September 9, 2020Basic Biology
The New Guinea singing dog was first studied in 1897, and became known for their unique and characteristic vocalization, able to make pleasing and harmonic sounds with tonal quality. Only 200-300 captive New Guinea singing dogs exist in conservation centers, with none seen in the wild since the 1970s. However, the New Guinea singing dog, thought to be extinct for 50 years, still thrives and still stealthily wanders in the Highlands of New Guinea.
In a study published in PNAS (31 August 2020), using conservation biology and genomics, it was discovered that New Guinea singing dog population is opening new doors that can teach biologists about human vocal learning, and can be utilized as a valuable and unique animal model for studying how human vocal disorders arise and finding potential treatment opportunities.
According to the authors, a large amount of inbreeding within captive New Guinea singing dogs changed their genomic makeup by reducing the variation in the group's DNA. Such inbreeding is why the captive New Guinea singing dogs have most likely lost a large number of genomic variants that existed in their wild counterparts. This lack of genomic variation threatens the survival of captive New Guinea singing dogs. Their origins, until recently, had remained a mystery. Another New Guinea dog breed found in the wild, called the Highland Wild Dog, has a strikingly similar physical appearance to the New Guinea singing dogs. Considered to be the rarest and most ancient dog-like animal in existence, Highland Wild Dogs are even older than the New Guinea singing dogs.
It was previously hypothesized that the Highland Wild Dog might be the predecessor to captive New Guinea singing dogs, but the reclusive nature of the Highland Wild Dog and lack of genomic information made it difficult to test the theory. In 2016, in collaboration with the University of Papua, the New Guinea Highland Wild Dog Foundation led an expedition to Puncak Jaya, a mountain summit in Papua, Indonesia. They reported 15 Highland Wild Dogs near the Grasberg Mine, the largest gold mine in the world. A follow-up field study in 2018 allowed for the collection of blood samples from three Highland Wild Dogs in their natural environment as well as demographic, physiological and behavioral data.
According to the authors, the New Guinea singing dogs and the Highland Wild Dogs do not have identical genomes because of their physical separation for several decades and due to the inbreeding among captive New Guinea singing dogs -- not because they are different breeds. In fact, it has been suggested that the vast genomic similarities between the New Guinea singing dogs and the Highland Wild Dogs indicate that Highland Wild Dogs are the wild and original New Guinea singing dog population. Hence, despite different names, they are, in essence, the same breed, proving that the original New Guinea singing dog population are not extinct in the wild.
The authors believe that because the Highland Wild Dogs contain genome sequences that were lost in the captive New Guinea singing dogs, breeding some of the Highland Wild Dogs with the New Guinea singing dogs in conservation centers will help generate a true New Guinea singing dogs population. In doing so, conservation biologists may be able to help preserve the original breed by expanding the numbers of New Guinea singing dogs.
Although New Guinea singing dogs and Highland Wild Dogs are a part of the dog species Canis lupus familiaris, it was found that each contain genomic variants across their genomes that do not exist in other dogs that we know today.
The authors also aim to study New Guinea singing dogs in greater detail to learn more about the genomics underlying vocalization (a field that, to date, heavily relies on birdsong data). Since humans are biologically closer to dogs than birds, by studying the New Guinea singing dogs, it is hoped to gain a more accurate insight into how vocalization and its deficits occur, and the genomic underpinnings that could lead to future treatments for human patients.