Genetic Diversity and Historical Divergence of Malays and Indigenous Populations in Peninsular Malaysia and Northern Borneo

Previous studies have highlighted significant genetic structure among Southeast Asian populations, with Northern Borneo natives closely related to Austronesians from Taiwan and the Philippines, and Peninsular Malaysia indigenous populations potentially linked to the indigenous Andamanese. In this study, we analyzed 96 genomes from indigenous populations in Peninsular Malaysia, genotyped with approximately 2 million genome-wide autosomal SNPs, alongside datasets from Singapore cosmopolitan Malays and five native populations from Sabah, Northern Borneo. Our findings reveal distinct genetic structures between indigenous populations and Malays, despite their shared habitat. The Malays exhibit substantial admixture with East Asian, Austronesian, and indigenous Peninsular Malaysian ancestral components. Indigenous populations showed lower within-population diversity and longer linkage disequilibrium compared to benchmark populations. Estimated divergence times suggest that the Semang represent an earlier branching population (∼10,000 years ago), followed by Northern Borneo natives (∼7,600-6,H800 years ago), with Malays diverging more recently. These results support a scenario of successive migration waves into Southeast Asia, providing insights into the genetic history and population structure of the region.