Out of Eden: The Peopling of the World

by Oppenheimer, Stephen

  The day after our arrival, we went down the cliff to the dry estuarine plain and found some friendly Afars watering their herds. To preserve the natural well, they drew up water in buckets and deposited it in large, dish-like mud basins they had built into the sand. While the cattle, goats, and sheep waited in single file for their turn to drink from these improvised troughs, the herders chanted a water-song.

  Immediately above this ancient scene, Seife Berhe showed me the 125,000-year-old shell middens, the remains of meals of oysters looking as if they had been left behind only yesterday. Clearly visible, sticking out from but cemented in among the fossilized shells of the midden was an obsidian flake tool. From its shape it had clearly been worked, but it must have been brought to the reef because the nearest source of obsidian is 20 km (12 miles) away. The shell midden, butchered animal bones, the flake, and other obsidian artefacts completed the picture of a mixed diet eaten by the humans who lived by this reef so long ago.

  Pieces of coral block were in the process of breaking away from the cliff, otherwise we would not have been able to climb and squeeze in so close. In the coral debris in the sand around these great blocks of coral were numerous small obsidian bladelets, 10–40 mm (0.4–1.6 inches) long, some very bright and sharp. I could have shaved myself with them. I remembered that the Nature paper reporting this important archaeological site had told of obsidian blades in the reef, but these were microliths. The puzzle was that 125,000 years ago should have been much too early for such small tools, unless they had been put there much later. The fact that they were loose, showing no clear association with the midden, made this an alternative possibility. Microliths start appearing in the African archaeological record only from 80,000 years ago. They were present all over the sand above the cliff, so maybe that was the case. Interestingly, the earliest microliths outside Africa have all been found to the east of the Red Sea in Sri Lanka.35

  Last among the key elements of the ‘modern human’ behaviour package we find long-distance exchange – in other words, some form of trading or movement of important objects such as tools and raw obsidian over distances up to 300 km (200 miles). Again, we see in the African record that this most human of behaviours started at least 140,000 years ago.36

  Two million years of human know-how

  McBrearty and Brooks’ composite picture of the first ‘Anatomically Modern’ Africans shows that soon after their first appearance, by around 140,000 years ago, half of the fourteen important clues to cognitive skills and behaviour which underpinned those that eventually took us to the Moon were already present. Three of these (pigment processing, grindstones, and blades) had been invented by the previous species of modern humans 140,000 years before that. By 100,000 years ago – just after the first exodus to the Levant – three-quarters of these skills had been invented; and the remaining three were in place before the first moderns stepped into Europe (see Figure 2.5). With such a perspective of cumulative increments in culture over the past 300,000 years, the concept of a sudden modern ‘European Human Revolution’ 40,000 years ago pops like a bubble. We begin to see instead our essential humanness as ‘adaptation and invention followed by physical evolution’ stretching right back into the 2-million-year story of our genus Homo – hunters, inventors, and tool-makers from the start.

  In spite of this deconstruction of its evolutionary importance, the European Upper Palaeolithic remains a unique record of a most glorious period of local self-discovery. But what does it tell us about ourselves? Well, there are some hints, from the distribution and dates of the earliest Upper Palaeolithic stone cultures that were clearly associated with modern humans’ invasion of Europe – the Aurignacian and its successor, the Gravettian – that there was not one invasion, but two. In the next chapter we shall find out why, where from, and how the genetic trail reinforces this view.

  3

  TWO KINDS OF EUROPEAN

  AS WE HAVE SEEN, the teasing issue of European origins is not just a matter of whether the future Europeans migrated out of Africa separately from the future Asians and Australians, or of just burying the myth that they were the first humans to show modern behaviour. It is more than that. Where did their extraordinary flowering of culture originate? Was it entirely home-grown, or was it imported? Why do some archaeologists argue for several different early cultural inputs to Europe in the period between 20,000 and 50,000 years ago – even one from the East? In this chapter we shall see that there are precise male and female genetic markers which parallel two different cultural waves that flowed in succession over the European archaeological record of the 25,000 years leading up the Last Glacial Maximum. These reveal that an ‘Eastern’ origin was no wild guess.

  In Chapter 1 we saw that the ancestors of Europeans, the N (or Nasreen) clan, belonged to one of the first branches off the single exodus shoot which arrived in southern Arabia perhaps 80,000 years ago. In spite of this secure position at the root of the Asian maternal genetic tree, the Europeans’ ancestors had to wait tens of thousands of years in South Asia. They waited until after 50,000 years ago, when a moist, warm phase greened the Arabian Desert sufficiently to open the Fertile Crescent and allowed them to migrate north-westwards towards Turkey and the Levant. Such constraints had not affected their cousins – the vanguard of beachcombers who pressed on round the Indian Ocean coast to Southeast Asia and Australia. They arrived in Australia over 60,000 years ago, long before Europe was colonized.

  From an Asian point of view, Europe is an inaccessible peninsula jutting out north-west from the Old World, a geographical cul-de-sac. Genetically as well as geographically, Europeans are, similarly, a side-branch of the out-of-Africa human tree. Because the first non-African modern humans were Asians, ‘peninsular Europe’ was more likely to have been a recipient and beneficiary of the seeds of the earliest Upper Palaeolithic cultural innovations rather than their homeland. From this perspective the last chapter was devoted to deconstructing the archaeological/anthropological myth of a major human biological revolution defined in Europe and the Levant, with everyone else in the world following the European lead.

  The first modern Europeans

  We saw in the last chapter that our cousins the Neanderthals had already started to learn the smart new Upper Palaeolithic technology before their demise around 28,000 years ago. This partial blurring of the cultural distinction between Neanderthals and modern humans does not mean that archaeologists cannot detect the very clear cultural trails that mark the movement of the earliest modern humans into Europe. On the contrary, starting before 30,000 years ago, several such cultural traditions, specifically associated with modern humans, spread rapidly and successively across Europe. The dates and directions of spread of these traditions were different, and they have been given a number of names, based on the styles of tools and where the tools were found. The nature of the early modern cultures in Europe was diverse, and some archaeologists classify them more broadly into two waves. The concept of movement can be taken even further than cultural diffusion to suggest two different human migrations with their associated cultures. The first of these waves, which commenced as early as 46,000 years ago, is called the Aurignacian, after the village of Aurignac (Haute-Garonne) in southern France, where typical artefacts were initially found. The later one, mainly from 21,000–30,000 years ago, is called the Gravettian after the French site of La Gravette in the Perigord region, and is characterized by backed blades (where one edge is blunted, like a penknife) and pointed blades.1

  It is tempting to attribute the spreading of ideas to mass migrations of people. However, as more recent history shows us, the movement of ideas and skills through populations can be more rapid and comprehensive than the movement of the people themselves. But for the first modern human colonizations of Europe there really does seem to be genetic evidence for at least two separate migrations corresponding to the new cultural traditions brought in by the moderns.

  The Aurignacians

  The Aurignacian Upper Palaeolith
ic culture first appeared in Europe in Bulgaria, presumably arriving from Turkey, after 50,000 years ago. Fairly soon after this, the new style of stone tools moved up the Danube to Istállósko in Hungary and then across, still westward along the Danube, to Willendorf, in Austria. The apparently relentless movement of Aurignacian culture, upriver and west from the Black Sea, eventually brought it to the upper reaches of the Danube at Geissenklösterle, Germany. Long before this time, however, the Aurignacian culture had also moved south from Austria into northern Italy. From there it spread rapidly, westward along the Riviera, across the Pyrenees, and through El Castillo in northern Spain, before finally reaching the Portuguese Atlantic coast by 38,000 years ago.2 (Figure 3.1)

  Figure 3.1 Map of the suggested routes of spread of Aurignacian pioneers into Europe before 37,000 years ago. Only the earliest Aurignacian sites are shown (filled dots) – the dashed line represents natural routes along rivers, lowland and coast joining the dots. A parallel route from the Zagros to Karabom in the Russian Altai is shown.

  The Aurignacian cultural tradition persisted in some form or another until much later and in due course became more unequivocally identified with modern human skeletal remains; but this early, rapid spread into regions which had previously hosted only Middle Palaeolithic cultures suggests a real colonization event. There is no clearly dated archaeological source for the Aurignacian tool styles outside Europe from earlier than 47,000 years ago, but the Near East is a strong candidate. Belgian archaeologist Marcel Otte has suggested the Zagros Mountains (part of the Fertile Crescent) as a core homeland for the Aurignacian stone-crafting techniques, which is consistent with my view of the Fertile Crescent as a Palaeolithic corridor into the Levant. The route of entry of the first modern humans into Europe was most likely via the Bosporus (which at that time was dry, with the Black Sea a freshwater lake).3

  Matching genes to the dates on the stones

  The tantalizing question is whether there are any genetic traces of this first entry into Europe. Astoundingly, there is in fact just one single mitochondrial line that has anything like that antiquity in Europe, and ‘she’ has an ancestor in the Near East. In other words, there is a fit, and most likely indicates that Europe was initially colonized by a single group. This insight does not come from opening a ‘genetic history book’ and looking for the right gene line with the right date – such books do not exist.4 The tangled genetic prehistory of Europe is only just beginning to be teased apart. For a start, in the past 50,000 years Europe has seen multiple population movements and suffered massive extinctions in the ice age. Wars, invasions, and later migrations to and fro between Europe and the Near East may have churned the human melting pot on several occasions.

  A major international team of thirty-seven collaborators, headed by evolutionary geneticist Martin Richards, now of Huddersfield University, England, collected all available mtDNA data and recently showed us how it can be done. They reviewed nearly all existing prehistoric mitochondrial research on Europe, and using a carefully crafted set of rules to detect and eliminate errors, such as effects of back-migration, they identified eleven founder lines in Europe and eighteen potential source lines in the Near East.5

  Using the genetic clock, Richards and his colleagues dated both the source lines in the Near East and the founder lines in Europe (Figure 3.2). Four of the source lines (J, T, U5, and I in the figure) in the Levant could be dated to between 45,000 and 55,000 years ago, suggesting that the Near East had itself been colonized around that time by lines that were daughters and granddaughters of Nasreen. As can be seen from Figure 3.3, these were of course great-granddaughter and granddaughter lines from L3, our single Out-of-Africa Eve. Given the quite wide error margins for mtDNA dates, 45,000–55,000 years ago still brackets the earliest Upper Palaeolithic dates, so the time of the colonization of the Near East seems to fit.6

  The fifth daughter of Europa

  Perhaps the most stunning conclusion of many reached in this comprehensive review of European maternal genetic prehistory is the identification and dating of Europe’s first founder line, U5. Initially it was only U5, a genetic great-granddaughter of one of the four main Levantine founders, who moved into Europe (Figure 3.4). The Europa clan is characteristic of the Near East and Europe. In spite of its antiquity, it is not found in East Asia, being confined to the Levant and the Gulf, western Central Asia, countries round the Mediterranean, and Europe, with an ancient daughter branch, U2i, in India. The clan as a whole has an antiquity of over 50,000 years in the Near East. According to the molecular clock, our fifth daughter of Europa, U5, also dates back 50,000 years and represents by far the earliest line to enter Europe, 15,000 years before the next European founder line. But how is it that Europa’s genetic signal spread to the Near East and, through her daughter U5, on to Europe, from 54,400 to 50,000 years ago, when the archaeological dates for the Upper Palaeolithic first appearing in the Levant, and then the earliest Aurignacian in Bulgaria, are respectively only 47,100 and 46,000 years? This difference can be explained by a systematic under-recording of radiocarbon dates for any age over 40,000 years, giving a ceiling effect.7

  Figure 3.2 Estimated dates of intrusion (95% confidence range) of modern human mtDNA lines into Europe from the Near East, using founder analysis.5 The earliest line is from Europa (U5), corresponding with the Earliest Upper Palaeolithic in Europe, followed by ‘HV’ corresponding with the Early Upper Palaeolithic, and ‘I’ corresponding with the Middle Upper Palaeolithic.1

  Figure 3.3 The West Eurasian mtDNA tree. As can be seen, Manju does not feature and, although Nasreen and Rohani date to between 65–70,000 years, expansion of West Eurasian lines only occurs after 55,000 years ago, corresponding with north-west movement from South Asia. Links with India10, North Africa9 and America (see Chapter 747) in paler shade. Dating based on complete mtDNA sequence analysis (see Chapter 122).

  Although U5 apparently had her origins in the Near East at roughly the same time as her entry into Europe, her descendants are found there now only in a restricted area in minorities living mainly in Turkey and the Trans-Caucasus region of Turkey and Iran (see Figure 3.4). These minorities include the Turks, Armenians, Azerbaijanis, and Kurds, all of whom still live within the ancient limits of the Fertile Crescent that stretches from Turkey and the Trans-Caucasus south-east along the Zagros Mountains through Iraq and Iran. The Fertile Crescent co-extends with Kurdistan, finally forming a corridor parallel to but north of Mesopotamia, running towards the coast of the Arabian Gulf and thus linking the Levant with the Indian Ocean. Significantly, U5 is almost absent from Arabia, apparently denying those peoples’ ancestors as the primary source population for the first Aurignacian colonization of Europe.

  Figure 3.4 Suggested routes of spread of gene lines into Europe. Grey line corresponds with the Earliest Upper Palaeolithic, remaining concentrated round the Mediterranean (Figure 3.1), black line with the later ‘Early Upper Palaeolithic’ entering from Eastern Europe and found more in north and western Europe.3,5,8,14–19,28–37 (Y-chromosome lines are in italic – less securely dated than mtDNA.29)

  Do we have any genetic trail that exactly fits the rapid movement of the Aurignacian tool-makers, westward within central Europe, taking them to the Pyrenees and Spain by 40,000 years ago? Although U5 is now ubiquitous in Europe, we do know that the oldest Europa great-granddaughter, U5a, dating from around 40,000 years ago, is commonest in the Basque country of northern Spain. One of the only European refuges during the last ice age, the Basque region managed to preserve more of its original genetic diversity than did other parts of Western Europe.

  U5 is thus the one surviving Europa daughter line that identifies the first European ancestors up to 50,000 years ago, and is an ancestral type shared with Armenians, Turks, Azeris, and Kurds. What do we know of her family, where did she come from, and who were her sisters? Inspection of the gene-line tree (see Figure 3.3) gives us a genealogy that we can recount in biblical style: Europa was genetic daughter of Rohani, w
ho was genetic daughter of Nasreen, who was the genetic daughter of the out-of-Africa L3. By what route, however, did the Europa maternal clan arrive in the Levant, and where was her daughter U5, who colonized Europe, born? Both the Nasreen and Rohani root types are unknown except in South Asia, where Nasreen root types are found at low rates and Rohani is found in great variety. Most Rohani types in India are found nowhere else, and the great diversity of Rohani in India allows us to estimate when her line began to expand. This was at least 55,000 years ago, thus predating the arrival of Rohani’s daughter Europa in the Levant and making a strong case for South Asia as the ultimate ancestral home of European lines. Even this expansion date is likely to be an underestimate of the age of the Rohani clan. Rohani may well be older than 55,000 years in Asia: much older estimates of the ages of two Asian subgroups of Rohani have been obtained in China.8

  The first three of the seven Europa daughters were all 50,000 years old

  The fifth genetic daughter of the Europa clan did have other sisters: there were seven Europa daughters, but only two of them were anything like the same age as U5. These were U6 and U2i, and neither was characteristic of Europeans. We have already come across U6 in North Africa. A unique identifier of Berbers, she has the same age as U5, 50,000 years, suggesting that as U5 moved north-west out of Turkey into Europe, U6 moved west round the southern shore of the Mediterranean to North Africa. We even have possible physical evidence of those North African pioneers arriving from the Levant. Early Upper Palaeolithic tools have been found at the Libyan coastal site of Haua Fteah probably starting from 40,000 years ago, and possibly reflecting this early invasion.9