The science of human history as written by Herodotus

By Razib Khan | March 28, 2010 2:15 am

The following passage is from the epilogue of The Real Eve: Modern Man’s Journey Out of Africa by Stephen Oppenheimer:

In this book I have offered a synthesis of genetic and other evidence. Everything points to a single southern exodus from Eritrea to the Yemen, and to all the non-African male and female gene lines having arisen from their respective single out-of-Africa founder lines in South Asian (or at least near the southern exit). I regard the genetic logic for this synthesis as a solid foundation, and I have based the rest of my reconstruction of the human diaspora upon it. Obviously, the ‘choice’ of starting point (mine or theirs) determined all the subsequent routes our ancestors and cousins took. Tracing the onward trails is only possible as a result of marked specificity in regional distribution of the genetic branches The geographic clarity of both male and female gene trees is a big departure from the fuzzy inter-regional picture shown by older genetic studies. The degree of segregation of lines into different countries and continents is in itself good evidence that once they got to their chosen new homes, the pioneers generally stayed put, at least until the Last Glacial maximum forced some of them to move. This conservative aspect of our genetic prehistory also provides a partial explanation for the fact that when we look at a person, we can usually tell, to the continent, where their immediate ancestors came from, and underlies differences that some of us still call ‘race.’

Oppenheimer wrote the above in the early aughts, as his book was published in 2003. Much of this is generally in line with the ‘orthodoxy’ of the day. I believe that Oppenheimer’s assertion that there was one southern migration out of Africa by anatomically modern humans has gained some advantage over the alternative model of two routes, northern and southern, over the past ten years (Spencer Wells’ The Journey of Man sketches out the two wave model). Other assertions and assumptions have not stood the test of time. In particular, I would contend that generally the ‘conservative aspect of our genetic prehistory’ can no longer be taken for granted. Specifically, it seems likely now that much occurred after the Ice Age and during the Neolithic.


420px-AGMA_HérodoteThe false inferences of the early aughts were due to two primary problems. First, they relied heavily on the powerful new techniques of extraction and analysis of uniparental ineages; the male and female direct line of descent. Concretely, mtDNA and the nonrecombintant portion of the Y chromosome. The lack of recombination allows for relatively easy reconstruction of phylogenies assuming a coalescent model. Second, the inferences attempt to make connections between the patterns of variation in modern populations, and what one may infer about the past from those patterns. Obviously constructing a phylogeny, or plotting haplogroup frequencies as a function of geography, is rather straightforward science. But using these results to generate inferences of the past is often more of an art than a science, and implicit assumptions lurk behind the causal chains. Consider for example the utilization of modern Anatolian (i.e., Turkish) genetic variation as a reference for the expansion into Europe of Neolithic farmers from the Near East. This of course presumes that modern Anatolians are a good proxy for ancient Anatolians. There are various suggestive reasons for why this is a plausible assumption, but assemble enough plausible assumptions, and rely on their joint likelihood, and you construct a very rickety machinery of possibility.

In early 2007 I began to have serious doubts about the orthodoxy of genetic conservatism. The primary trigger was the story of the Etruscans. Here is the crux of the issue: there are two models for the origins of the Etruscans, first, that they were the pre-Indo-European autochthons of Italy, or, that they were the migrants from the eastern Mediterranean, in particular Anatolia. The second may seem an outlandish hypothesis, but there were several tendrils of evidence to support it. But perhaps the ‘support’ which weighed most against it is that the fact that the Anatolian model has an ancient source, the Greek historian Herodotus. I should perhaps put historian in quotes as well, because Herodotus is often viewed more as a repeater of myths, and derided by some as the ‘father of lies’ (in this he stands in sharp contrast to contemporary perceptions of the ‘modern’ Thucydides, though revisionists have begun to challenge this narrative). In contrast, the model that Etruscans are indigenous to Italy, and that their ‘exotic’ foreign traits were simply acquired through trade and cultural diffusion, dovetailed well with the post-World War II ‘pots not peoples’ paradigm. That cultural change was ubiquitous, while at the same time populations were immobile. It was boring, prosaic, and conservative, and so an ideal null hypothesis.

But here it turns out that Herodotus was right, and archaeologists were wrong. Genetic analysis of modern Tuscans from isolated villages shows that some are surprisingly closely related to extant eastern Mediterranean lineages. Genetic analysis of Tuscan cattle showed that they were surprisingly closely related to extant eastern Mediterranean lineages of cattle. Finally, extraction of ancient Etruscan DNA showed that they were closely related to extant eastern Mediterranean lineages. The overlap was often with Anatolia, and combined with fragmentary linguistic and archaeological data, the evidence clearly points to an exogenous origin for the Etruscans. The boring null hypothesis was wrong. After these genetic stories gained prominence I went and reread recent archaeological texts on the Etruscans, and there were many models which showed exactly how Etruscan cultural uniqueness derived back to prehistoric Italy. It seems in hindsight that the prior assumption served as an interpretative filter, and people saw patterns that they were primed to see based on what they ‘knew’ to be the history of prehistoric and early Iron Age Tuscany.

Of course to refute the primacy of Oppenheimer’s conservative model of genetics one has to offer more examples than that of the Etruscans, and in particular, examples which are of greater scope and weight. I believe those examples exist. In the early aughts based on the mtDNA evidence the likelihood was that South Asian genetic variation is by and large a product of changes wrought upon the basic elements extant in the region around the end of the last Ice Age. The Y chromosomal data was more confused, though it did imply a closer relationship to groups in western Eurasia. But based on the mtDNA Oppenheimer posited a model whereby India was the mother of all non-Africans, that is, all non-African lineages derived from roots within the Indian subcontinent before the Last Glacial Maximum. This is at sharp variance with colonialist narratives of an Aryan invasion of the subcontinent, and the subjugation of the natives by quasi-European overlords, who are the ancestors of the moder upper castes. The charged ideological import of this model is transparently obvious.

Unfortunately the reality is likely more complex. I suspect that some form of Oppenheimer’s model is correct, insofar as South Asia was likely an important way station for modern humans as they left Africa, and pushed into other regions of Eurasia, on to Australasia and the New World. This interpretation does gain support from mtDNA, the direct maternal lineage. But a new analysis of South Asian genetic variation using a substantial proportion of the autosomal genome implies in fact that South Asians are possibly descendants of an ancient hybridization event between a native population with deep roots in the subcontinent, and a quasi-European population which was exogenous to the subcontinent.* Genetically the quasi-European population is quite close to northern Europeans, similar to the genetic distance between modern Finns and Italians, not trivial, but far closer than that between modern South Asians and Europeans. Was this the ancient Aryan invasion? I remain skeptical of this particular detail for various reasons, as I suspect that the history of the Indian subcontinent is in fact even more complex than has been assumed before (I think it is more likely that the quasi-Europeans came before the Indo-Aryans, who arrived late, and had a stronger cultural than genetic influence).

Finally, there is another region of the world where it seems likely that the old orthodoxies of genetic conservatism will be overthrown. That region is Europe. The scientific orthodoxy of deep time continuity is strong enough that it has percolated into the public consciousness, the leader of the British National Party even referred to the deep roots of white British in demarcating who he believed ‘indigenous people’ of the Isles were. But newer data is more supportive of the hypothesis that in fact Neolithic farmers who arrived from elsewhere are the likely ancestors of most Europeans, not the hunter-gatherers who remained after the Ice Age. Extraction of ancient DNA has yielded a set of results which simply are not explicable assuming the older models of genetic continuity, which were based on inferences made from modern population variation. If I had to hazard a guess, I would have some, though not high, confidence in the following story. First, the indigenous hunter-gatherers are assimilated or marginalized by waves of Neolithic farmers pushing out from the eastern Mediterranean. The demographic expansion does not necessarily sweep outward along a southeast-northwest axis, rather, it follows the Mediterranean and Atlantic fringes, as well as along river systems in the interior. Its impact is weakest in the northeast of Europe, where Middle Eastern crops are least suitable, and the natives have the most time to absorb the cultural toolkit of the newcomers so as to resist their advance. Second, and far later, there was another wave pushing out from the region of the Ukraine to the Volga, likely the ancestors of the Indo-Europeans. Tentatively I would contend that these were the carriers of the Kurgan culture, and also brought the allele for lactase persistence. Again, for ecological reasons the populations of the northeast Baltic and into the forests of northern Russia were most insulated from this push (and non-Indo-European languages persisted in Iberia down to Roman times, and specifically in the Basque-country down to modern times, though I suspect this is a function of distance). So modern European populations may be assumed to be tri-hybrid, first a synthesis of Middle Eastern farmers overlain upon the Paleolithic substrate, and second a synthesis of Indo-Europeans from the east overlain upon pre-Indo-European substrate. Unlike the case of India I suspect teasing out these patterns in modern populations is more difficult because the genetic distance between the three ancestral populations is far smaller than between the indigenous peoples of India before the quasi-Europeans arrived.

This leaves much of the world untouched by my speculations, but I believe showing that the genetically conservative null hypothesis is now in serious doubt in South Asia and Europe is sufficient to knock it from being a necessarily default assumption through which we must filter our interpretations. I do not believe that the reordering of human variation and the welter of population movement after the Ice Age was equivalent in effect to the Out of Africa migration, but I do believe that it was important enough to make the world of 2000 BCE very different from that of 15000 BCE in regards to genetic variation. In some cases, such as Central Asia from the Caspian to the Taklamakan the world of 2000 CE is fundamentally different from the world of 0 CE.

I will then end with a prediction, one in which I do not have much confidence, but which may no longer be wrong on the face of it with these new data in mind. Here is a passage from page 7 of Jared Diamond’s Guns, Germs, and Steel:

Initially, archaeologists considered the possibility that the colonization of Australia/New Guinea was achieved accidentally by just a few people swept to sea while fishing on a raft near an Indonesian island. In an extreme scenario the first settlers are pictured as having consisted of a single pregnant young woman carrying a male fetus…..

Let me stipulate that Diamond seems skeptical of the extreme model, but it illustrates the consensus that Australian Aboriginal populations are descended from the first settlers. That is, the modern populations of indigenous Australians are the direct descendants of those who swept Out of Africa along the fringe of the Indian ocean, through Southeast Asia, and arrived in Australia (more specifically, Sahul), on the order of 40 to 60 thousand years ago. From what genetic data I have seen this may be true. But I do not know of any extractions of ancient DNA, and it seems to me that the analysis of the phylogenetics of Australian Aboriginals is relatively sketchy. Therefore, I will suggest that within the last 10,000 years there has been a major new migration of people into Australia, and the modern range of genetic variation of Australian Aboriginals is significantly different from that of the populations of the Ice Age. I suggest this primarily because the dingo arrived within the last 10,000 years, more likely as recently as 4,000 years ago. With the expansion of the utility of ancient DNA extraction and analysis this question may be answered in the near future. I would still bet I’m wrong with the hypothesis I just offered, but I’m far less sure than I would have been 2 years ago.

Note: This post emerged from a conversation I had with Kevin Zelnio and Dave Munger.

* I say ‘quasi-European’ because the population may have origins outside of the boundaries of modern Europe at the Urals. Perhaps in western Siberia. Additionally, the idea of ‘Europe’ is relatively new, and exhibits little ancient cultural coherency.

Image source: Wikipedia

  • toto

    I will suggest that within the last 10,000 years there has been a major new migration of people into Australia, and the modern range of genetic variation of Australian Aboriginals is significantly different from that of the populations of the Ice Age. I suggest this primarily because the dingo arrived within the last 10,000 years, more likely as recently as 4,000 years ago.

    Australia is almost connected to Papua-New Guinea by the Torres Strait islands. The first Aborigines may have come on rafts of fortune, but after the diffusion of reliable seafaring technology, travelling to and from Australia posed no major difficulty.

    I’m not sure if the presence of dingos indicates a “major” arrival of new people. Once a few dogs found themselves stranded on the island (perhaps imported by settlers, perhaps left ashore by travellers), they may well have spread quickly on their own due to favourable ecological conditions (open niche FTW!). I understand that dingos are basically feral dogs, in that most of them live independently of humans – and seem to do quite well that way. Also, if dogs had been deliberately introduced as domestic companions, and if their importers had leeft a significant mark on the Australian population, we would expect to see a tradition of keeping and breeding domestic dingos in Australia.

    Wiki says: “Linguistic and genetic evidence shows that there has been long-term contact between Australians in the far north and the Austronesian people of modern-day New Guinea and the islands, but that this appears to have been mostly trade with a little intermarriage, as opposed to direct colonisation. “ That’s well enough to allow for a canine takeover.

  • John Emerson

    There are lots of ways of making the problem of long-distance diffusion more empirical and less schematic.

    1. Besides the northern European diffusion of the last 500 years or so, during historical time (since about 1000 BC or later) there have been four major long-distance diffusions: Malayo-Polynesians from SE Asia to Madagascar and Easter Island; Turks from NE Asia to the Mediterranean; the Bantu from central Africa to South Africa, and Inuit from Asia to Greenland.

    The Malayo-Polynesians travelled by boat, which is one of the ways that long-distance travel can be made easy. The Turks were mounted nomads. The Bantus were technologically and militarily superior to the original inhabitants of S Africa. The Inuit did use boats, but I’m not sure how much of their travel was by water and how much by land.

    None of these are refutations of the idea of genetic conservativism. They just show kinds of ways that this kind of diffusion could happen. Nomadism rose after 1000 BC, and even oxcarts are only a couple of millennia older. I don’t know anything about the history of boats, but they seem like a better candidate for early long-distance transportation form. A crude boat can be very easily built. (I have read, incidentally, that there might have been a prehistoric Indian Ocean monsoon trade between Yemen / the Horn of Africa and South India, and that there’s genetic evidence for it. I’ve also seen arguments for prehistoric sea contact between the Americas and Asia, though not in large numbers.) The Bantu migration, with cattle and iron, seems like a late version of the Indo-European migrations.

    Absolute distances are not the problem. Beijing and Paris are about 5000 miles apart, and that distance could be negotiated on foot in a few years. The three reasons for not going further that I’ve figured out are motivation (people tend to stop once they’ve found a nice place), an inhospitable, unsupportive environment (without horses the steppe / desert areas of Central Asia are difficult in the best of cases) and human opposition. The last of these is the main argument for conservativism, I think. Once an area is filled up, it’s hard either to cross it or to take it over. But this depends on the relative military efficiencies of the peoples in question. (With human opposition there’s a second contrary factor though. Completely uninhabited areas lack key support necessities like blazed trails, watering places, hostels, etc. and impede travel that way).

    There have also been many peoples during recorded history who developed habits of raiding and long distance exploration for no particularly practical reason. In these cases young unmarried men and outcasts go out to seek their fortune without necessarily being very clear what their goal is, conceivably to occupy land if it’s uninhabited or if the people already there can be displaced. Something like this was a factor in Greek, Viking and Turkish migrations. (These raiding groups are often explained by “overpopulation”, but they seldom or never come from genuinely overpopulated areas like Java, Egypt, or Bengal. They’re a consequence of social structures which don’t have places for everyone.)

    These are just factors to think of when arguing or explaining the conservativism hypothesis. None is decisive, obviously, but they help make it a more concrete question.

  • bioIgnoramus

    “Malayo-Polynesians from SE Asia to Madagascar and Easter Island”: and Hawaii and New Zealand and the islands in between. Very remarkable feats. (If anyone can direct me to material about the voyages to/colonisation of Madagascar, I’d be grateful.)

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  • http://backseatdriving.blogspot.com/ Brian Schmidt

    #3 bioIg – refer to Diamond’s Guns Germs and Steel book for more info (not a lot of info to go on though).

    I’ve been to Madagascar – the people show a striking combination of African and Polynesian facial features, and the language is clearly Polynesian with a few Swahili borrowings.

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    more malayan than polynesian. malagasy is closely related to some languages of borneo.

    http://en.wikipedia.org/wiki/East_Barito_languages

  • John Emerson

    I heard a Malagasy band named Tarika awhile back, and the lead singer said she always gets asked something like “Are you guys African or what?” She and her sister could have passed for East Asian. The sound was very eclectic-sounding, much more SE Asian than African, but not much American or European influence.

    Madagascar is apparently very multicultural and xenophile. There was a story awhile back by an Irishman or Irishwoman whose grandfather had left a family in Madagascar, and when she vicited her cousins were happy to see her, partly because they wanted to fill in the gaps in the family genealogy, which went back several generations on the Malagasy side but was sketchy on the Irish side.

  • http://www.buildinghistory.org/distantpast/ Jean M

    Interesting post Razib. You and I are converging re Europe.

    On India I suspect that the picture is even more complex than the one you outline, but we await ancient DNA.

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  • http://www.rishon-rishon.com David Boxenhorn

    I would propose a null hypothesis that most genetic variation in Eurasia follows the spread of agriculture. That is, in the west, diffusion from the Middle East; in the East, diffusion from central China. As you say, the prior populations provide some variation, especially at the periphery of expansions (Latvia, South India, Java, Japan, Siberia). Later movements like the spread of the Indo-Europeans had less of a genetic impact, I would think, because by and large they were conquests of large native populations by small elites. For a model that took place in historic times, look at the expansion of Europeans in North America. I think that is what the expansion of agriculture looked like: some admixture, but not a lot.

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  • Ponto

    I accept your conclusion to Europe’s peopling. I would add the Mesolithic element in the genetics of modern Europeans is partial and female only i.e very few Mesolithic men passed their dna to modern Europeans. Similarly, New World mixed populations have male European ancestry and female Amerindian ancestry. A one sided inheritance.

    Herodotus was right in one sense, that the Etruscans came from the north eastern Mediterranean. I think the idea that the east side of the Mediterranean is foreign or alien to Europe is rather stupid. The Mediterranean Sea linked all the peoples that lived on its shores especially the east side with the north and west. So the Etuscans are not foreign interlopers but just inhabitants of the Mediterranean who moved from one place to another. The old Greeks had their colonies. What would Southern Italy be without those ancient Greek colonies, and their inhabitant’s dna? My most humble opinion is this: The old Greeks and the old Romans (the Italic speakers) were both I.E speaking immigrants who stumbled into their particular peninsulas of Europe like most I.E speakers with their three fold caste system and weapons galore, and proceeded to make themselves native and the natives foreign. In Italy the native Etruscans, the ones who were there before the I.E speakers immigration, became the foreigners. The old Greeks completely removed the Pelasgians. So Herodotus was half right, which for a Greek old or modern, is pretty good going.

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About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com

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