They’re soft, cute and cuddly.
Researchers hope marsupials’ survival in its genetic code
But koalas also are threatened. Can their genome help humans save them?
The koala is an unusual creature. Native to Australia and a bit bigger than a raccoon, it spends most of its time in eucalyptus trees, gorging on leaves that are toxic to nearly every other animal on the planet.
The koala sleeps about 22 hours a day and spends the remainder of its time eating and resting. It might spend 10 minutes a day moving, experts say, usually from one tree to another.
The unique lifestyle of the koala has helped it thrive for 350,000 years, but today the cute and iconic creature is facing threats from habitat loss, disease and a changing climate.
Koala populations are expected to decline by 50 percent in the next 20 years, according to the Australian Museum.
To help protect these animals, which bring in an estimated $1.1 billion to Australia each year through koala-related tourism, an international team of researchers has published the first complete genome of the koala.
Their hope is that the keys to the marsupials’ longterm survival might be embedded in its genetic code.
The koala genome has 26,000 genes, which makes it slightly larger than the human genome.
A preliminary analysis of the koala’s genome, published this month in Nature Genetics, has already yielded some intriguing findings.
The authors found that compared to other mammals, the koala’s DNA includes an expansion in the number of genes that encode for enzymes involved in detoxification. That allows them to have a diet that depends almost entirely of eucalyptus leaves, which are unusually high in toxins.
The koala genome also revealed why koalas are such notoriously picky eaters. They are known to consume leaves from just 20 of Australia’s 600 known eucalyptus species. Even when they are in one of their preferred trees, koalas take leaf selection seriously, often picking only one or two from a bunch to eat.
This behavior can be explained by an expansion in the number of genes involved in their ability to discern a bitter taste and their nasal receptors, she said.
The research team thinks the bitter genes allow the koalas to pick leaves with the least amount of toxins, while the nasal receptor expansion might help them sniff out which leaves have a higher water content. Since koalas get most of their water from their diet of leaves, this would be a useful adaptation.