Negrito

A Negrito man with a hunting bow (c. 1900) from Negros Island, Philippines

The main paternal haplogroup of the Negritos is K2b in the form of its rare primary clades K2b1* and P* (a.k.a. K2b2* or P-P295*). Most Aeta males (60%) carry K-P397 (K2b1), which is otherwise uncommon in the Philippines and is strongly associated with the indigenous peoples of Melanesia and Micronesia. Basal P* is rare outside the Aeta and some other groups within Maritime Southeast Asia.[10]

Some Negrito populations are Haplogroup D-M174*, a branch of D-M174 among Andaman Islanders, as well as Haplogroup O-P31 which is also common among the now Austroasiatic-speaking Negrito peoples, such as the Maniq and the Semang in Malaysia.[11] The Onge and all the Adamanan Islanders belong strictly to the mitochondrial Haplogroup M it is also the predominant marker of other Negrito tribes as well as Aboriginal Australians and Papuans.[12] Analysis of mtDNA, which is inherited exclusively by maternal descent, confirms the above results. All Onge belong to mDNA M, which is unique to Onge people.[13][14] M is the most common mtDNA haplogroup in Asia,[15]

A 2009 study by the Anthropological Survey of India and the Texas Biomedical Research Institute identified seven genomes from 26 isolated "relic tribes" from the Indian mainland, such as the Baiga tribe, which share "two synonymous polymorphisms with the M42 haplogroup, which is specific to Australian Aborigines". These were specific mtDNA mutations that are shared exclusively by Australian aborigines and these Indian tribes, and no other known human groupings.[16]

Bulbeck (2013) shows the Andamanese maternal mtDNA is entirely mitochondrial Haplogroup M.[17][18] Super-haplogroup M is distributed all over Asia, where it represents 60% of all maternal lineages.[19] Their Y-DNA belongs to the D haplogroup, which has only been found in Japan and Tibet at low frequencies outside of the Andaman Islands, a fact that underscores the insularity of these tribes.[12]

A study of human blood group systems and proteins in the 1950s suggested that the Andamanese peoples were more closely related to Oceanic peoples than African pygmy peoples. Genetic studies on Philippine Negritos, based on polymorphic blood enzymes and antigens, showed that they were similar to their surrounding populations.[20]

Negrito peoples may descend from the first settlers of South and Southeast Asia. Despite being isolated, the different peoples do share genetic similarities with their neighboring populations.[20][21] They also show relevant phenotypic (anatomic) variations which require explanation.[21]

A young Onge mother with her baby (Andaman Islands, India, 1905)

This has often been interpreted to the effect that they are remnants of the original expansion from Africa some 70,000 years ago. Studies in osteology, cranial shape and dental morphology have connected the Semang to Australoid populations, while connecting the Andamanese to Africans in craniometry and to South Asians in dental morphology, and Philippine Negritos to Southeast Asians. A possible conclusion of this is that the dispersal of mitochondrial haplogroup B4a1a is connected to the distinction between Philippine and other Negritos.[17] However, another study suggests that the Onge (indigenous to Little Andaman) are more closely related to Southeast Asian Negritos, Melanesians, and Southeast Asians than they are to present-day South Asians, and that the Great Andamanese (of the northern Andamans, as opposed to the Onge or other Andamanese groups) "appear to have received a degree of relatively recent admixture from adjacent regional populations but also share a significant degree of genetic ancestry with Malaysian negrito groups".[22]

Principal Component analysis of Australo-Melanesians with world populations (Aghakhanian et al. 2015)

A recent genetic study found that unlike other early groups in Oceania, Andamanese Negritos lack Denisovan hominin admixture in their DNA. Denisovan ancestry is found among indigenous Melanesian and Aboriginal Australian populations at between 4–6%.[23][24]

Some studies have suggested that each group should be considered separately, as the genetic evidence refutes the notion of a specific shared ancestry between the "Negrito" groups of the Andaman Islands, the Malay Peninsula, and the Philippines.[25] Indeed, this sentiment is echoed in a more recent work from 2013 which concludes that "at the current level of genetic resolution ... there is no evidence of a single ancestral population for the different groups traditionally defined as 'negritos'.[22]

Recent studies, concerning the population history of Southeast Asia, suggest that most modern Negrito populations in Southeast Asia show a rather strong Eastern Eurasian admixture (Austronesian and Austroasiatic), ranging between 30% to 50% of their ancestry.[26]

Chaubey et al. 2013 notes that the Andamanese people are closely related to other Negrito populations as well as Melanesians.[27]

According to Basu et al. (2016), Andamanese and other Negrito populations are closely related and share also partial relation to Indigenous people of New Guinea.[1]

An Ati woman of Kalibo, Philippines in 2006

Based on superficial similarities of a number of physical features – such as short stature, dark skin, scant body hair, and occasional steatopygia (large, curvaceous buttocks and thighs) – some scholars suggested a common origin for the Negrito and the Pygmies of Central Africa. The claim that the Andamanese more closely resemble African pygmies than other Austronesian populations in their cranial morphology in a study of 1973 added some weight to this theory, before genetic studies pointed to a closer relationship with their neighbours.[20]

Multiple studies also show that Negritos share a closer cranial affinity with Aboriginal Australians and Melanesians.[28][29]