Out of Eden: The Peopling of the World (38 page)

When the sea returned like a huge tide after the ice had melted, however, much of the archaeological evidence of such coastal occupation would have been washed away. We would expect to see such ice-age archaeological evidence only in regions with a steep coastline and continental shelf, such as Japan, and some of the Indonesian islands. Remnants of preglacial beachcombing populations would also be found only in regions that have remained isolated by geography or rising sea levels, such as Japan.

I should stress that the Mongoloid dispersal view I am presenting
here differs from orthodox archaeological reconstruction not just in dates and timescale but also in the movements of people. Some prehistorians of the Southeast Asian region, such as Australian Peter Bellwood, favour a recent one-off Mongoloid replacement of older Australo-Melanesian hunter-gatherers in Island Southeast Asia by Taiwanese from farther north along the Pacific Rim. In this view, the Australo-Melanesian hunter-gatherers would have corresponded most closely to the Semang ‘Negritos’ (see
Chapter 5
). Bellwood argues, moreover, that the expanding population of Mongoloids were Neolithic rice farmers from southern China who arrived by sea via Taiwan and the Philippines only 4,000 years ago. I have presented the evidence against this theory elsewhere.
¹⁷

What I am saying is first that Mongoloid expansions and re-expansions in East and Southeast Asia
started earlier
, around the LGM at least 18,000 years ago. They mainly used land routes, and have continued on and off ever since. In fact, possibly the largest population expansion in Island Southeast Asia before the present era may have occurred as recently as the arrival of the Metal Age in the islands, around the last few centuries BC, when rice agriculture greatly expanded.
¹⁸

The second point is that there were not just two groups, the Mongoloids migrating down from the north and the Semang-like hunter-gatherers, who were vying for the landmass of Southeast Asia. There was another indigenous expanding group, the Southern Mongoloids, who may have occupied the Southeast Asian continental shelf and much of the Pacific coastline from very ancient times, and may indeed have been ancestral to all Mongoloids themselves.

This indigenous Southern Mongoloid group is identified best by its unique and associated southern genetic markers, which dominate the region.
¹⁹
They probably looked rather like some minorities of south-eastern Indo-China today, and in particular like one of the groups of Malaysian aboriginals farther south in the Malay Peninsula, known as the Aboriginal Malays. The latter also resemble the
majority Malay population in having some Mongoloid features. From this perspective, aspects of the so-called Southern Mongoloid appearance may have been around for a much longer time. As we shall see, their ancestors can be identified by more than just their genes and teeth.

In common with the great majority of other Southeast Asians, the Aboriginal Malays have been identified as Sundadonts. The Aboriginal Malays are even closer dentally to the Pacific Rim populations, including the Polynesians, and on a dental basis could be regarded as ancestral to the Sinodonts further north (see
Chapter 5
and
Figures 5.3
and
5.4
).
²⁰
In short, Southern Mongoloids could have been around in the South since before the LGM.

Post-glacial Asian invasions of Southeast Asia and Oceania

As I have said, my reconstruction is based more on the genetic record than on the scanty skeletal and archaeological record. In fact, my own interest in genetic prehistory was first awakened by medical genetics, while I was working in the south-west Pacific in the early 1980s. My findings suggested that
early
migrations of local genetic types out of Southeast Asia to New Guinea and Island Melanesia were more likely than huge
late
Mongoloid migrations from China replacing Australo-Melanesians throughout Australasia and the Pacific, as previously thought.
²¹
So I shall start with genetic evidence for the dates of Mongoloid expansions into Southeast Asia and Oceania.

In
Chapter 3
we saw how the some of the best combinations of archaeological, physical, and genetic evidence for the early route out-of-Africa come from intermediate and end points of the trail in Malaysia, Australia, and New Guinea. I also described how the deep branching genetic lines for the Australia and New Guinea were different from each other, indicating the antiquity of their colonization. The unique genetic identity of such early arrivals allows us to measure and clearly identify all latecomers and to see where they
came from. Equally useful is the ability to date and estimate the size of later migrations.

By taking this approach, the English geneticist Martin Richards and I were able to suggest that while, in agreement with current views, the ancestors of the Polynesians – the great Pacific pioneers of 3,500 years ago – were mostly different from the oldest inhabitants of the New Guinea region, they did not come from Taiwan, farther north, as generally believed but from Southeast Asia. Furthermore, although the Polynesian lines were newcomers to the Pacific, their own forebears had probably already arrived in eastern Indonesia from Indo-China by 17,000 years ago.
²²
The lines carried by the Polynesians were branches of those found on the Southeast Asian mainland, and one ancient line in particular (mtDNA Haplogroup B4) was shared with the American dispersal via the northern Pacific Rim. Apart from genetically linking the Americans with the Southeast Asian dispersals, this also suggests a date near the LGM for the earliest migrations out of mainland Southeast Asia. Richards and I have continued to explore other markers of Southeast Asian migration, leading up to the work on the aboriginal peoples of the Malay Peninsula described in this book.

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