2018 DOI: DOI: 10.1038 / s41588-018-0153-5