The genetics of the Lombard folk migration


There are many debates about the period after the fall of the Western Roman Empire in the late 5th century. For example, did it “fall” in the first place? I believe that the concomitant p0litical, social, and economic changes do warrant that word. But another question concerns the “barbarians,” who were mostly German peoples (there are some exceptions, such as the Iranian Alans and the Huns, whose specific provenance is unclear). Were they ethnically and politically coherent? Were they even peoples?

The extreme stylized positions might be outlined as follows:

– The barbarians who filled the political vacuum after the collapse of the late Roman state were coherent preexistent ethnic and political entities of German origin who migrated en masse and engaged in a folk wandering.

– Though their original provenance may have been in bands of German warriors from specific tribes, but the time they appear on the stage of history as we understand it, the barbarians were in fact a motley crew of opportunists of various origins, who adhered to a “barbarian” identity which was created de novo with the collapse of Rome. They were made by the collapse, they did not cause the collapse.

In the late 1990s, Norman Davies in The Isles presents an argument closer to the latter for the British Isles. That is, the Anglo-Saxon character of Britain was to a large effect a function of elite emulation and diffusion of a Germanic culture introduced by what was operationally a late Roman mercenary class. Davies alludes to texts which indicate a substantial native British population in Anglo-Saxon England centuries after the fall of Celtic kingdoms. This is in contrast to the apocalyptic vision of British monk Gildas, who depicts his Brythonic people fleeing before pagan Saxons and being driven into the sea. And, I have alluded to the possibility that the West Saxon monarchy, which later came to the center of English history during the Viking incursion, was in fact in origin Romano-British, rather than German (the early kings have Celtic names).

And yet England was always the most difficult case for cultural diffusion, because to a great extent Roman-British society did collapse. Both the British Celtic language and Christianity seem to have faded from the landscape, so the that the latter had to be reintroduced by Irish and continental European missionaries. Today, the genetics is more definitive, and it seems a substantial German migration did impact what became England, especially the east, what was the Saxon Shore. Though the majority of the ancestry of the people of England today seems to derive from people who were already resident in Britain in 400 A.D., a substantial enough minority seems to have greater affinities to people who were living in the stretch of land between the Netherlands and Denmark.

The case for mass migration on the continent of Europe (with the exception of much of the Balkans) is more difficult to make in a cut & dried fashion because the basic outlines of Romanness were much more intact in the centuries after the fall than in Britain. Though France and Lombardy may have names which derive from German tribes, there is not much that is German about these regions today, and frankly, even at the height of the barbarian rule when conquest and migration were fresh, the non-Roman overlay was likely a thin elite layer. Outside of Britan and the Balkans, the languages of the Roman Empire and the Christian religion maintained their dominance even after the fall of the Roman political order, a transformation of social norms, and the collapse of the economy.

And yet this does not deny the possibility of migration of peoples into this order. In Empires and Barbarians: The Fall of Rome and the Birth of Europe the historian Peter Heather argues that we must not neglect the likelihood that to some extent the arrival of the Germans was one of “folk wanderings.” That the identity of the Franks, Goths, and Lombards, did not emerge ad hoc and de novo through the accrual of military men around a tiny nucleus of German warlords and their retainers. That women and children were also part of the movement into the Roman Empire. Heather, in fact, depicts the Gothic arrival as one of destitute refugees fleeing the famine and chaos outside of the Pax Romana, and their subsequent militarization and rebellion as one forced upon them by the exigencies of their situation.

A new preprint on bioRxiv, Understanding 6th-Century Barbarian Social Organization and Migration through Paleogenomics, clarify these arguments in the case of the Lombards, who conquered Italy in the 6th century. The abstract:

Despite centuries of research, much about the barbarian migrations that took place between the fourth and sixth centuries in Europe remains hotly debated. To better understand this key era that marks the dawn of modern European societies, we obtained ancient genomic DNA from 63 samples from two cemeteries (from Hungary and Northern Italy) that have been previously associated with the Longobards, a barbarian people that ruled large parts of Italy for over 200 years after invading from Pannonia in 568 CE. Our dense cemetery-based sampling revealed that each cemetery was primarily organized around one large pedigree, suggesting that biological relationships played an important role in these early Medieval societies. Moreover, we identified genetic structure in each cemetery involving at least two groups with different ancestry that were very distinct in terms of their funerary customs. Finally, our data was consistent with the proposed long-distance migration from Pannonia to Northern Italy.

The preprint has genetic and isotopic results from two graveyards associated with elite Lombards of the 6th century. The one in late antique Pannonia would be in modern Hungary. The one in modern Italy is near Turin. The late 6th century was a time of tumult in the Roman Empire, as both Italy and the Balkans were subject to massive turnovers of the ethnic and political orders. The movement into Italy from the northeast was a typical one, prefigured by the Goths and other Germans before the Lombards.

From what I know, as far as German barbarians went, the Lombards were rather “raw” and non-Roman (in contrast, some tribes, such as the Goths and Franks, had had relationships with the Roman Empire for generations before they decided to take it over). Though they were nominally Christianized, and elite Lombards persisted in practicing pagan rituals in Italy down to the 8th century, over 100 years after their conquest of the peninsula.

The authors used a lot of “best of breed” methods with their large data set, but the ADMIXTURE plot really illustrates the result fine enough. The blue is associated with Northwest European ancestry (British and white Utah samples), red with Italian ancestry (Tuscan), and green(ish) with Iberian (Spanish mostly). The very light blue is 1K Genomes Finnish. Panel B is the graveyard in modern Hungary, and panel C is the one from northern Italy.

There is a strong correlation in the graves with those being of Northern European ancestry, and having high status via grave goods. The individuals also exhibited some segregation in the graves. Northern European ancestry and Southern European ancestry individuals were clustered together. The Pannonian individuals, whether Northern or Southern European, don’t seem to resemble ancient or modern Hungarians. The isotope analysis indicates that many of the individuals were highly mobile.

Finally, the data was robust enough to do a pedigree analysis. It looks like a lot of these individuals are related. If you look at the plots you can see groups with the label “Kindred.”

There is so much detail in the results that I won’t recapitulate. Just read the preprint and make sure to check out the supplementary text. What I will say is this.

  1. The Lombard migration seems to have been a migration of people of Northwest European heritage into Southern Europe.
  2. The migration occurred during the lifetime of some individuals. These were highly mobile individuals.
  3. There were associated groups with the Lombards, who were genetically distinct, and likely of lower status. Their Southern European character is also distinct from the native population of Pannonia in the case of panel A.
  4. The Lombards themselves had Northern European ancestry which was somewhat heterogenous (probably different tribes and ethnicities). The shift away from Finnish ancestry probably indicates sampling more from western and opposed to central Europe.
  5. Admixture with the local populations and other post-Roman groups began early on.

The ethnocultural distinctiveness of the Lombards is clear from the textual evidence. The genetic data here confirm that in totality. But, The Geography of Recent Ancestry Across Europe, also highlighted a lot of deep population structure within modern Italy, and could not discern much impact of barbarian migration outside of the Balkans across their data set. Why?

It is rather clear that there were population declines across the West Roman Empire in the years after the Gothic Wars. If you read the textual evidence you imagine some sort of catastrophe going on. In human terms it was catastrophic. On the scale of economics, it was catastrophic. But in terms of population genetics, the long-term impact was not that extreme. The local population structure was not much altered because the Roman population base was so high that even a large decline did not induce bottleneck effects, and the German elite was also small enough it did not much perturb the underlying structure which had roots back to the period before the Roman Empire. Even in the first generations of Lombards in Italy, which is the Collego data set reflects, there was intermarriage between German people and others.

The demographic impact of the German migrations was huge on culture, politics, and economics. But it was not huge on population genetics.

A celebration of Cheddar…Man


It’s been a lot of cheddar the past few weeks. Or should I say Cheddar Man, the 9,150 year old Mesolithic subfossil from the area of Cheddar Gorge in England. This individual is important because it’s the oldest remain of such high quality found in Great Britain. And, in the late 1990s, as reported in Bryan Sykes’ Seven Daughters of Eve and elsewhere, the Cheddar Man subfossil was genotyped for mtDNA, the maternal lineage. There were, and are, lots of controversies about the validity of that result due to contamination being common in those early years of ancient genetics.

But today we have Cheddar Man’s whole genome. The preprint is finally out, and I’m digesting. Additionally, there has been a Channel 4 documentary, and a few weeks of media hype all around the implications of Cheddar Man.

This is an exciting time for genetics, history, and heritage. Since Britain is a major center of interest for these topics, it’s not surprising that Cheddar-mania has taken off. To mark this occasion DNA Geeks commissioned a design of Cheddar Man using Prince as a model. That might seem strange, but it probably is appropriate given Cheddar Man’s other-worldly and ambiguous appearance. You can get t-shirts and framed prints.

I’ll probably be posting about the Cheddar Man preprint, which really transcends Cheddar himself, tonight or tomorrow.

Winds of Winter not likely in 2018

George R.R. Martin Throws Even More Cold Water on Winds of Winter Dreams.

Basically, it looks like he will come out with a different book first. It’s hard to imagine him squeezing out the next book in A Song of Ice and Fire before that in 2018.

There were two years between A Game of Thrones and A Clash of Kings. Two years between A Clash of Kings and A Storm of Swords. Five years between A Storm of Swords and A Feast For Crows. Finally, six years between A Feast For Crows and A Dance of Dragons.

If the next book was released now, it would be more than six years. It looks like we’ll go beyond seven years.

The trend is not promising. I’m pretty sure I’m not the only person who is, was (?), a big fan of the series to go through the five stages of grief. It is what it is.

White modern Northern Europeans are genetically more like brown South Asians than brown(ish) ancient Northern Europeans were

The Guardian has a piece by Arathi Prasad, Thanks to Cheddar Man, I feel more comfortable as a brown Briton. Dr. Prasad is a geneticist, so the science is pretty decent (she’s probably seen the documentary ahead of time too).

But there is a curious quirk here and it reveals something about human psychology: modern Britons are genetically much closer to South Asians, like Arathi Prasad, than these ancient darker-skinned Britons. The plot to the left illustrates this (it’s using the Dystruct package). The far right of the top panels represent South Asians. You can see Europeans pretty clearly. Let’s note two things:

1) Modern Europeans (except for Sardinians) share an orange “steppe” component with most South Asians (these are no doubt Indo-European migrations of the Bronze Age)

2) The brown element represents European hunter-gatherers. This element is found at varying quantities across Europe, with the lowest fractions in Sardinians. Though present in South Asians (this may or may not be an artifact to be honest), it’s not present at very high frequencies.

One always has to be careful about taking these proportions as literal representations of ancestral populations. They are not. But what they show is that modern Northern Europeans and South Asians have been touched by the same population movements over the past 5,000 years, and so are genetically much closer than the people who lived in Northern Europe and South Asia 5,000 years ago.

Humans are a visual species. In a pre-modern environment, physical cues were important for group identity, though I suspect just as much due to scarification and tattooing as phenotypic differences due to biology. The fact that Cheddar Man, and Paleolithic hunter-gatherers in Western Europe more generally, probably resembled modern South Asians more than they do modern Northern Europeans (I think they were more likely to be olive-brown than dark-brown, but I’m not confident), is more salient to human folk biology than the fact that modern Northern Europeans are much closer genetically to South Asians than the more “brown” ancient Northern Europeans.

Stuff like this always reminds me of the deep wisdom in Artur C. Clarke’s Childhood’s End. The ultimately benevolent alien species which mentored humanity shielded us from their physical appearance because the knew we’d find it horrifying. The substance of what they did for us, who they were, was going to be less important to immature humans than the fact of what they looked like.

Note: Fst between Sindhi from Pakistan and WHG (Cheddar Man was one) is 0.087. Sindhi from Pakistan and English is 0.023. English to WHG is 0.058 (source). Fst can not be naively interpreted as “genetic distance.” But, this gets at the fact that Mesolithic European hunter-gatherers were very distant from modern South Asians. And widespread gene flow and admixture over the past 5,000 has compressed a lot of genetic differences which were starker across geography in the past.

Ancient DNA and Dystruct


There’s a new preprint, Inference of population structure from ancient DNA, which uses explicit demographic models to make inferences about ancestry. I haven’t dug into the guts of the math, but, the outputs are quite interesting.

What seems to be obvious is that Western Eurasia has a much richer set of models to choose from than elsewhere. European, Middle Eastern and South Asian populations exhibit the greatest difference between Dystruct and Admixture.

Five things paleogenetics tells us about the human past

Since I’m flogging Enlightenment Now, I thought perhaps I should remind readers that Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past by David Reich is out in 1.5 months. For years people have asked me about a book to read to understand what genetics has to say about human history. This is that book.

And yet before you get there, what do you need to know?

Here are five things you should know. Five things that we know with a very high degree of certitude.

  1. Many (most?) modern populations clusters we perceive as clear and distinct date to the last 5,000 years. To give a concrete example, the genetics that we find to be typical of Northern Europeans only comes into being ~5,000 years ago, with the Corded Ware populations. To my knowledge none of the prior populations along the North European plain exhibit the mix of characteristics and ancestries typical of modern Northern Europeans in any way, shape, or form.
  2. Concomitantly, many of the physical characteristics we find typical of modern populations are probably relatively recent configurations due to natural selection.
  3. Non-African populations, whether European, Middle Eastern, South Asian, (South)East Asian, Amerindian or Oceanian, derive from a population expansion that dates to ~50,000 years BP. These populations experienced a bottleneck on the order of 1,000 to 10,000 breeding individuals.
  4. Modern humans are old. Population structure within Africa of modern humans dates to at least 200,000 years before the present, and perhaps even earlier.
  5. Population turnover was ubiquitous. Change was the only constant.

How Craigslist stays at 1 by not moving on from the year 2000

In the open thread, I made a casual comment that I’ve become a bit more skeptical of market efficiencies lately. Remember, in the perfect market, the profit of the firms should converge upon zero. Is this to anyone’s benefit? Obviously, it is to the benefit of the consumer. But what happens in the long term when firms can’t make any money?

This crossed my mind recently in regards to Craigslist. Craigslist is notoriously no-frills and reflects an aesthetic and functionally stuck in the year 2000. The founder, Craig Newmark, is a pretty weird person. The company has 50 employees and does not maximize profit. But Newmark and Craigslist have had a culturally huge impact. They destroyed the newspaper classifieds.

And yet Craigslist stays stuck in the year 2000. This was obvious to me when they went after Padmapper. Padmapper was clearly a service which added value to Craigslist. And yet today I wonder if this behavior by Craigslist actually allows it to continue providing the services it does.

Imagine that Craigslist opens up its API and all sorts of other web applications develop around it. What I can imagine is that Craigslist would become the locus of massive and highly efficient arbitrages. Consider programs which match buyers and sellers in a way which minimizes the “deals” that sellers can today gain from buyers who are naive. Perhaps instead of two people going into an exchange, an ecosystem of “runners” who would transport products.

My thoughts on this are vague and cloudy, but perhaps reduced efficiency and rationality actually means Craigslist can persist for far longer?

When Western Near Eastern Farmers carried North Eurasian Y chromosomes into Central Africa


Whenever you look at a map which shows the distribution of Y chromosomal haplogroup R1b you see two areas where the frequency seems very high. First, Western Europe has a very high frequency. Before 2010 it was commonly assumed that R1b was the heritage of late Pleistocene European hunter-gatherers. Around 2010 deeper analysis suggested perhaps that this was not so, and that the deepest divisions in the phylogeny of Eurasian R1b could be found to the east. The high frequency of this haplogroup then may have been an artifact of the Holocene.

Ancient DNA has confirmed this hypothesis. The high frequency of R1b in Western Europe seems to date to the Bronze Age. Though R1b is not found exclusively in Indo-European peoples and existed at low frequencies in Pleistocene Europe, its current ubiquity in Europe seems likely related to demographic turnover between 3 and 5 thousand years ago.

If I had to bet I think R1b, like R1a, originates among the North Eurasian people who mixed with West Eurasians and Amerindians. The Ma’lta boy, for example, seems to have been a basal R.

But notice a secondary mode of R1b in Africa. This is R-V88. The highest frequencies of this Y chromosomal haplogroup are found in Chadic speaking populations. Chadic is a basal group in the Afro-Asiatic language family. A few years ago a paper was published using autosomal DNA on Chad populations and suggested that Eurasian backflow occurred in deep antiquity. From that paper:

We estimate that [autosomal] mixture occurred 4,750–7,200 ya, thus after the Neolithic transition in the Near East…In Chad, we found a Y chromosome lineage (R1b-V88) that we estimate emerged during the same period 5,700–7,300 ya

A new paper, The peopling of the last Green Sahara revealed by high-coverage resequencing of trans-Saharan patrilineages, really gets to the origin of R-V88, with a massive Y data-set. There’s a lot of other Y lineages that are surveyed in this work, but in the supplements, the figure makes it clear that Sardinian R-V88 is basal to star-like African topologies. The implication here is that the African lineages derive from European ones.

The autosomal paper found Chad populations (though the one in question was not Chadic speaking) seem to share drift from Sardinians in particular. Looking at ancient genomes Early European Farmers seem to have been the primary donor population. Additionally, the coalescence of the African lineages seems to date to 5 to 6 thousand years before the present.

Though not definitive, the association of Afro-Asiatic populations with R-V88 is strongly suggestive to me of the possibility that some western Near Eastern Farmers spoke Afro-Asiatic languages.

Enlightenment Now is out, so there goes my weekend….

Steven Pinker’s Enlightenment Now: The Case for Reason, Science, Humanism, and Progress is now out. I plan on reading it this weekend front to back.

Over the past few years, it’s not a secret that I’ve become more skeptical of the possibilities for humanism and progress. The case for reason and science are obviously clear, but that’s because reason and science aren’t fundamentally normative issues. Humanism and progress are grounded in norms.

Of course, I’ve long been more and more partial to the Scottish Enlightenment, which is more conservative and cautious than that of the French. In the current year, I’m a conservative liberal. But I am gloomy on the prospects for liberalism in the near term future.

Seth Largo distills may of my core intuitions:

Open Thread, 2/11/2018


The podcast that Spencer Wells and I are doing, The Insight, now has got eight episodes up. It’s nice that people are stumbling upon it now. Additionally, we’re pretty satisfied with the uptake. So far. To break out of our “core” audience we need more people to know about us.

First, please subscribe via iTunes, Stitcher or Google Play. Second, mention the podcast on social media. Tell your friends. Third, we have the next two or three podcasts planned, we’re still taking suggestions for ideas and possible guests (so far we’ve had John Hawks and Joe Pickrell on).

I now have Amazon Associates for Canada and the UK. The links to US Amazon items I post on this page should now change depending on your IP.

Cheddar Man changes the way we think about our ancestors. This is a pretty good article. But a few points. First, anyone who followed the literature would have predicted that Cheddar Man would contribute ~10% of the genomes to modern Britons and that he would lack alleles for light skin, but have them for blue eyes. I can’t believe any of the researchers were shocked in light of the La Brana etc. results. Second, we’re not extremely confident that he had very dark skin after the past few years when it’s clear pigmentation genetics involves more than just a few major loci. Seeing as how selection methods have detected lots of sweeps for skin lightening alleles over the last 5,000 years in Northern Europe, it seems implausible that they were as light as modern Northern Europeans, but not necessarily dark.

Spencer and I will probably an episode of The Insight on Cheddar Man after the documentary is out on the 18th (and the paper, probably in Nature).

I’ve blogged on female circumcision/FGM before. There are variations of opinion within Islam on this practice. It is mandatory, meritorious, or there is no comment. Muslims from areas where this is not practiced, such as South Asia or the Maghreb, naturally assume that this is a “cultural practice” that has nothing to do with Islam.

This is simply false. The Shafi school of Sunni Islamic jurisprudence considers female circumcision obligatory, for example. The complicated issue is that a) not all women subject to female circumcision/FGM are Muslim, for instance, in Africa, including Egyptian Copts b) not all Muslims are subject to the practice, obviously. These facts allow all sorts of confusions and obfuscations to emerge.

But the bigger issue is that if you are not Muslim it is not really coherent to say that something is a “cultural” practice as opposed to a “religious” one. Religion is part of the culture, and to a great extent on the reflective conscious scale the defining element of culture. Muslims disagree as to the religious acceptability of many practices. Those disagreements are cultural because Islam is cultural.

Land of Promise is a book I’ve mentioned many times. It’s one whose premises rub me the wrong way: the vigorous mixing of state fiat with the market. I’m not a fan of “industrial policy.” And yet I read the book because Michael Lind, the author, knows his history, and he’s honest about it.

I do think on some level I’m rethinking my commitment to the free market as opposed to institutions, and the short-term benefits of market efficiency set against the long-term advantages of social stability. That’s probably part of a general trend toward conservatism away from libertarianism.

Let’s Ban Porn. Don’t laugh. It took some boldness for The New York Times to publish something as laugh-out-loud implausible. But in the end, I think porn is the symptom. Really we as a culture don’t agree on what sex is supposed to be about. Without that agreement, porn is a sideshow.

Also, the proliferation of porn in the last 20 years hasn’t led to the explosion of sex crimes that critics on the Left and Right would have predicted.

Some of you may wonder about DNA Geeks. What’s the deal? Well, I can tell you that we are building a nice brand, and periodically there are traffic spikes. And the microscope is killing it.

The main sadness for me is that the ratio of R1b to R1a t-shirts sold is like 20:1. But I guess it’s quality over quantity?

While I was taking a Twitter break I got a few DMs about the latest controversy about hours worked by academics:

The stupidest thing on science twitter is how crazy and nasty people get over the idea that you have to work hard in science to succeed. Everybody knows you have to work hard and long to succeed, and yet everyone is willing to outright lie about the truth, lest you be publicly destroyed.

It’s pretty clear some people work fewer hours than other people and do fine. It’s also clear that other people have higher sweet spots in terms of return-on-time-worked. The problem is when people presume there’s a one-size-fits-all formula. I think it would be best if people reacted with a little more charity to those who extrapolate from what’s worked for them.