Genetically, the Onge, as well as other Andamanese people, are distantly related to
East Asian people. The Andamanese Onge show the highest affinity towards some Southeast Asian
Negrito ethnic groups, such as the
Aeta people, but also ancient remains of
Hoabinhians, which are all characterized by Basal East Asian ancestry. It was found that Andamanese (Onge) split from the common ancestor of modern day East Asians between 50,000 BC and 25,000 BC, before becoming isolated on the
Andaman Islands. The Andamanese (Onge) as well as East Asians, are also distantly related to Ancient Ancestral South Indians, a proposed ancient indigenous lineage of
South Asia. Recent genetic evidence suggest that a Basal East Asian population (close or ancestral to Andamanese and East Asians) was widespread in
Asia. Onge-related ancestry, however, is found to peak in ancient coastal East Asia and is relatively rare further inland. Onge are also closely related to
Papuans and
Aboriginal Australians but differ due to the absence of Denisovan ancestry found in the latter two. Other studies detected Denisovan and Neanderthal input in the Onge although it is much lower than what's found in Papuans and Aboriginal Australians. Overall, despite their affinities, there was a simultaneous split between the Onge, Asian (including Han, Indigenous Taiwanese and Thai) and Near Oceanian (including Aboriginal Australians and Melanesians) lineages after the initial eastward migration of an
ancient eastern lineage from the
Iranian Plateau. A study by Reich et al. (2009) found that while the Onge are distantly related to modern South Asians, they have none of the admixture from
Neolithic Iranian farmers or
steppe pastoralists which is widespread on the mainland. From this, they conclude that the Onge are solely descended from one of the ancient populations which contributed to the genetics of modern Indians. According to Chaubey and Endicott (2013), overall, the Andamanese are more closely related to Southeast Asians and East Asians than they are to present-day South Asians. According to Yelmen et al. 2019, the non-West Eurasian part extracted from South Asian samples, especially from certain South Indian tribal groups, are a better proxy for Ancient Ancestral South Asian (AASI) ancestry than the Andamanese Onge are. There is also evidence of deep divergence between the AASI lineage and the ancestry found in present Onge. According to a 2023 study,
Great Andamanese are found to be ancestral to the Onge and
Jarawa groups. The Onge's physical similarities with indigenous
African groups are reflective of adaptation to tropical rainforests and
convergent evolution rather than shared ancestry. The Onge population is consistently declining and infant mortality rate is very high. Several physiological parameters such as ABO, Rh blood group, blood pressure, SGOT, SGPT and total protein level, Hepatitis B surface antigen, VDRL and some genetic markers have been conducted. The results of blood pressure, cholesterol level and liver enzyme test do not show any abnormality. However, the incidence of HbsAg is found to be very high that might have affected their fertility. Analysis of paternal lineages indicates that all Onge carry the Y-DNA
Haplogroup D, widespread in
East Asia and less in
Central Asia. Maternally, the Onge also exclusively belong to the
M clade, bearing the M2 and M4 subclades, commonly found in Asia. The immunoglobulin levels (G, M and A) have been studied and found to be quite high compare to other Indian and world populations. The increase level of immunoglobulins in the Onge might have resulted to frequent exposure to different kind of infections and diseases. == References ==