East Asia

The most recent worldwide population tree published by Luca Cavalli-Sforza and Marcus Feldman (2003), based on analysis of polymorphisms in 120 protein systems in 1915 human populations, groups Southeast Asians with Pacific Islanders (excluding New Guinea), and then at a higher level with New Guineans and Australian Aborigines. A completely separate extra-African group, comprising the rest of out-of-Africa mankind, includes Northeast Asians, American Indians, and Europeans. Such high-level groupings do not inform greatly about the issues under debate here and probably reflect mainly Pleistocene movements of modern humans, in two spread processes into northern and southern East Asia respectively. Subsequent expansions of farming populations have been essentially confined to within each of these two zones rather than across both, the only exception in prehistoric times perhaps being the expansion of Tibeto-Burman speakers into Southeast Asia. Much, of course, depends on where one places the boundary between northern and southern East Asia - presumably in terms of this analysis it falls somewhere in central China, north of the regions whence the dispersals of Austroasiatic, Tai, Hmong-Mien, and Austronesian peoples are claimed to have begun (Figure 10.8B). Tatiana Karafet and colleagues (2001) also underline distinctions between Northeast and Southeast Asian populations in Y-chromosome haplogroups, linking central Asian Turkic populations and Tibeto-Burman speakers to Northeast Asians.'

In contrast to the above, Peter Underhill and colleagues (2001 a) imply closer northsouth Asian relationships in terms of the spread of group VII Y- chromosome lineages, stating that that they probably originated in northern China and spread with millet and rice agriculture on a large scale, analogous to the spread of group III lineages by Bantu-speakers. Group VII lineages dominate all of the East Asian mainland, from northern China to Thailand.

This observation of close relationships right through East Asia is supported very strongly by analyses of ancient crania. Johan Kamminga and Richard Wright (1988) have observed that Late Paleolithic crania from China, particularly from the Upper Cave at Zhoukoudian, were not morphologically

ancestral to the modern East Asian population, raising the possibility that the latter spread from an unknown homeland in Neolithic times. These Paleolithic people instead resembled the pre Japanese Jomon population of Japan between about 12,000 and 2,000 years ago, prior to the arrival there of Yayoi rice farmers. In China, fully Mongoloid cranial features first appear in the early Neolithic, for instance at the site ofJiahu in the Huai valley (Chen and Zhang 1998). Peter Brown (1998, 1999) extends these observations to the whole of China, contending that Paleolithic skulls such as those from Liujiang and Minatogawa, as well as Upper Cave, are not Mongoloid at all, whereas Neolithic samples from sites such as Dawenkou, Jiangzhai (Yangshao culture), and Jiahu most certainly are.

Considerable population replacement during the Chinese Neolithic is therefore indicated from the skeletal perspective, as likewise during the expansion of Yayoi rice agriculturalists from Korea into Japan at about 300 BC (Hudson 1999, 2003). The genetic perspective seems to differ, and debate will doubtless continue.

Southeast Asia and Oceania (mainly

Austronesians)

A great deal of the genetic and skeletal research in this region has been driven by a scholarly obsession with the origins of the Polynesians. I have already summarized elsewhere the results of much of this research (Bellwood 1978a, 1993, 1997a ), concluding that pre-Neolithic populations in Island Southeast Asia, especially Indonesia, formed a westerly extension of the Australomelanesian population that had been established in the western Pacific (including Australia) since at least 40,000 years ago. Neolithic population movements, especially of Austronesian speakers into the islands and of Austroasiatic speakers on the Southeast Asian mainland, then brought in Asian (Southern Mongoloid) genotypes that mixed with those of the preceding populations, being even absorbed by them in Island Melanesia and to a lesser extent in the Malay Peninsula and eastern Indonesia. The result is that today one can see a cline from Asian into Australomelanesian characteristics running from north to south and from west to east, from Island Southeast Asia into Island Melanesia, and southward down the Malay Peninsula. The cline from Melanesia into Polynesia trends in the opposite direction, with Asian characters coming back in high proportion as one moves into eastern Polynesia and eastern Micronesia.

Figure 11.2 Diagram of relationships between Asian and Oceanic populations based on a cluster analysis of 29 cranial measurements recorded on 53 male samples. The samples are of various dates from possibly Neolithic and Bronze Age to relatively recent. From Pietrusewsky and Chang 2003.

The peoples of New Guinea, despite developing very early and independent

agriculture, cannot really be shown to have expanded very far in a geographical sense, except in terms of genetic contribution to many present-day Austronesian speakers in eastern Indonesia (especially Moluccas and eastern Lesser Sundas) and Island Melanesia, eastward to Fiji. Recent mtDNA research does, however, indicate a lack of lineage diversity in the New Guinea Highlands that could relate to agriculturally driven population dispersal (Hagelberg et al. 1999:149).

The most complete analysis of East Asian and Oceanic cranial data is that by Michael Pietrusewsky (1999), whose cluster analysis (shown in Figure 11.2) expresses not just geographical but also phylogenetic relationships. In East Asia, this tree clearly separates Jomon and Ainu populations from Japanese. It also indicates the fairly high degree of diversity present in "Chinese" samples, and links all Southeast Asians with these in a large Asian branch at the top of the diagram. Close to this Asian branch come Polynesians and Micronesians, with Melanesians and Australians having very different cranial characteristics and belonging in a separate branch of their own. Perhaps most interestingly, in view of the discussion to follow, is Pietrusewsky's recent conclusion (Pietrusewsky and Chang 2003:293) that "Connections between Taiwan aboriginal groups and cranial series from Polynesia suggest that Taiwan's aboriginal inhabitants may have been the ancestral source of these inhabitants of remote Oceania." It is also worth noting that the deep divisions between East and Southeast Asians favored by some geneticists (above) are not visible in these cranial data.

We now move to the genetics, beginning with the broad question of Austronesian origins and dispersals and picking up the thread in 1995 when Alan Redd, Terry Melton, and colleagues published their analyses of the distribution of a feature within mtDNA known as the 9-base-pair deletion (Redd et al. 1995; Melton et al. 1995). This deletion contains a number of lineages defined by specific nucleotide substitutions. One, involving a substitution at position 16247, has become known as the "Polynesian motif" because it dominates in most modern Polynesian populations. Redd and colleagues suggested that this lineage spread from eastern Indonesia into Oceania at about 5,500 years ago. The ultimate source of the Austronesians as a whole, and of the substitution at position 16261 that occurred prior to 16247, was stated to be Taiwan, a view reached independently at the same time by Bryan Sykes and colleagues (1995), also using mtDNA data. Terry Melton and colleagues (1998)

reemphasized that the ancestral mtDNA substitutions (excluding 16247) within the 9-base-pair deletion haplogroup had spread into Southeast Asia and Oceania through a Taiwan bottleneck (see also Hagelberg et al. 1999; Hagelberg 2000).

These conclusions are in accord with those of several other biochemists and geneticists. Koji Lum and Rebecca Cann (1998) have noted that Polynesian mtDNA very clearly links these people with Southeast Asians rather than Melanesians, a conclusion also drawn by Andrew Merriwether and colleagues (1999), who stress very firmly that Polynesian maternal ancestry cannot be derived to any major degree from Melanesia. All authorities agree that the Polynesian mtDNA motif (with the 16247 substitution) originated in eastern Indonesia rather than in Taiwan, where only the antecedent mutations are present, a situation suggesting that the mutation might have occurred during the dispersal process itself.

By 1998, Koji Lum and colleagues (1998, 2002) were already noting that about 30 percent of Polynesian nuclear genes are probably Melanesian, and this they related to extensive male gene flow from Papuan into Austronesian communities as the Austronesian dispersal progressed eastward. In a sense, the mtDNA story was beginning to look like an "express train" from Southeast Asia into the Pacific, to use the metaphor of Jared Diamond (1988), whereas the nuclear DNA and (later on) the Y-chromosome stories would be seen to relate more to Darwin's "entangled bank" metaphor as used by John Terrell (1988). Women traveled early and far with the initial migrants, but their female descendants stayed essentially in place, whereas males have always had a propensity to roam (Hage and Marck 2003 discuss these observations from an anthropological perspective).

The concept of considerable male-mediated gene flow from Papuan into Austronesian populations in Oceania was soon given further stimulus by Y- chromosome research. Manfred Kayser and colleagues (2000) claimed that three Polynesian Y-chromosome haplotypes found in a small sample of Cook Islanders could have originated in Melanesia, even though they also occur in island Southeast Asia. Their conclusions differed from those presented in another study by Bing Su and colleagues (2000), who regarded all Polynesian Y-chromosomes as being derived from Southeast Asia, with none at all from Melanesia. Such difficulties reflect in part an analysis of different markers by the different research teams, and Kayser states that the results of both analyses

could be compatible.

One such compatible conclusion was announced in 2001, when Cristian Capelli and colleagues (2001) provided an overall Y-chromosome view of Pacific, Southeast Asian, and southern Chinese relationships. Austronesian dispersal from southern China and Taiwan into Island Southeast appears to be well recorded by their Y haplogroups H and L (now more commonly termed 03: Cox 2004), the latter having an apparent origin during the early Holocene and occurring widely and frequently in South China, southern Taiwan, Island Southeast Asia, and Polynesia. Eastern Indonesians and Melanesians have haplogroups that are mainly indigenous to the western Pacific region (Cox 2004). Polynesians reveal great variation as a result of genetic drift, but basically they combine both the Melanesian and the "Austronesian" haplogroups in proportions that differ from one island group to another.

All the Y-chromosome information on Austronesians presented so far fits quite well with what we can read from the archaeology and linguistics. An expanding population with Y-chromosome haplogroups that probably originated in southern China/Taiwan mixed increasingly with indigenous populations as it moved southward and eastward, virtually disappearing eventually in a genetic sense in Island Melanesia, but continuing eastward again through a series of founder bottlenecks into Polynesia. Using a different set of Y-chromosome data, Peter Underhill and colleagues (2001b) state: "The Y- chromosome results support a pattern of complex interrelationships between Southeast Asia, Melanesia, and Polynesia, in contrast to mtDNA and linguistic data, which uphold a rapid and homogeneous Austronesian expansion. The Y- chromosome data highlight a distinctive gender-modulated pattern of differential gene flow in the history of Polynesia." Matthew Hurles and colleagues, working with satellite markers within the Y-chromosome, provide the additional conclusion: "[our] study, while not strongly supporting the hypothesis of a rapid Austronesian expansion from Taiwan, is not necessarily incompatible with it. Biological and cultural origins can become uncoupled to varying degrees" (Hurles et al. 2002:301; Hurles 2003).

So, can we relax now with a conclusion from genetics that Austronesian prehistory witnessed initial fairly clear-cut dispersal from southern China and Taiwan, via Island Southeast Asia, into Oceania, accompanied by considerable intermixing with indigenous populations, and eventually with a considerable

quantity of male-focused gene flow out of Melanesia? I certainly believe that we can, but a team of mtDNA researchers comprising Martin Richards, Stephen Oppenheimer, and Bryan Sykes have recently stated otherwise (Richards et al. 1998; Oppenheimer and Richards 2001a, 2001b, 2003). They claim that Polynesians are of separate biological origin from other Austronesians, since the "Polynesian motif" can in their opinion be clocked to a mutation in eastern Indonesia that occurred between 5,500 and 34,500 years ago. Because this motif does not appear to occur in its "final" form with the mutation at position 16247 in Taiwan, the Philippines, or much of Indonesia, and because their calculated age range precedes any archaeological or linguistic evidence for Austronesian dispersal, they claim that Polynesians are derived from Pleistocene populations located in eastern Indonesia, perhaps somewhere east of the Wallace Line (Sulawesi, Moluccas, or Lesser Sundas). They also suggest that the whole of the Austronesian dispersal in the linguistic sense might have originated in eastern Indonesia, a hypothesis also foreshadowed in Y chromosome research by Bing Su and colleagues (2000; but see contrary arguments by Reid 2001).

Linguistically and archaeologically, deriving all Austronesian-speaking populations from Pleistocene forebears in eastern Indonesia is not a credible proposition. To claim a biological dispersal of Austronesian-speaking peoples from eastern Indonesia to Taiwan would involve movement in a direction completely opposed to that of the archaeology and the languages. This is no doubt possible, but extremely unlikely given any balanced worldwide comparative view of multidisciplinary human history. But what of the Polynesians and the Polynesian mtDNA motif? There are problems here, since firstly, this motif also occurs in Madagascar in high frequency, a situation that recently led Bryan Sykes (1999b:109) to claim that Madagascar was settled by Polynesians sailing south of Australia. However, not only do the Malagasy languages derive in the main from southern Borneo, but Madagascar prehistory since settlement occurred about AD 500 is fully ceramic, whereas Polynesians lost pottery making about 2,000 years ago. There is absolutely nothing in the archaeological or linguistic records that could possibly bring Malagasy settlers, with their Malay-mediated Sanskrit loans (Adelaar 1995), from Polynesia.

Instead, we seem to have three possibilities to explain the situation recognized by Oppenheimer and Richards with the Polynesian motif:

1.If populations with a Polynesian-like and Asian-derived morphology had spread into eastern Indonesia long before the period of Austronesian dispersal, then the haplotype could have been acquired from them much later by the Austronesian populations ancestral to Polynesians. This is possible in theory, and would allow for a greater level of accommodation between the two opposing reconstructions. The main problem is that there is no skeletal evidence to indicate the presence of such a Polynesian-like population in eastern Indonesia prior to the Holocene, although this may simply reflect lack of data.

2.The molecular clock calculation for the origin of the Polynesian motif may be wrong, given that there is now a voluminous literature of debate and disagreement about this kind of chronological calculation. If wrong, then perhaps the mutation could have occurred during Austronesian dispersal after 4,000 years ago in eastern Indonesia. In other words, is the place of origin of the Polynesian motif correct, but the calculated date of its mutation wrong?'

3.Could early Austronesians have picked up the Polynesian motif from an indigenous source in eastern Indonesia, initially through only one or two female individuals, whose descendants soon thereafter, as a result of considerable fecundity in bottleneck situations, raised the frequency of its occurrence in the ancestral Polynesian (Lapita) population? This option seems possible, but is only necessary if a Pleistocene date for the origin of the Polynesian motif is supported by future calculations.

Oppenheimer and Richards also suggest that the alpha-globin genes of Polynesians (which code for part of the hemoglobin molecule) most likely originated east of the Wallace Line. This may be correct, but since abnormal hemoglobins are involved throughout the tropical Old World in defenses against malaria it seems likely that natural selection lies behind the situation, rather than population origin factors themselves. Eastern Indonesia and Melanesia, even today, still have very virulent forms of malaria, and early Austronesians were probably initially without any genetic variants that confer resistance (Serjeantson and Gao 1995; Fix 2002).

This review of Austronesian genetic ancestry has gone into detail since this region, like Europe, has one of the densest debates between archaeologists, linguists, and biologists currently under way anywhere in the world. As it happens, just after this chapter was drafted, I was asked to read a PhD thesis by Murray Cox (2003), a biochemist from the University of Otago in New Zealand and now based in the Leverhulme Centre for Human Evolutionary Studies in Cambridge. Cox has reviewed the Y and mtDNA data for Austronesians in detail, and points out that, perhaps as expected, modern Austronesians only reveal (so far) about 20 percent of the genes likely to have been carried by their Neolithic Austronesian ancestors, an average situation perhaps similar to that for Europe. But Cox also recalculates the age of the Polynesian motif, bringing it much closer to overlap with the period of Austronesian migration, and of similar Holocene age to Asian Y-chromosome haplogroup 03, as discussed above. Cox clearly favors what he terms a "Modified Out of Taiwan Model" for Austronesian dispersal, which is basically the model that I favor.

Finally, one other region overlapping with Austronesia where there has recently been debate over population history is the Malay Peninsula, with its marked population variations running from southern Thailand toward Singapore. My own view is that three major population movements into the Peninsula are represented in present patterns of diversity (Bellwood 1993, 1997a). The Semang Negritos are descendants of early Hoabinhian foragers who spread widely through the Peninsula, probably moving inland as postglacial sea levels rose in the early Holocene. According to David Bulbeck (2003), they ultimately acquired shorter stature within the past few millennia in the interior rain-forest environment. They were followed by ancestral Senoi farmers who moved down from southern Thailand about 4,000 years ago, bringing Neolithic artifacts and Austroasiatic ("Aslian") languages into the Peninsula, the latter being eventually adopted by the Semang foragers, just as Negritos in the Philippines have adopted Austronesian languages. The ancestors of the third major group, the Austronesian-speaking Malays, arrived during the Iron Age, about 500 BC or later, from western Borneo and/or Sumatra.

This relatively simple series of cultural and biological successions, which in my view still explains the situation best, has also been examined by anthropologist Geoffrey Benjamin (1985). He favors the view that the two Aslian populations are of indigenous Peninsula origin and have basically

differentiated their lifestyles, languages, and phenotypes in situ as a result of social and economic factors (e.g., mobile hunting vs. sedentary farming, group exogamy vs. endogamy, differential involvement in trade). Benjamin's view has recently been upheld by David Bulbeck (2004) from a skeletal perspective. Geneticist Alan Fix (1999, 2000, 2002) also favors Benjamin's hypothesis of internal cultural and biological genesis, but concludes that modem genetic data cannot really prove or disprove the occurrence of ancient migrations, noting on several occasions that history may not be read simply from gene trees.

For what it is worth, genetic research (Saba et al. 1995) suggests that the Semai Senoi of Malaysia and the Khmers of Cambodia are fairly closely related in their blood genetic markers (proteins and enzymes), and if this is an indication of shared ancestry then it is much easier to locate it in prehistoric, perhaps Neolithic times, than in historical times. The Khmer empire of Angkor certainly never stretched as far as the jungled interior of Peninsular Malaysia, and we have no evidence that any significant gene flow into the southern Malay Peninsula occurred as recently as this (ca. 12th century AD). I can only conclude that the Malay Peninsula is still an enigmatic region and simple answers to population history will not come easily.