Idiosophy

A physicist loose among the liberal arts

Skin Color in Roman Britain

There has been quite a stink over the past few weeks about what color skin the Romans in Britain had.  The BBC put a dark-skinned Roman official in a children’s cartoon history program, and the denizens of social media were off to the races. [1] Mary Beard and Neville Morley picked up the standard for the classicists. Among the alt-right antagonists was the pop market-analyst N.N. Taleb, who got famous for coining the term “Black Swan”, but seems not to have the chops to back up his reputation. The noise from the racists got so loud that the Faculty of Classics at Cambridge felt obliged to weigh in. This is kind of amazing to me. I was sure everyone knew that the Roman Empire stretched well into Africa and Asia.  They even had an emperor called “Philip the Arab“, for crying out loud!  When the Roman generals chose troops to occupy a far-flung province, prudence dictated that their preferred troops not have any language in common with the subject population except Latin.  So claiming that the Romans in Britain were all light-skinned seems unsupportable.

But let’s see what they’re saying.  As nearly as the the alt-right are willing to be understood, they’re basing their objections on a map of genetic markers in the current British population.  A 2015 study of the fine-scale genetic structure of the UK doesn’t show much sign of African genes.  They think this “hard science” is much more important evidence than squishy, historically-based evidence, even when the historians have eyewitness accounts.  The Guardian article I linked at the top lists some good reasons why genetic surveys might not be the best evidence for claims about ethnicity 2,000 years ago.

I’d like to add another reason:  There resemblance between the genetic survey’s clusters and the patterns of family names in the UK is not strong. Leslie et al. tracked autosomal DNA, not mitochondrial, so there should be strong parallels.  Surnames and genes are inherited from the same ancestors, after all. A map from the Nature article looks like this:

Leslie et al. map of clusters

Clusters of genetic similarity.

In the course of tracking down hobbits, I found the work of James Cheshire and his collaborators,  which shows a strong relationship  between clusters of family names in the UK and the cultural/administrative regions of the country.  Here’s a map published by Cheshire, Longley, and Singleton in 2010.

Clusters of family names

There are some general resemblances. The big homogeneous blob in the East and South East is there, though family names don’t let it extend all the way to Northumberland.  I can see hints in the light-blue smear in the North West and the purple smear in the southern West Midlands. Below the coarsest level, though, the two distributions do not resemble each other very well.  In particular, the genetics suggests that the people of Pembrokeshire (the southern peninsula of Wales) are affiliated with the Scotch-Irish borderlanders.  Family names suggest they’re more like the West Midlanders.  And if there’s a family resemblance between Yorkshiremen and Cornishmen, it doesn’t show up in their names.

The conclusion I draw from this is that the genetics is pointing us in a common direction with external markers of family ties. There really is something there, and a salute to the geneticists who have managed to tease it out. However, the signals are accompanied by a lot of noise.  We can’t yet use genetic evidence with any precision.  When we have a person standing next to an Ethiopian legionary on Hadrian’s Wall and writing about it, it would be foolish to try to contradict him with our rudimentary genetic surveys.

Post-scriptum: I really enjoyed the line, “History is written by the winners; genetics is written by the masses.”


[1] Sorry.

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4 Comments

  1. Hamar Fox

    This whole thing has been one set of know nothings arguing against another set of know nothings. Taleb’s sources were garbage: The Leslie study didn’t even look for sub-Saharan genes (there are plenty of papers that clearly show Britons have no sub-Saharan ancestry, but Leslie’s paper isn’t one of them). The Guardian’s article was garbage: They irrelevantly talk about how uniparental markers can be lost from the gene pool, even though only autosomal evidence was even cited in the first place. Your point about a surname study not matching with Leslie’s findings is garbage: There’s no particular reason naming patterns would strongly correlate with genetic clusters within a population (even though the two maps *do* show a striking similarity, so your point was doubly weird).

    Genetics isn’t on the side of Beard, but Taleb made an absolute pig’s ear of demonstrating that fact. I’d actually characterise him as a know-nothing who was accidentally correct. And Beard simply as a know-nothing.

    • Joe

      Your standards for knowing things seem to be very high. Do you have a positive contribution on the topic?

  2. Hamar Fox

    There are almost limitless errors to correct in this entire debate, so it’s difficult to give a catch-all refutation of every idiocy spluttered.

    Regarding your surname/autosomal DNA correspondence argument and the contingent ‘genetics is in its infancy’ point, well, no: two different families of surnames existing side by side says nothing about whether members of said two groups should be genetically dissimilar from one another. If they were originally similar, and inbreeding within those groups was too low to create a unique signal within each group, there is no reason why they wouldn’t remain similar. In addition, there may be significant genetic exchange between those two regions, thus preventing any kind of significant divergence between them.

    It would be somewhat stranger for there to be genetic divergence *within* a surname-group, although still not that strange. An originally-similar group may well become divided, with inbreeding occurring within each newly divided sub-group (which is what we see with the Welsh). Likewise, a cultural bond may exist between two originally genetically dissimilar groups (such as two populations conquered and culturally imposed upon by a third party) or an originally similar group may colonise new territory, in one place replacing the locals and in another admixing with the locals, thereby creating two culturally similar but genetically dissimilar populations. The list goes on.

    The genetic map is superior to the surname map. The genetic map picks up all the parts of the surname map you’d expect to be genetically distinct (such as the ‘West Yorkshire’-branded genetic region, which perfectly corresponds with the same region on the surname map). Yet the genetic map goes further and correctly identifies divisions *within* some surname-regions. The best example is obviously the genetic distinction within the South West surname region between the Cornish, who are an ethno-linguistic group, and Devonshiremen, who are English. In fact, I’m not even sure why the surname map groups them together, since Cornish surnames are clearly very distinct for the most part. Additionally, the genetic map is powerful enough to distinguish between the North and South Welsh, who are physically distinct and distinguished by generations of mutually-exclusive inbreeding, but culturally similar.

    The question of whether sub-Saharans made a genetic impact in Europe has been answered for years. The answer is: in Portugal, a bit; in Sicily, a bit; in Spain and mainland Southern Italy, so-so; everywhere else, nope. I’ve read some highly amusing pieces recently from ideological ‘intellectuals’ that strongly suggest they’re gearing themselves up for a ‘black people have always been common in every era of European history’ narrative, which, though ripe with comedic potential, as a geneticist can only make me cringe. In fact, I doubt the hilarity of it will be anywhere near enough to compensate for all the gruelling work I’ll have to do correcting simpletons.

    • Joe

      A quick look around the web shows that this is the closest you’ve ever come to making a contribution to a debate, so it’s approved. Note, though, that you’re the only one talking about sub-Saharan Africa, which tips your hand.

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