How Science Is Helping Save Koalas

Jul 30, 2018 By Anisha C, Writer Intern
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Koalas-- these cuddly, furry, huggable creatures are known for their Australian roots, wonky diet, and impressive nap times. But they have sadly become endangered over the past few decades.

Scientists have long known that the species’ rapid decline has been due to outside causes such as deforestation, and internal causes such as weakness to disease. But now they have a readable map for koala DNA.

Just recently, researchers finished decoding the entirety of the koalas’ genome, all 26,000 genes! This new knowledge will give scientists information about key traits in koalas -- how they eat extremely poisonous leaves, why they are so susceptible to Chlamydia (an easily treatable disease), and how we can help koalas in the future.

Dangers Koalas Face

Humans have been a threat to koalas since the 1800’s, and our impact is still affecting them. According to the Australia Zoo, “in addition to bushfires… dog attacks and road accidents, between 2.5 and 3 million koalas were shot to supply the fur trade in America and Europe from the late 1800s to the early 1900s.”

However, the main problem facing the koala population is something much worse: deforestation. Koalas by nature only feed on a few eucalyptus trees their entire lives. But industrial development and cutting down of trees are causing koalas to lose their homes and their only source of food. The problem is made ten times worse because when a koala’s tree gets bulldozed, they rarely find another tree to feed on and live in. In the end, the koala will just starve to death.

Koalas have a very weak resistance to diseases like Chlamydia and retrovirus. Their bodies are not suited to cope with new (and old) strains, and they have no defense against them.

How Will Mapping Help?

Clearly, mapping the gene is not going to save koalas from deforestation and other human activities that endanger them. However, an understanding of the koala DNA will help scientists detect problems quickly and develop medicines that are more effective. Because of their work on the genome, scientists were able to connect koala's resistance to medicines that treat Chlamydia to their diet of highly poisonous eucalyptus leaves.

A koala’s diet consists solely of the toxin-rich eucalyptus plant. When studying the koala genome, scientists found that their detoxifying genes in koalas were twice as large as that of other animals, including humans. They theorize that somewhere in the koala's evolutionary past, the genes that dealt with toxins must have accidentally replicated, and over time proved beneficial to the species as a whole. Because of these genes, koalas can eat eucalyptus and flush out the poison. Their digestive system is so efficient that most harmful chemicals immediately leave their bodies.

So how does this relate to the deadly chlamydia? Turns out, Chlamydia shouldn’t be deadly. In other animals, chlamydia is not as harmful, and can be treated with medicines and even prevented with vaccinations. But koalas process these treatments differently. Since their bodies are so good at flushing out toxins, the medicines used to treat chlamydia don’t stay in their body long enough to kill the bacteria that cause Chlamydia. Instead, the koala’s body lets the bacteria grow and flushes the medicine pass away.

But there is some good news: with the new map of koala genes, scientists can engineer a koala-specific medicine to combat disease like chlamydia!

Sources: SmithsonianMag, NIH.gov, Australiazoo.com.au, Panda.org, CNN