Koalas are in trouble. One major threat is a virus called KoRV that's linked to cancers and other diseases. KoRV is passed down generationally. But scientists are fighting back with the world's biggest koala family tree. This genetic database could help save the koalas.
The Shrinking Koala Population
Considering the rate at which the population is dying, experts say we could see the extinction of Koalas in the next ten years.
“Since 2018, there has been an estimated 30% decline in Koalas across Australia, with populations estimated to be between 32,065 – 57,920 down from 45,745 – 82,170 in 2018.” – The Australian Koala Foundation.
The North American koala population in zoological gardens was established between 1976 and 1981 with 14 koalas from Australia. More than 40 years later, the San Diego Zoo Wildlife Alliance cares for 30 koalas – the largest colony outside Australia.
“The koalas in this investigation are part of one of the most comprehensive family trees in the world, with familial relationships reliably documented over decades of careful species maintenance and bio-banking”, says David Alquezar, Ph.D., Manager of the Australian Centre for Wildlife Genomics, Australian Museum Research Institute.
Why It Matters:
This extensive family tree, meticulously documented over decades, provides a goldmine of information. Researchers like David Alquezar use this ‘closed system' to explore KoRV mobility and its impact on disease outcomes.
KoRV Transmission – How It Hitches a Ride Through Generations
KoRV is a special kind of virus with vertical retrovirus transmission. This means it can hitch a ride in a koala's sperm or egg.
This “endogenous” KoRV is different from the usual “catch-a-cold” kind that spreads between individuals. Instead, it gets passed down like a family heirloom (yikes!)
Bonus fun fact: Did you know 8% of our own human DNA comes from ancient retroviruses? We're basically walking family trees ourselves!
KoRV's journey is unique in that unlike most species whose retroviral integrations happened millions of years ago, KoRV is a recent player in the genetic game, starting its endogenization just 50,000 years ago. Some of its subtypes still pose a threat, causing health issues in koalas living both in the wild and in human care.
Unique Challenges of Fighting KoRV
Koalas face a unique set of challenges, with KoRV making them more susceptible to bacterial infections, leukemia, and cancer. The research team, led by the San Diego Zoo Wildlife Alliance, took on the challenge. They looked into five generations of koalas at the San Diego Zoo, to better understand KoRV integration into their genomes.
If we think of koalas as a big, interconnected family, then understanding their family tree and genetic makeup helps researchers identify key players in the transmission game, making it a bit like solving a wildlife mystery.
Protecting Koalas From Cancer's Grasp
All koalas carry a high risk of cancer. Cora Singleton, head veterinarian at the San Diego Zoo Wildlife Alliance, sheds light on the challenge of detecting early-stage cancer in these fluffy creatures.
“Koalas are very good at hiding the early stages of some cancers. They can appear normal one day and suddenly show a subtle change in behavior the next. We examine their blood and bone marrow and then realize they have late-stage cancer, which progresses rapidly.” There is currently no adequate treatment for the affected koalas.
The Koala Genome Project – Decoding Nature's Blueprint
A global team of wildlife heroes, including the San Diego Zoo Wildlife Alliance, Illumina, the University of Sydney, and more, are joining forces to create the Koala Genome Project. This project aims to tackle these threats head-on and secure the long-term survival of Koalas.
Why is this a big deal? Knowing how KoRV jumps generations could help us:
- Breed healthier koalas: By understanding which KoRV variations are harmful, we can breed koalas that are less likely to inherit cancer-causing viruses.
- Save wild koalas: This research could help us protect koalas in the wild too, who face threats like habitat loss and climate change on top of KoRV.
But there's a twist: KoRV isn't all bad. In some cases, viruses like KoRV can actually be beneficial, introducing new genetic diversity. The scientists are still figuring out this dance between virus and host and how long it takes for them to settle into a comfortable routine.
Defying the KoRV Threat
As of now, there's no magic cure for affected koalas. The urgency lies in disease prevention through testing and breeding programs.
“Whether we can reduce the impact of KoRV-induced diseases on koala populations through testing and breeding programs is a crucial question for the health and welfare of the animals,” says Dr. Rachael Tarlinton from the University of Nottingham's School of Veterinary Medicine and Science.
Resources to find out more info: