Out of Eden: The Peopling of the World

by Oppenheimer, Stephen

  The third of the Europa clan’s three 50,000-year-old genetic daughters seems to have been born a quarter of the globe away from the Berbers of Libya, somewhere along the coast of the Indian Ocean. Accounting for 9.5 per cent of all Indian maternal lines and a massive 78 per cent of all Indian Europa lines, U2i is clearly home-grown in that region, with an age of 53,000 years in India. U2i is absent from the Levant and Europe, where we find a small European branch version, U2e, at half to two-thirds of her age.10 (See Figure 3.3.)

  Another pointer to the South Asian region as the ancestral source of the Europa clan is the finding of the ancestral root Europa type there and the origins of another Europa branch, U7, that subsequently spread in a small way to the Near East and Europe.11

  The Fertile Crescent corridor opens

  Our maternal gene tree thus suggests ultimately a 50,000-year-old South Asian origin for our oldest European founders. To arrive further north in Anatolia over 50,000 years ago they would have had to skirt the Libyan and Arabian Deserts, using the Fertile Crescent as a corridor. Given the rather generous margins of error on the molecular clock, for that trek up from the Zagros Mountains and Gulf marshes in south-west Iran, we should look at their migration from the perspective of climatic opportunity which, like the rings on a tree, gives us the most accurate dating. As I pointed out in Chapter 1, the Fertile Crescent corridor was dry, and was closed during much of the last 100,000 years, opening only briefly during climatic improvements called ‘interstadials’ (see Figure 1.7).

  Between 55,000 and 65,000 years ago the world went through a period of almost unremitting cold and dryness. During this time the Fertile Crescent corridor was shut. Then, from 56,000 years ago onwards, there followed in quick succession a run of four warm and wet periods. The last of these, 51,000 years ago, was the warmest and most prolonged, lasting nearly 5,000 years. In fact, so warm and wet was this interstadial that the Indian monsoon was even wetter than it is today, and so, apart from the opening of the Fertile Crescent corridor, dry areas of the Levant such as the Negev Desert became potentially habitable for our Upper Palaeolithic toolmakers. If there was ever a time for us to multiply in South Asia and spread up to the Levant, this was it. The climatic and archaeological clock timings converge on the lush period between 45,000 and 50,000 years ago. So it looks as though the molecular clock’s timing for the arrival of the earliest daughter lines of Nasreen and their families in the Levant is not far off.12

  Adam’s story

  So, we have the story of the female Europa clan originating somewhere in South Asia over 50,000 years ago. The complete absence of the dominant Indian Manju clan in Europe and the Levant suggests that Europa, by contrast, may have been born to the west of India, even at the base of the Fertile Crescent near the ancient city of Ur on the Arabian Gulf. But of course, where there are mothers so also are there fathers. In Chapter 1, I briefly described the single Out-of-Africa Adam line and his three sons, Cain, Abel, and Seth, who left Africa by the southern route to people the world. All three genetic sons came from that single exodus.13 Is there a similar story of the three sons of Out-of-Africa Adam, mirroring the tale of the two daughters of Out-of-Africa Eve in this particular trek from South Asia? Well, there is, and the geographical story of the descendants of at least one Y line, Seth, is even more specific than for the tale of Europa – although it is hard to date. (For another line, the Abel or YAP type, the argument may resolve one of the greatest puzzles in male genetic prehistory; see Chapter 4.) As with the story of Europa’s daughters, we need to trace back from the twigs down to the branches to know in which direction the menfolk moved.

  The descendants of Seth, son of Out-of-Africa Adam (Figure 3.5), are the most numerous in the world, let alone outside Africa. Along with Seth’s root type, one of his five sons dominates the Middle East, accounting for between a quarter and half of all males in the region between Iran and the Mediterranean. According to a recent consensus reclassification this son is known as J, but I shall call him Jahangir, to reflect his putative South Asian origin. In West and South Eurasia he follows the Europa clan’s distribution. The north-east coast of the Mediterranean Sea has the highest European rates of this genetic line. The Jahangir line reaches high frequencies in the Levant (30–60 per cent). The highest European frequency is in Anatolia, at 40 per cent, followed by the Balkans and Italy at 20–30 per cent. While Jahangir is found throughout Europe, such high frequencies are concentrated around the Mediterranean. There are also high frequencies in North African countries, such as 41 per cent in Algeria.14

  Figure 3.5 The West Eurasian Y-chromosome tree, geographical distribution and routes of entry. The tree is a subset of the eight main Y groups in West Eurasia (Consensus codes at end of each branch13). The table gives crude frequency of the same eight groups in three regions of Europe and four potential route locations en route from South Asia: e.g. Ruslan and M17 clearly enter through Eastern Europe, and high rates in Turkey and Mediterranean indicate southern entry to Europe – as shown in the map, where Jahangir has high rates and decreasing diversity from Pakistan to the Mediterranean.14–16,19,29–37

  Such a Mediterranean distribution mirrors the spread of U5 and U6 50,000 years ago, so it is tempting to look back further south and east for the origins of Jahangir. When we do, the trail down the Fertile Crescent through Kurdistan becomes hotter the further south-east we go. Mostly above 35 per cent throughout Iran, the Jahangir male clan reaches frequencies of 55 per cent in the southern Caspian region and 59 per cent in the Zagros Mountains region further south. Jahangir is also found further south still, in Pakistan and India, and also in Central Asia and Siberia, but at lower frequencies.15

  Clearly, frequency alone cannot tell us where a clan homeland is, but the diversity of genetic lines can help. Paris-based geneticist Lluís Quintana-Murci and colleagues argue for the ultimate origin of the Jahangir clan in the Zagros Mountains in south Kurdistan – the ancient land of Elam on the north-east bank of the Gulf. They have good reason, for the Zagros region has the greatest diversity of Jahangir types anywhere in the world. As I mentioned earlier, there is little agreement on calibration and methods of Y-chromosome dating, and most tend to underestimate dates; but one method gives an age for Jahangir of around 42,000 years in Europe, 55,000 years in Iran and 49,000 years farther south in India. Clearly these dates would be consistent with the maternal genetic story, but, as with other Y lines, some other methods give much younger estimates.16

  We have seen how the archaeological, climatic, and genetic stories of the first entry of modern humans into the Levant, and thence to both Europe and North Africa from around 50,000 years ago, can be drawn together. This South Asian origin for Europeans contrasts with the conventional view of a trail leading from North Africa round the Eastern Mediterranean into Europe, for which such combined evidence is scant.

  We can instead trace dates and locations up the Fertile Crescent along the flanks of the Zagros range from the Gulf. A climatic opportunity to migrate up the Fertile Crescent through Kurdistan was provided by a prolonged interstadial warm spell. There is archaeological evidence for a homeland of the Aurignacian culture in the Zagros Mountains. The earliest Aurignacians in Europe appear in Bulgaria, not far from the Bosporus, around 47,000 years ago. When we look for genetic equivalents for such a migration, we find an early colonization of the Near East by multiple maternal lines, originating in the South but now characteristic of West Eurasia, around 50,000 years ago. There is no ancestral genetic provenance for these lines in North Africa, so the evidence points logically to the South Asian exodus. Three daughter lines of the Europa clan appear, around the same time as the colonization of the Levant, respectively as founders to India, North Africa, and Europe. Finally, a supporting trail for the maternal lines can be seen in the male line Jahangir, who also originated in South Asia, although there is less agreement on the date.

  A second invasion of Europe: the Gravettian

  From the Middle-Eastern tangle of Nasreen’s
line, Martin Richards and his colleagues teased out a second European migrant thread, and another stunning but different story. They called this second clan migrating into Europe HV, after the two daughter branches, H and V, which are found throughout Europe today (see Figures 3.2, 3.3 and 3.4). The second daughter line, V, did not appear until much later, in south-west Europe. The H descendants were to provide half of all western and northern European maternal lines, Slav, Finn, and Germanic in particular. This is clearly different from the very early U5 story. The expansion of HV has been dated to around 33,500 years ago – over 15,000 years later than U5, and 7,500 years before the next entrant. What is really interesting is that HV is considerably younger in the Near East (26,500 years) than in Europe (over 33,000 years), and much of her presence there may have been down to back-migration from Europe. This tends to rule out the Levant, Anatolia, and Bulgaria as homeland or source regions for HV, so we need to look for a route of entry into Europe for HV other than the Levant and Anatolia.17

  A team of Estonian geneticists led by Richard Villems and Toomas Kivisild, whose seminal mtDNA work has brought Indian Palaeolithic genetic prehistory to the fore, have much to say on the origins and spread of HV. They point out that the earliest roots of HV are found in South Asia (in north-west India and Kashmir, perhaps 40,000 years ago), but that the Trans-Caucasus was the site of her first West Eurasian blooming.18 (See Figure 3.4.) The Estonian work has suggested that the region around the Caucasus Mountains locked between the Black Sea and the Caspian was the Palaeolithic genetic starting point for several important early European migrant maternal clans, of which the most important was HV.

  To many people, myself included, the word ‘Caucasus’ conjures up images of fierce and independent peoples in the south-west of the former Soviet Union, a region whose famous mountain range, the Caucasus, gives us the name ‘Caucasian’ – which for some obscure reason is used to describe Europeans as a whole. A tight patchwork of Caucasian languages certainly bears out this sense of ancient diversity. Hemmed in by a mixture of Indo-European and Altaic languages to the north and south, the Caucasus has two unique and ancient language families of its own, North Caucasian and Kartvellian. The region, bounded on the west and east by two inland seas and spanned by the Caucasus Mountains, forms the only usable corridor between Armenia and Azerbaijan down in the Levant and European Russia to the north (see Figure 3.4).

  Can the male chromosome help any in tracing a second migration to Europe? To make up for the limited accuracy of dating with Y chromosomes, they are much more illuminating in their intraregional specificity than mtDNA. Notable is an enigmatic male clan (see Figure 3.5) which I shall call Inos, after Seth’s son Enos. Inos is almost exclusively European. According to the Leicester-based geneticist Zoë Rosser and colleagues, the relatively even distribution of this male clan indicates an early entry to Europe. Italian geneticist Ornella Semino and her colleagues from America are more specific, pointing out that the predominance of Inos in Ukraine and the Balkans suggests an association with the HV maternal clan and with the Gravettian culture. Like HV, Inos does not have a clear origin in the Levant, so a Trans-Caucasus route is a possibility.19

  A gap in occupation of the Near East?

  Before we get too carried away with such genetic speculation, we need to be clear on what the archaeological record tells us about the earliest modern human occupation of the Caucasus corridor. In the last chapter we saw that, at least in West Eurasia, the arrival of modern humans was associated with a change from the Mousterian (Middle Palaeolithic) tools used by Neanderthals to the Upper Palaeolithic tools used by Modern Europeans. In the Levant, the earliest changes from Mousterian to transitional Upper Palaeolithic industries have been found to the south, in what are now the Negev and Sinai Deserts, between around 45,000 and 47,000 years ago (see Figure 3.1). There was then a long gap in habitation of around 10,000 years before the south was re-occupied by humans making Early Upper Palaeolithic tools of the so-called Ahmarian type, a culture which lasted until 20,000 years ago. This hiatus coincided with a climatic worsening characterized by two cold, dry snaps climaxing 45,000 and 40,000 years ago.20

  Between 34,000 and 40,000 years ago, the world remained dry and cold, and there was no significant Indian monsoon. The prolonged warming that began again 34,000 years ago invited reoccupation of the drier parts of the Levant.21 This time there was another reoccupation, of a famous cave far to the north at the top of the Fertile Crescent in the northern Zagros Mountains. Shanidar Cave nestles at the southern gate of the Caucasus corridor.

  Shanidar Cave (see Figure 3.1), near where the modern-day borders of Turkey, Iran, and Iraq come together in northern Kurdistan, just south of Armenia, was made famous at the end of the 1960s by Ralph Solecki, an archaeologist who discovered what he regarded as evidence of Neanderthal burial with flowers. The Neanderthal occupation lasted from over 50,000 years until about 46,000 years ago. Then, after a climatic gap of 10,000 years, another human species became its new tenant. A transitional Upper Palaeolithic industry known as Baradostian appeared in Shanidar Cave around 35,500 years ago and lasted until 28,700 years ago. This is presently the best evidence for modern human occupation at the southern entrance to the Caucasus around that time.22

  Also about this time, 36,400 years ago, the first Upper Palaeolithic colonization of European Russia appeared high up the river Don, at Kostenki, due north of the Caucasus.23 The so-called Spitsynians made tools from flint imported from 150–300 km (100–200 miles) away. The Kostenki location later became famous for its extraordinary complex mammoth-based culture, between 24,000 and 33,000 years ago, but the pioneer Spitsynians showed nothing of this.

  Several archaeological experts on Europe before the ice age see European Palaeolithic prehistory as having several distinct early phases of increased occupation corresponding to climatic improvement. The first of these, the Earliest Upper Palaeolithic between 33,000–45,000 years ago, was characterized by the spread of the earliest Aurignacian technology, which we have already discussed. The second phase, the Early Upper Palaeolithic between 24,000–33,000 years ago, heralds the start of the high cultural peaks of the Upper Palaeolithic. Cultures taking off from around 30,000 years ago, during this phase, are known collectively as ‘the Gravettian technocomplex’, although local name variations add confusing variety. Although the Graveltian really constitutes a third phase of high occupation and new culture in Europe, Palaeolithic expert Clive Gamble argues that the important cultural threshold of this second era in Europe as a whole started in north-eastern Europe around 33,000 years ago, for example at Kostenki on the Don, and not with the Gravettian, farther south-west, 30,000 years ago.24

  The main cultural innovations of the Gravettian were the systematic mining of high-grade raw materials, high-grade cave art, elaborate burials, large bone tool sets, the use of bone – particularly mammoth – for houses (see Plate 22), and highly specialized mammoth-hunting. In summary, the Early Upper Palaeolithic cultures not only reveal an accelerating advance in European representational art, use of exotic materials, and burial practice, but may also have represented an intrusion of peoples carrying the seeds of such cultural practices from Eastern Europe. This invasion of culture and people did not remain in Eastern Europe, finding some of its highest artistic expression in southern France and northern Spain.25

  Can we reconcile the HV genetic signal of modern human expansion into Northern and Western Europe with the arrival of the Early Upper Palaeolithic around 33,000 years ago? The short answer is yes: there is a clear, single female genetic signal at the right date, there is an obvious route for her to have taken, and there is a male counterpart. The HV clan may thus represent the earliest movement of modern humans into northern Europe via the Trans-Caucasus.

  Where did she go next? Probably everywhere. As we have seen, HV is the commonest clan in Europe, but her descendants are still commoner in northern and south-western Europe than around the Mediterranean coast. She had a daughter – the European
V clan – much later, around the Pyrenean area, but recent studies show an older pre-V type in the Trans-Caucasus, the northern Balkans, southern Spain, and Morocco, suggesting an early westward progression across Europe from the Ukraine.26 (See Figure 3.4.)

  Could the ancestors of the Early Upper Palaeolithic people have come from farther east?

  There is, however, just the possibility that HV’s homeland before she moved into Europe was not the Trans-Caucasus but further east, across the Central Asian steppe. In this scenario the north Caucasus region would have received migration from Central Asia, east of the Caspian Sea, rather than from Armenia in the south. Essentially this means moving north into Russia via a route to the east of the Caspian Sea rather than to the west of it.

  Much has been made of a group of perfectly preserved Caucasoid mummies found in Urumchi, Chinese Turkestan, and dated to about 3,000 years old, and others in Central Asian locations along the Silk Road. Whether these represent a Neolithic spread of Indo-European-speaking tribes towards the East or descendants of some more ancient local population, there is actually archaeological evidence for the occupation of Central Asia by modern humans from before 40,000 years ago. Early Upper Palaeolithic technology has been found in two sites in the Russian Altai, spreading to south-east Siberia by 39,000 years ago. This does mean there were modern humans in Central Asia early enough to have provided the base for an invasion into Europe through Russia.27

  A third of today’s Central Asian genetic stocks are West Eurasian ‘Nasreen’ maternal lines. Half of these consist of HV stock. The usual explanation for this ‘Europe in Asia’ presence is a recent eastward European emigration along the Silk Road. The problem with this argument is that HV’s common European daughter V, who might be expected to have joined such a movement, is absent from Central Asia. Furthermore, most of the other West Eurasian Nasreen lines in Central Asia look more like they have come directly from India than from Europe. In other words, HV could have originally come from South Asia, round the east of the Caspian Sea, and then gone the other way, westward into Europe (see Figure 3.4). There is Y-chromosomal support for this view of an alternative east-west route for South Asian genetic clans entering Europe via a Central Asian detour.28