blood group and malarial parasite infectivity. Results showed a total absence of both Fya and Fyb antigens in two areas (Kadamtala and R.K Nallah) and low prevalence of both Fya antigen in another two areas (Jirkatang and Tirur). There was an absence of malarial parasite Plasmodium vivax infection though Plasmodium falciparum infection was present in 27·59% of cases. A very high frequency of Fy (a–b–) in the Jarawa tribe from all the four jungle areas of Andaman Islands along with total absence of P. vivax infections suggests the selective advantage offered to Fy (a–b–) individuals against P. vivax infection. External genetic affinity Genetic studies have revealed that the Andamanese people are relatively closely related to the indigenous South Asian hunter-gatherers, often termed "Ancient Ancestral South Indians" (AASI). The Andamanese also show high affinity to other Australasian populations (AA), such as Melanesians, as well as to East/Southeast Asian peoples (ESEA). Phylogenetic data suggests that an early initial eastern lineage trifurcated, and gave rise to Australasians (Oceanians), the AASI and Andamanese, as well as East/Southeast Asians, although Oceanians (Papuans and Aboriginal Australians) may have also received some geneflow from an earlier group (xOoA), around 2%, next to additional archaic admixture in the Sahul region. While the Andamanese are often used as proxy for AASI ancestry, a study by Yelmen et al. (2019) argues that isolated South Indian tribal groups, such as the Paniya, Kharia, or Soliga people, would serve as a better proxy for AASI ancestry. Overall, the Malaysian Negritos (Semang), such as the Maniq people, Jahai people, and Batek people, are the closest modern living relatives of the Andamanese people. When compared with ancient DNA samples, Andamanese peoples are closest to the pre-Neolithic Hoabinhians in Mainland Southeast Asia (covered by two samples from Malaysia and Laos). Y-DNA The male Y-chromosome in humans is inherited exclusively through paternal descent. All sampled males of Onges (23/23) and Jarawas (4/4) belong to a sublineage of D-M174(D1a3). However, male Great Andamanese do not appear to carry these clades. A low resolution study suggests that they belong to haplogroups K, L, O and P1 (P-M45). A 2017 study by Mondal et al. finds that the Y-chromosome of the Riang people (a Tibeto-Burmese population), sublineage D1a3 (D-M174*) and the Andamanese D1a3 (*D-Y34637) have their nearest related lineages in East Asia, splitting about 23,000 years ago from an East Asian-related population. The Jarawa and Onge shared this D1a3