Out of Eden: The Peopling of the World (24 page)

Europe’s Asian roots

This trip through genetic and human time has suggested two extraordinary conclusions: first, that the Europeans’ genetic homeland was originally in South Asia in the Pakistan/Gulf region over 50,000 years ago; and second, that the Europeans’ ancestors followed at least two widely separated routes to arrive, ultimately, in the same cold but rich garden. The earliest of these routes was the Fertile Crescent, which opened 51,000 years ago as a corridor from
the Gulf, allowing movement up through Turkey and eventually to Bulgaria and Southern Europe. This seems to coincide with the Aurignacian cultural movement into Europe. The second early route from South Asia to Europe may have been up the Indus into Kashmir and on to Central Asia, where perhaps more than 40,000 years ago hunters first started bringing down game as large as mammoths. Some of these hunters with their elaborate technical skills may then have moved westward across the Urals to European Russia and on to the Czech Republic and Germany. A more conservative view of this eastern invasion might be that the Trans-Caucasus, rather than Central Asia, was the earliest route of modern human entry into Russia.

F
IRST STEPS INTO
A
SIA, FIRST LEAP TO
A
USTRALIA

I
N
CHAPTER
1
WE SAW EVIDENCE
for a single out-of-Africa genetic line, L3, whose two daughter lines, Manju and Nasreen, jointly peopled the rest of the world. This single genetic line is central to the logic of a single southern exodus. As we saw in
Chapter 3
, the fact that, uniquely, Europeans are descended solely from the Nasreen clan fixes the origin of their branch to a colony early on the route out of Africa, probably near the Gulf. The absence of any of the root daughter genetic branches of either Manju or Nasreen in North Africa or the Levant, and their abundance in India, excludes the northern route into Europe and confirms the southern route across the mouth of the Red Sea. We shall now look in more detail at the genetic and other evidence for the earliest primary colonization of South Asia and the coastline of the Indian Ocean beyond. The Y chromosome now enters the story more fully, along with some genetic markers other than the Adam and Eve genes. South Asia includes all the countries initially found along that pioneering beachcombing trail round the northern shores of the Indian Ocean.

Survivors of the great trek: place and time

If all non-Africans share one ancestral origin, the date of exit for the ancestors of aboriginal Australians is the same as for Europeans, Indians, and Chinese. All their trails should lead back to one point in space and time; and all the colonies, left behind en route, should hold genetic and even physical keys to who went that way. This is the case. We can look at the mtDNA or Y chromosomes from anyone outside Africa, and find them a place on their respective single branch of the out-of-Africa genetic tree. Exactly where they are on their out-of-Africa branch very often tells us how they got there and even, sometimes, when.

We should not be tempted into trying to draw firm conclusions from genetic dates in isolation. The exact branching
structure
of the tree and the geographical distribution of the branches are often much more revealing than are dates for them derived from the molecular clock.
¹
Those dates are rather approximate and should always be weighed against of the rest of the evidence, namely the climatic record, which tells us when there were windows of opportunity for or constraints against migration, and of course the archaeological record, where present.

The archaeological beach trail is inevitably very faint. Between 60,000 and 85,000 years ago the sea level fluctuated between 40 and 100 metres (130 and 330 feet) below its present level, so the beaches and even the hinterlands our ancestors wandered along and frequented are now mostly deeply submerged. But there are exceptions to the effects of this watery blanket, as we shall see.

Along the coastline of the Indian Ocean we still find small colonies of so-called aboriginal peoples who may be descended locally from those first beachcombers. Long before the study of mtDNA, the first reasons for calling these groups aboriginals were that their cultures and appearance marked them out from the people surrounding them: some had features in common with Africans, such as
frizzy hair and very dark skin. I shall discuss the more objective genetic and physical evidence to support these impressions here and in the next chapter, but it is worth first naming some of the groups in question.

Such peoples are often called by controversial and presumptive terms such as ‘Australoid’, ‘Negroid’, and ‘Negrito’ to indicate how they differ from surrounding peoples. Starting from the South Arabian coast in the west there are the Hadramaut, who have been described as Australoid but almost certainly contain an element of much more recent African admixture. On the coast of Pakistan around the mouth of the Indus are found the Makrani Negroid ethnic groups. Again, there is genetic and historical evidence to support a major recent African admixture as a result of the slave trade. This may not be the case for other so-called Negroid types, such as are found in India, including the Kadar and Paniyan. There are also a number of other South Asian aboriginal groups including the so-called Proto-Australoid ethnic groups, such as the Korava, Yanadi, Irula, Gadaba, and Chenchu of India, and the Veddas of Sri Lanka. Recent work on two of these groups, the Chenchus and Koyas, has strongly suggested not only that their ancestral mtDNA and Y chromosomes were uniquely shared with other South and West Asians, but that they are characteristic of the earliest genetic heritage of the region. Their beach-settling ancestors from Africa would have provided the genetic seeds for the subsequent differentiation of the distinctive East and West Eurasian gene pools, and they would have received only limited gene flow from other regions since then.
²

The Andaman Islands, situated between India and Southeast Asia in the Bay of Bengal, include several groups with preliterate traditional cultures and a very distinctive, so-called African appearance. The groups least affected by outside intrusions are the Jarawa and the Onge, who live in the most southerly Andamans. Recent genetic studies still being analysed may help to elucidate their maternal and paternal origins. On the maternal side, the Onge and Jarawa feature
two distinct mitochondrial groups which nevertheless both place them in the Manju super-clan, thus confirming fellowship of the single out-of-Africa migration. These genetic lines show connections to the base of two ancient and unique Indian Manju clans, M2 and M4. M2 is the oldest and most diverse Indian Manju group and is also the commonest mtDNA component among the Indian aboriginal groups mentioned above. On the paternal side, the Onge and Jarawa possess only the Abel clan (the rarest of the three out-of-Africa Y lines, and known as Group D or Asian YAP). This is all consistent with the view that the Onge and Jarawa have remained as isolated groups since the early beachcombing sweep round the Indian Ocean. The other aboriginal groups in these islands, known as the Greater Andamanese, are slightly different culturally and physically. Genetically, while they share branches of the same two unique Manju genetic lines, significantly their Y chromosomes all come from another of the three sons of Out-of-Africa Adam, Seth (see
Figures 4.2
–
4.4
).
³

Farther along the trail are the so-called Negrito peoples of the Malay Peninsula, known generally as the Semang (see
Plate 16
), and perhaps the best known of the candidate remnants of the old beachcombers. Another relict group possibly left over from the beachcombers in Indo-China and the Malay Peninsula are the so-called Aboriginal Malays, who are physically intermediate between the Semang and Mongoloid populations (see
Chapter 5
). Crucially, they hold clues to the earliest branches of an mtDNA line now characteristic of Mongoloid populations, known as the F clan. This founder East Asian maternal pre-F line in Malay aboriginals is also shared with groups across the water in the Greater Andamans, discussed above, as well as with people in the Nicobar Islands a little farther south.
⁴

I shall have more to say, in this and the next chapter, about the various peoples and colonies thought to be left over from that first great trek along the coastline of the Indian Ocean. As always, what is
most important to bear in mind is that the genetic tree tells us this was not an earlier out-of-Africa venture, as has been thought by some archaeologists and palaeontologists. It was the vanguard of colonization of the entire Old World.

Curiously, some of the best, if not the only archaeological evidence for dating the beachcombers’ trek along the coast of the Indian Ocean comes not from India, South Arabia, or Africa, but from the later parts of the trail – the Malay Peninsula, New Guinea, and Australia. So we shall take a trip there first to look at those who travelled farthest round the Indian Ocean, the New Guineans and the Australians.

The first Australians

Perhaps more academic heat has been generated over
which
humans first got to Australia, and
when
, than over any other question on the archaeology of the region. The ‘which?’ question, a rallying call for multiregionalists with their repetitive arguments about different regional skull shapes derived from earlier humans (see
Chapter 1
), is looking less and less relevant in the face of increasing genetic evidence that all modern Australians and New Guineans belong to either the Nasreen or the Manju clan.
⁵
In other words, they are not a special case, nor are they an earlier type of human or modern humans mixed with local
Homo erectus
. The mounting evidence has not stopped rearguard, Spielberg-like attempts by multiregionalists to use extremely ancient DNA to resuscitate their case. However, the evidence now available comes down on the side of antipodeans belonging to the same single out-of-Africa L3 migration as everyone else (for a discussion of recent developments on this thorny issue, see note
⁶
). The ‘when?’ question is now coming much more to the fore. Historians like to peg events on dates rather than be satisfied with a simple chronological order, so I shall deal with dates first, although they will probably be the last issue to be finally resolved.

The earliest generally accepted archaeological evidence of modern human colonization outside Africa has, until recently, been Australian – but this is a rapidly changing field. Until the 1990s, there was no clear evidence for humans in Australia or New Guinea before 40,000 years ago. It now seems that, as with datings for Europe, this was largely due to the limitations of the radiocarbon method of dating. But then new methods of dating began to be applied. One approach, the so-called luminescence dating of silica, enabled researchers to probe beyond the radiocarbon limit of 40,000 years. In 1990, the Australian geologist-cum-archaeologist team of Richard Roberts and Rhys Jones reported dates between 50,000 and 60,000 years ago for the first occupation of a rock shelter (see
Figure 4.1
) on the coast of Arnhem Land, in northern Australia. Arnhem Land is directly opposite Timor, the nearest island of the Indonesian archipelago and therefore the most likely casting-off point for the first Australians.
⁷

Then Australian ‘dates’ took a rather more dramatic turn and, as it were, came off the wall. In 1996, archaeologist Robert Fullagar examined the rock art site of Jinmium. The wall of this shelter is covered in artefactual dents known as pecked cupules, and Fullagar reported that a fallen fragment of engraved sandstone, buried in sediments, had been dated in two independent estimates to 50,000 and 75,300 years ago. He even recovered stone artefacts from levels dated by thermoluminescence to between 116,000 and 176,000 years ago, which would have made it the oldest known human occupation site on the continent, and two to three times as old as the Arnhem Land shelters mentioned above. These new dates caused a furore. But the problem appeared to be solved when it was shown that contamination by sand grains from fallen rubble had produced the wildly old dates for the earth surrounding the artefacts. In other words, the dates were wrong, and analysis of individual grains of sand helped to detect and overcome inaccuracies
caused by contamination. The oldest dates of human occupation in Australia have therefore remained around 60,000 years.
⁸

Controversially, human occupation dates as old as 62,000 years ago were also recently published, based on several different methods applied to earth surrounding the skeleton of a gracile Anatomically Modern Human found at Lake Mungo in the Willandra Lakes region of south-east Australia. One of these reports pointed out that, to have been there so long ago, the first Australians must have crossed earlier at a previous low sea level. The low-sea window of opportunity to get to Australia 70,000 to 60,000 years ago suggests that the anatomically modern Lake Mungo people really were among the oldest on that continent, since the previous low sea level was another 80,000 years before, and near the dawn of our species.
⁹

Only one window of opportunity

Whatever the academic claims and counter-claims, there seems now to be a convergence of evidence from a variety of sites that points to a human presence in Australia as far back as 60,000 years ago. This date followed a very deep lowstand of the world’s oceans caused by an increase in water locked up in the northern ice caps, and took Australia’s shores to around 100 metres (330 feet) vertically below today’s levels. Although the date of lowest sea level of that glacial period was 65,000 years ago, the world’s oceans only fell below 100 metres briefly at that point, and then rose rather rapidly.
¹⁰