Polymorphism of 11 Y Chromosome Short Tandem Repeat Markers among Malaysian Aborigines

The conventional technique such as patrilocality suggests some substantial effects on population diversity. With that, this particular study investigated the paternal line, specifically Scientific Working Group on DNA Analysis Methods (SWGDAM)-recommended Y-STR markers, namely, DYS19, DYS385, DYS389I/II, DYS390, DYS391, DYS392, DYS393, DYS438, and DYS439. These markers were tested to compare 184 Orang Asli individuals from 3 tribes found in Peninsular Malaysia. As a result, the haplotype diversity and the discrimination capacity obtained were 0.9987 and 0.9076, respectively. Besides, the most diverse marker was DYS385b, whereas the least was DYS391. Furthermore, the Senoi and Proto-Malay tribes were found to be the most distant, whereas the Senoi and Negrito clans were almost similar to each other. In addition, the analysis of molecular variance analysis revealed 82% of variance within the population, but only 18% of difference between the tribes. Finally, the phylogenetic trees constructed using Neighbour Joining and UPGMA (Unweighted Pair Group Method with Arithmetic Mean) displayed several clusters that were tribe specific. With that, future studies are projected to analyse individuals based on more specific sub-tribes.

Distribution of cytokine gene polymorphisms in six Orang Asli subgroups in Peninsular Malaysia

Cytokines are involved in immune responses and the pathogenesis of various diseases. Allelic variations within the genes coding for various ∼30 kDa cytokine protein/glycoproteins have been reported for many populations and have been the subjects of many ancestry and health analyses. In this study, we typed 22 single nucleotide polymorphisms (SNPs) in 13 cytokine genes of 165 Orang Asli individuals by using sequence specific primer-polymerase chain reaction (SSP-PCR) assay. The volunteers came from all across the Peninsular of Malaysia and belong to six Orang Asli subgroups; Batek, Kensiu, Lanoh, Che Wong, Semai and Orang Kanaq. Here we report our general findings and original genotype data and their associated analyses (Hardy-Weinberg proportions, estimation of allele and haplotype frequencies) can be found in the supplementary files and will be held at Allele Frequency Net Database (AFND).

Unravelling the genetic history of Negritos and indigenous populations of Southeast Asia

Indigenous populations of Malaysia known as Orang Asli (OA) show huge morphological, anthropological, and linguistic diversity. However, the genetic history of these populations remained obscure. We performed a high-density array genotyping using over 2 million single nucleotide polymorphisms in three major groups of Negrito, Senoi, and Proto-Malay. Structural analyses indicated that although all OA groups are genetically closest to East Asian (EA) populations, they are substantially distinct. We identified a genetic affinity between Andamanese and Malaysian Negritos which may suggest an ancient link between these two groups. We also showed that Senoi and Proto-Malay may be admixtures between Negrito and EA populations. Formal admixture tests provided evidence of gene flow between Austro-Asiatic-speaking OAs and populations from Southeast Asia (SEA) and South China which suggest a widespread presence of these people in SEA before Austronesian expansion. Elevated linkage disequilibrium (LD) and enriched homozygosity found in OAs reflect isolation and bottlenecks experienced. Estimates based on N_e and LD indicated that these populations diverged from East Asians during the late Pleistocene (14.5 to 8 KYA). The continuum in divergence time from Negritos to Senoi and Proto-Malay in combination with ancestral markers provides evidences of multiple waves of migration into SEA starting with the first Out-of-Africa dispersals followed by Early Train and subsequent Austronesian expansions.