ABSTRACT
The population history of Aboriginal Australians remains largely uncharacterized. Here we generate high-coverage genomes for 83 Aboriginal Australians (speakers of Pama-Nyungan languages) and 25 Papuans from the New Guinea Highlands. We find that Papuan and Aboriginal Australian ancestors diversified 25-40 thousand years ago (kya), suggesting pre-Holocene population structure in the ancient continent of Sahul (Australia, New Guinea and Tasmania). However, all of the studied Aboriginal Australians descend from a single founding population that differentiated ~10-32 kya. We infer a population expansion in northeast Australia during the Holocene epoch (past 10,000 years) associated with limited gene flow from this region to the rest of Australia, consistent with the spread of the Pama-Nyungan languages. We estimate that Aboriginal Australians and Papuans diverged from Eurasians 51-72 kya, following a single out-of-Africa dispersal, and subsequently admixed with archaic populations. Finally, we report evidence of selection in Aboriginal Australians potentially associated with living in the desert.
Subject(s)
Genome, Human/genetics , Genomics , Native Hawaiian or Other Pacific Islander/genetics , Phylogeny , Racial Groups/genetics , Africa/ethnology , Australia , Datasets as Topic , Desert Climate , Gene Flow , Genetics, Population , History, Ancient , Human Migration/history , Humans , Language , New Guinea , Population Dynamics , TasmaniaABSTRACT
OBJECTIVES: The population history of European Romani is characterized by extensive bottleneck and admixture events, but the impact of this unique demographic history on the genetic risk for disease remains unresolved. METHODS: Genome-wide SNP data on Romani, non-Romani Europeans and Indians were analyzed. The excess of homozygous variants in Romani genomes was assessed according to their potential functional effect. We also explored the frequencies of risk variants associated with five common diseases which are present at an increased prevalence in Romani compared to other Europeans. RESULTS: Slightly deleterious variants are present at increased frequencies in European Romani, likely a result of relaxed purifying selection due to bottlenecks in their population history. The frequencies of SNPs associated with common metabolic and cardiovascular diseases are also increased compared to their European hosts. CONCLUSIONS: As observed in other founder populations, we confirm the impact of bottlenecks on the abundance of slightly deleterious variants in Romani groups, probably including metabolic and cardiovascular risk variants.