(CNN)This dog can sing ... or at least it can yodel.
The New Guinea singing dog, an extremely rare breed, is best known for its unique barks and howls -- it's able to make harmonic sounds that have been compared to the calls of a humpback whale.
Only around 200 captive singing dogs live in conservation centers or zoos, the descendants of a few wild dogs captured in the 1970s. The animals are severely inbred due to a lack of new genes.
None had been seen in their natural habitat for half a century until 2016, when an expedition located and studied 15 wild dogs in the remote highlands of the western side of New Guinea, known as Papua, in Indonesia. A new expedition returned to the study site in 2018 to collect detailed biological samples to confirm whether these highland wild dogs truly are the predecessors of the singing dogs.
A comparison of DNA extracted from blood collected from three of the dogs suggested they have very similar genome sequences and are much more closely linked to each other than any other canine, according to research published on Monday in the journal PNAS.
While their genomes weren't identical, the researchers believed the highland dogs are the wild and original New Guinea singing dog population, with the difference down to physical separation for several decades and inbreeding among the captive New Guinea singing dogs.
"They look most related to a population of conservation biology new guinea singing dogs that were descended from eight dogs brought to the United States many, many, many years ago," said Elaine Ostrander, a distinguished investigator at the National Institutes of Health and senior author of the paper.
"The conservation dogs are super inbred; (it) started with eight dogs, and they've been bred to each other, bred to each other, and bred to each other for generations -- so they've lost a lot of genetic diversity."
The highland wild dogs had a 70% genetic overlap