NewsAnimalsSome of Sydneys koalas are chlamydia-free, but still at riskIntroducing new koalas to mate with would help reduce inbreeding, but could also bring in the disease Some koalas (Phascolarctos cinereus) living in the Sydney metro area are isolated from other koalas, keeping them chlamydia-free. But the cost is being worryingly inbred.Carolyn HoggBy Jake Buehler1 hour agoSome of Sydneys koalas are facing an uncompromising dilemma.The koalas living in one corner of Australias largest city are perilously inbred, researchers report February 26 in Conservation Genetics. But the solution interbreeding with neighboring koala populations risks introducing the koalas to a deadly sexually transmitted disease.In 2021 and 2022, University of Sydney conservation biologist Carolyn Hogg and her colleagues determined that koalas in the southwestern Sydney metro area had the lowest genetic diversity anywhere in the state of New South Wales. To investigate further,the researchers caught 111 wild koalas (Phascolarctos cinereus) from seven sites across the forested region south of Sydney and collected ear tissue before releasing them.