Thursday 21 September 2023

PAG Australia 2023: Exploring Dingo Ecology and Evolution with Chromosome-Level Canid Genomes

Richard J Edwards, Matt F Field and J William O Ballard - PAG Australia 2023

Dogs are uniquely associated with human dispersal and bring novel insight into human migration and the domestication process. Dingoes represent an intriguing case within canine evolution being geographically isolated for thousands of years. The exact origin(s) and people(s) who transported the canines that became dingoes to Australia is debated, but it has been suggested they arrived by boat ~5,000-8,000 BP. Published morphological and genetic evidence has established the presence of at least two dingo lineages. The Alpine dingo is commonly found in south-eastern Australia while the Desert ecotype is found in the north, central and western Australia. The relationship of dingoes to modern dogs, and the ecotypes to each other, has important implications management and protection of this top predator, as well as providing interesting perspectives on human colonisation and canine domestication.

We have generated chromosome-level assemblies of both dingo ecotypes, along with domesticated dogs representing both ancient (Basenji) and derived (German Shepherd) breeds. In each case, long-read sequencing and Hi-C scaffolding have been combined to produce genome assemblies with high contiguity and structural completeness. Comparison of these assemblies with additional dog breeds, using the Greenland wolf as an outgroup, places the dingo as an early offshoot of modern dogs, situated between the grey wolf and the domesticated dogs of today. This is supported by patterns of genetic variation, and chromosome structure. Furthermore, we confirm that dingoes have not experienced the expansion of the AMY2B pancreatic amylase gene that occurred during domestication of modern dogs. This has important implications for dingo ecology and behaviour, and raises the prospect of using AMY2B copy number as a novel and reliable in-field discriminator between dingoes and feral dogs.