Out of Eden: The Peopling of the World

by Oppenheimer, Stephen

  Several other geneticists have also dated local clusters of Asian lines, male and female, that had found their way from mainland East Asia into Southeast Asia and the Pacific. Cambridge geneticist Peter Forster has dated several such colonizing clusters, which may reflect a local population increase in the south-west Pacific. One of these was a local version of the East Asian Haplogroup E, now also found in Malaysia and Sabah (north-east Borneo). He dated the Southeast Asian E cluster to 12,100 years. Another was a sub-clan of major Southeast Asian Haplogroup F, found in Vietnam and Malaysia, which he dated to 9,100 years. Forster also found that one version of Haplogroup B4 had arrived in New Guinea from Asia by 12,500 years ago. All these findings support my view that such East Asian population dispersals in Southeast Asia and to the south-west Pacific were going on continuously from around the time of the LGM and long before the Neolithic revolution. In other words, typically East Asian lines were expanding in the region of Southeast Asia and farther east into Melanesia long before farming could have provided an impetus to the colonization of these regions. Similar post-glacial dates of dispersal are found for intrusive Y chromosomes from East Asia.23

  The dates on their own fail to show the extent of gene flow from Indo-China, through Island Southeast Asia, to Melanesia after the ice age. In 1994, Italian geneticist Antonio Torroni and colleagues made a significant breakthrough by identifying seven East Asian maternal clans, labelled A–G, all present in Tibet and to varying degrees on other parts of the mainland (for A–G, see Chapter 5). Together with a recently identified deep East Asian line, M7, these seven East Asian genetic groups were found in 85 per cent of Koreans, 79 per cent of southern Han Chinese, 75 per cent of Vietnamese, 25 per cent of Malays, 44 per cent of people from Sabah, and 20 per cent of New Guineans in the survey.24

  Such a steady decline in Southeast Asian maternal lines as we go from East Asia to New Guinea implies a progressively higher proportion of indigenous lines the farther we go from Asia. The groups in Torroni’s study that had the least identifiable typical East Asian lines, however, were back in mainland Southeast Asia. These were the Orang Asli, the aboriginal peoples of the jungle interior of the Malay Peninsula.

  Martin Richards and I, with Malaysian colleagues, were recently able to confirm this picture in a much more detailed study of the Orang Asli (see also Chapter 5). The two key aboriginal groups least affected by recent immigration are the Semang and the Aboriginal Malays. The former have only 22 per cent typical East Asian genetic lines in their make-up. This is consistent with the view that the Negrito Semang are a very isolated relict people. However, there was an unexpected surprise when it came to the Southern Mongoloid Aboriginal Malays. While only a quarter of the latter have typical East Asian lines, another half were composed of two major ancestral Asian branches. One of these two (accounting for a quarter of lines) arose just before, but on the same branch as, the Eurasian ancestral Nasreen supergroup. In other words, she was a twin sister to Nasreen, one of the two daughters of Out-of-Africa Eve. This ancestral ‘pre-Nasreen’ had never been found before. Another surprise was that a further quarter of lines belonged to a pre-F branch. Since F is a major maternal founder line for East and Southeast Asia, this strongly supports the idea put forward in Chapter 5 that such Southern Mongoloid populations represent the ultimate geographical and genetic Mongoloid homeland.25

  Coming back to the period around the LGM, these exciting new genetic findings are consistent with the view of today’s isolated Aboriginal Malays and Semang being the least admixed, and hence closest to Malay Peninsular types before the Mongoloid expansions from farther north. Just how much real Northern Mongoloid intrusion of maternal lines actually occurred more recently among Southeast Asian populations remains to be seen.

  As a demonstration of a tendency for higher male intrusion across international boundaries, typical mainland East Asian Y-chromosome markers as defined by the single marker Ho (see Chapter 5) completely dominate Indo-China and Island Southeast Asia, ranging from 54 to 97 per cent, in different parts of the region, with a sharp fall-off across Wallace Line (the Wallace Line marks the south-eastern limit of the Sunda continent dividing it, and the rest of Asia, from the islands of Eastern Indonesia, New Guinea and Australia – shown in Figures 5.3 and 6.4). However, since Ho probably originated in Southeast Asia, there is no reason to suppose that his dominance reflects Northern Mongoloid intrusion rather than simply re-expansion from Southeast Asia after the LGM.26

  The genetic evidence thus supports the idea that East Asian lines expanded south within Southeast Asia, starting from 18,000 years ago (the LGM) and continue to do so even today. This goes a long way to explaining the varying mixtures of Mongoloid and non-Mongoloid features among the present numerically dominant Southern Mongoloid peoples of Southeast Asia right up to the limit of the Wallace Line.

  The non-Mongoloid ‘Negritos’, with their undifferentiated dentition (the Semang – see Chapter 5) of the Central Malaysian jungle would then represent isolated, relatively unmixed relict populations derived from the original beachcombers before the Mongoloid expansions. The Semang were presumably left as central genetic islands in the dense jungle, as the invaders flowed around them.

  The other isolate, the Aboriginal Malays of the Malayan jungle, give dental and genetic clues to the ancestral relationship between the Sundadonts of Southeast Asia and the Sinodont populations farther north.

  Physical evidence for the earliest Mongoloid dispersals in Southeast Asia

  The most recent archaeological development of note is the discovery of Mongoloid skeletal remains in Song Keplek, a cave in Gunung Sewu, Java, dated to 7,000 years ago. This was a time long before rice began to be cultivated in Indonesia, and thus challenges the orthodoxy that Mongoloid intrusion to Island Southeast Asia coincided with the arrival of rice agriculture. From the LGM up until about 10,000 years ago, there was no sea barrier to Mongoloid spread until they reached the Wallace Line at Bali. When the Mongoloid intruders reached Bali and Borneo, having walked all the way from Asia, they would have faced a sea crossing. This was not an insuperable barrier, as we know from the exploits of the early Australians, but it surely must have slowed the flow of population and genes (see Figure 6.4). Accordingly, Eastern Indonesia, on the other side of the Wallace Line is a boundary zone, with some groups showing Negrito features and others Mongoloid. By the time we cross to New Guinea, on the other side of a transition zone formed by the Moluccas and the other scattered islands of Eastern Indonesia, most local inhabitants possess characteristically Melanesian frizzy hair and dark skin (see Plate 17). The people of New Guinea are by several measures morphologically similar to the Negritos of the Malay Peninsula, thousands of kilometres to the west.27

  Despite the picture I have painted so far, there is an orthodoxy that until recently Southeast Asia was inhabited only by Australo-Melanesian hunter-gatherers. Given the shortage of human remains of any description on the remaining landmasses after the post-glacial rise in sea level, this assumption remains the view of many. What evidence there is does not support the Australo-Melanesian view. At the moment, the oldest documented skeletal legacy of Anatomically Modern Humans anywhere in Southeast Asia is the famous ‘deep skull’ from Niah Caves in Borneo. Carbon-dated to around 42,000 years ago, this skull has in the past been described as ‘gracile Australo-Melanesian’, more particularly as being like the now extinct Tasmanians. But as Australian physical anthropologist-cum-archaeologist David Bulbeck points out, the relatively gracile Tasmanians were not typically Australoid or Melanesian, and the Niah skull, like Tasmanians, shows instead a similarity with the aboriginal Ainu of Japan. Bulbeck drew a similar conclusion for another ancient skull, this time a partial skull from Tabon Cave in the Philippines, dated to around 20,000 years.28

  Two famous human skulls found at the end of the nineteenth century at Wajak in Central Java have provided a focus for a number of different reconstructions of the human prehistory of the region. For more than a century, these skulls
were thought to predate the LGM and to have represented an early proto-Australian type. However, a complete reverse of this Australo-Melanesian view has been put forward by a number of anthropologists who have pointed out that the Wajak skulls show no similarities to Australians of any antiquity. Instead, the skulls have been claimed to be early Mongoloid, or even identical to but more robust than modern (Mongoloid) Javanese. Most convincingly, David Bulbeck argues that they too are like the Ainu and are part of a Pacific coast/Sundaland continuum. While early reports insisted that the Wajak skulls were Pleistocene – older (or much older) than 10,000 years, two recent carbon dates suggest that they are either 10,560 or 6,560 years old, which puts them more in the pre-agricultural early Holocene.29

  Clearly, the possibility that the Niah, Tabon, and Wajak skulls may be evidence of the early presence of early Mongoloid or pre-Mongoloid types in Island Southeast Asia might have a bearing on the date of such a presence. There may not be a single date at all, if the transition to Southern Mongoloid was a gradual local evolutionary process. This could be a problem for the orthodox view of a late Mongoloid replacement. While this does not prove that Mongoloid features appeared in Island Southeast Asia at the time of the LGM, it does suggest they may have reached Java well before the Neolithic period, which is normally put forward as the date of their arrival. In summary, from both physical as well as genetic evidence, Aboriginal Malays may turn out to be descendants of the earliest Southern Mongoloids, as their original name, ‘Proto-Malays’, was intended to imply.30

  Mongoloid replacement in China?

  Turning now to the north, a similar picture of post-glacial, local genetic expansion clusters of mitochondrial DNA may be seen along the Pacific coastline from South China up to North Asia, reflecting refugee flow east from the Central Asian plain and subsequent expansion along the coast. Of these genetic expansions, the closest to the LGM is part of the common Asian Haplogroup D, with an age of 16,800 years. One D subgroup characteristic of the Chukchi aboriginals of the far north-east of Siberia is dated to 14,900 years ago. Others include A2 (11,200 years) and a C type (10,800 years).31

  In China and on the Pacific coast we find again relict aboriginal coastal groups from before the arrival of the Mongoloids, isolated this time not by jungle but by the sea. One of these groups is the well-known Ainu of northern Japan. The Ainu are descended from the original Jomon peoples of Japan, who 12,500 years ago made some of the world’s first pots. Later Mongoloid immigration from the mainland by the Yayoi of Korea all but replaced the original population, and the modern Ainu represent varying degrees of admixture. There are sufficient similarities between the prehistoric Jomon skulls, the ice-age Japanese Minatogawa 1 skull from Okinawa (dated to between 16,600 and 18,250 years ago; see Plate 20), and the modern Ainu for them to be regarded as lying on the same continuous line of descent. As mentioned above, these Pacific Rim groups may represent a pre-Mongoloid substratum.32

  As a result of its isolation, Japan probably received its last Mongoloid immigrants, the Yayoi, starting 2,300 years ago. This event is thought to have left its genetic trace. Studies conducted in different parts of Japan suggest that the YAP+ marker, Abel, one of the oldest out-of-Africa beachcombing lines, would have characterized the Jomons. In Okinawa, the rare Asian YAP+ marker achieves frequencies of 55 per cent. The other beachcombing Y marker, Cain, is also found among Japanese at rates of up to 10 per cent.33

  The Minatogawa 1 skull shows similarities with two other famous ancient skulls of China, the Upper Cave 101 and Liujiang (see Plate 19). The former is from the Zhoukoudian or Dragon Bone Hill in northern China and although poorly dated is certainly more than 10,000 years old and probably preglacial. The Liujiang skull is from southern China (see Chapter 4). Australian physical anthropologist Peter Brown has argued against the view that these three rather robust skulls show proto-Mongoloid features. On his plots they are closer to Australian aboriginals than to modern East Asians, although they are not even particularly close to the former.34

  This evidence is consistent with the idea that the preglacial population of China and the Pacific coast may still have resembled the first beachcombing settlers, before the Mongoloid expansions took place, and that their genetic heritage may still persist. The other ancient beachcombing Y marker, Cain, is also found in Northeast Asia, but this time on the mainland and coast in peoples of the Amur River, Okhotsk, Mongolia, and central and southern Siberia (see Figure 6.4). In these regions Cain, normally only present as a tiny minority, is found at rates of 50–90 per cent.35 The fact that this ancient Northeast Asian beachcombing marker persists is entirely consistent with the evidence from the skulls, which suggests that the ancestral non-Mongoloid population survived in that region until at least the LGM.

  Cultural evidence for an Asian dispersal

  Is there any archaeological evidence, apart from the Wajak skulls, to support the presence of antique Palaeolithic societies throughout North and East Asia who were infiltrated, or replaced by, Mongoloid dispersals from the Central Asian Steppe 20,000 years ago? There is, but with caveats. The interpretation of the archaeological record from Northeast Asia, China, and Korea (and also Southeast Asia) between 5,500 and 25,000 years ago is hampered by lack of coastal archaeological evidence. This is because today’s high sea level now covers the coastal sites that would have preferentially been occupied by the invaders (see above and Figure 6.3). What is left is a number of inland and island cave sites that could easily have been the refuges of the original indigenous peoples rather than those of the invaders.

  At this stage I would like to present a highly simplified interpretation of East Asian archaeology of the glacial period. This will serve as a background against which changes from the LGM onwards can be viewed. As we have seen (Chapter 3), Europe underwent a replacement of the Middle Palaeolithic technology of the Neanderthals by the more sophisticated Upper Palaeolithic technology of the first Anatomically Modern Humans there. We also saw that the Middle Palaeolithic technology of the Neanderthals was by no means primitive, but represented a tradition parallel to styles of Middle Stone Age tool-making by Anatomically Modern Humans in Africa before 50,000 years ago.

  It is therefore a surprise to find a low level of stone technology being used by modern humans in East and Southeast Asia at the time of the Neanderthals’ final competition with Cro-Magnons. Tools associated with Anatomically Modern Humans in Southeast Asia and Australia seem to have been less sophisticated than those used by the Neanderthals.36 The contrast is so great that in some cases archaeologists who have concentrated on the African and European Palaeolithic traditions cannot believe that some of the tools attributed to modern humans by their Asianist colleagues were artefacts at all.

  This contrast of styles and ‘quality’ was first pointed out by an American archaeologist, Hallam Movius, in 1948. What became known as the Movius Line separated off the Far East, including Southeast Asia, from the rest of the world as an area of cultural ‘backwardness’ and ‘unstandardized tools’ more or less right up to the last ice age. To make things even more confusing, the East Asian Palaeolithic tool-making tradition which produced what are called ‘chopper-chopping’ tools stretches from the time of modern human occupation back into the Middle Palaeolithic period, at least a million years ago. This was a time when East Asia was occupied by Homo erectus, and long before modern humans had even evolved. There is some dispute about when chopper-chopping tools were first made in Island Southeast Asia, with several archaeologists claiming, with reason, that they were first introduced by modern humans possibly around 70,000 years ago (see Chapter 4).37

  Several archaeologists have pointed out that the lack of sophistication of the chopper-chopping tools reflects the poor knapping quality of the types of stone available, for example quartzite and basalt. It has been surmised that people then were making (as they still do today) much more sophisticated implements from perishable materials such as hardwood, bamboo, and plant fibres.38 The fact that people of Oceania m
anaged to colonize the Northern Solomon Islands by boat 30,000 years ago, and tens of thousands of years before evidence of European sailing, is ample evidence – if any were needed – of the level of early technical sophistication in the Far East.

  A tale of two rivers

  Whatever the reasons for the persistence of the distinctive chopper-chopping industries in the Far East, they do provide us with a simple background on which to record the intrusions of other cultures into China and Southeast Asia from Central Asia at the height of the last ice age. On top of this general background is a geographical and chronological structure that we might call ‘a tale of two rivers’. Northern Chinese Palaeolithic cultures are geographically clustered around the Yellow River and, well before the LGM, under the increasing influence of Upper Palaeolithic innovations from Central Asia. First flakes, then blades, and finally the characteristic bifacial points reminiscent of the Diuktai cultures of eastern Siberia during the LGM, could have moved to places as far east as Japan to replace the older tools and weapons. Southern China, on the other hand, dominated as it was by the Yangtzi River and shielded both geographically and environmentally from the cultural influences of the Central Asian steppe, seems to have had a separate and rather slower evolution.39