A follow-up from an earlier post. Looking at a transect of Roman DNA I made the assertion that modern Roman Italian samples reflect the rural hinterlands of Lazio, which repopulated the city after its massive population loss of the 7th-centuries. This separate post is probably warranted because taking into account comments, I have reread and rethought, and I think I am going to update a few views.
But first, something I won’t update: it seems clear that Imperial Romans were genetically distinct and quite cosmopolitan in comparison to their Republican predecessors, but neither did they leave a clear imprint down to the future. The histories are quite clear that Imperial Rome was a reflection of the whole Roman Empire, with eminent intellectuals and aristocrats congregating from all corners of the world-state. That being said, the results from the paper confirmed the weight of the eastern provinces in their influence and demographic heft.
And yet for all that heft, the scions of the eastern provinces who settled down in and around the Eternal City left few descendants judging from modern Italian DNA. Why? Because cities were massive demographic sinks in the best of times, with endemic disease, combined with periodic shocks like plagues and invasions.
With the decline of the Pax Romana, and the shattering of the Mediterranean system with the rise of Islam, the demographics of the Roman people no longer reflected the world of antiquity. Rather, Romans became Italians once more, more or less. But, there were subtle differences from the Republican Romans. Modern Romans seem to be placed as you would expect between North and South Italians. The Italian peninsula as a whole seems to have received more “Pan-European” genetic influence since the Iron Age. The cumulative impact of Goths, Lombards, as well as the slave trade and the remnant of Imperial cosmopolitanism, has likely made a difference.
I think it should be fairly obvious that the imperial streams of slaves would have regional components as well. The first authors already noted that Germanics had bigger problems with heat, thirst and the sun, as they put it. So I’d assume that most of the agricultural slaves in the Latifundia of the South (e.g. Sicilia) were coming from the Levante and North Afria rather than from North of the Alps. So where traders and teachers, including slaves for those positions – it is interesting that some stereotypical specialisations of ethnoracial groups persisted to modernity. To give an example: A much higher proportion of Poles and Serbs became construction workers in other European nations and North America than Greeks, Armenians and Lebanese, which in turn became more often small traders and shop keepers, including restaurateurs.
So we can be quite sure that most small traders, a lot of the teachers (Greek!) and slaves for simple works in Rome, all came from the East. Just think about the issue with sophistry described in the historical accounts and the introduction of Eastern cults (including Judaism and Christianity) with people from the East. That’s the mass phenomenon we are looking at and a lot of them became freedmen, brought their relatives and so on.
In the North of Italy and especially beyond the Alps, a much larger portion of the slaves should have been of Northern descent. So even though some Northerners came down and some Southerners up, the vast majority of slaves and small workers, not just higher level traders and elites, would have come from the respective sources.
These slaves and traders however would have been there mostly for some generations or as long as the city was prosperous. They had short roots in the country so to say. So even if they survived the onslaught and deterioration of the Western Empire, a large portion would have simply left not just the city, but the region.
Take as an example cities like London, Paris or New York today. If the cities would no longer provide the prosperity, or at least promises it can keep up today, who would leave first? Obviously those with the short roots, because that’s why they were coming in the first place. If you came to a place in the first or second generation, you are also more likely to leave. And the reproduction of slaves and the lowest classes was highly dependent on the system behind it, which did step by step even before the collapse of the Empire. With plagues, economic downgrading and last but not least Christianity. All the dependent masses of proletarians and slaves lived from the urban system. Once it was gone they had no base for living.
So the top and newcomers would have simply left, the lowest would have just died out and the remnants dispersed. It is true what you say about urban sinks, but that just adds up to the overall picture.
Also, I’m pretty sure that the impact of the Germanics and rather unaffected Northern Italian provinces will be proven to be big.
Because we know from all historical examples what such constant wars and occupations did to regions. In a lot of places in Central Europe, e.g. the Holy Roman Empire after the 30 years war, whole regions were largely repopulated from places which did better. This might have been even neighbouring provinces and tribes, but still, not the very same people!
So I’d assume that not just the city of Rome itself, but the whole “hinterland” of the urban centre was heavily affected by the events at the end of the Western Empire. I can’t imagine a situation in which this would have been not the case. Its virtually impossible.
What we might see is therefore a repopulation event from the North of already mixed Northern Italic-Germanic people. These shifted the whole population structure of the Northern half, from the more secure and fertile places which remained largely intact. Something like the founding of Venice should give us a hint. Whole elites, but even commoners, whole tribes and communities were on the move in these times. If the research goes on, we will see that some places did better than others and therefore had a bigger impact on the long term population structure. And even thoug cities were demographic sinks most of the time, it was not a simple city vs. rural calculation. Mostly because a lot of the rural areas will be proven to have become largely “deserted” too.
That chart on the right is weird (most of the % don’t even add up to 100). It makes it look like Modern Romans have no Neolithic Farmer, East Med (CHG/Iran) or Hunter-Gatherer ancestry. What does “European” and “Mediterranean” mean anyway? Obviously those are made up of the earlier components. The admixture analysis in your previous post shows those same 3 components (plus Steppe) in Iron Age and Modern Romans, with very similar proportions.
Hello Razib, long-time reader, first-time poster. Please see the post discussing your blog entry on eupedia:
https://www.eupedia.com/forum/threads/39501-Moots-Ancient-Rome-Paper/page7?p=589927&viewfull=1#post589927
Hmm, with their roughly 50:50 split of West Mediterranean / East Med + Mid East ancestries, the ancestors of the Ashkenazi Jews seem to be absolutely typical urban Romans. Supposedly they never ceased being city dwellers … I wonder what gives?
(The admixture in their lineage is sex biased in a predictable way. I wonder what the paper says about the sex bias of admixture in Rome in general?)
“Why? Because cities were massive demographic sinks in the best of times, with endemic disease, combined with periodic shocks like plagues and invasions.”
Is this true in developed nations since the sanitation movement in the late 19th century and the antibiotics revolution of the early 20th, or is it just too early to tell?
I can imagine urban populations are still less fecund per household, due to living costs, but a very large % of the population in these nations are urbanized, and without major disease outbreaks reducing the amount of children that live to procreate…
The main reason for Western urban populations to have less children is the individual value question. Rural people are more family oriented and conservative.
Liberal and individualist people with a postmodern ideology don’t have many children as a rule regardless where they live.
The cities pull more Liberals, educated and individualists in general, they produce more of them in their social environment, the Liberal education, jobs, anonymity, promiscuity etc.
The best test is the direct comparison. Most mainstream couples have between zero and three children. More is rare. Those on the countryside more on average, but just moderately so and still far from more than three. If a career oriented woman with her hedonist man in a lose relationship goes to the country, they don’t become fecund out of a sudden. They just live in a village, thats it. Still the same “values” they brought in.
Strictly religious people, like strict Catholic or othodox Jewish, have on average much more children almost regardless of where they live and what job they have. They can live in the largest cities and as long as their communities are vital they have large families.
So the deeper reason is not the city in itself, but the principles and personal priorities people have, their view on and plans for their life, the peer groups and community which influences and supports them. The Western urban social environment is good in making even naturally fecund and child loving people psychologically infertile.
For a wealthy farmer with enough land and work to do, many children are more productive and easier to raise. So this is the ideal situation, especially if non material values are not so much in favour of many children, like in Christian and even worse postmodern Western countries.
But its much too easy to see it that way, it always was, even in ancient Rome.
Where we have the records of Roman families, its not just child mortality, they had a low birth rate in absolute terms and relatively in comparison to lets say Germanics and Slavs. Tacitus described it and he was right. In the urban context it was just worse.
Same like today.
Now we have in Western Europe birth rates as bad or worse on the countryside as we had in the cities just some decades ago!
So the main factors are socio-economic incentives and the dominant ideology.
That comes first, urban or rural second.
That being said, the results from the paper confirmed the weight of the eastern provinces in their influence and demographic heft.
I think this is true, though the paper has a somewhat odd way of confirming this, by assigning the imperial era site samples to a present day Eastern Mediterranean cluster.
But this cluster itself is a composite that probably includes Italian and Balkan outflow. It needs analysis in terms of the proximate populations which were about at the time: Anatolia Iron Age, Lebanon Roman, Mycenaean. That will tell us what the true signal is.
The alternative explanation, that the overall Central Italian population was pulled far southeast during imperial times, and then almost as strongly north after the fall of the empire, would require a shockingly low contribution of Iron Age/early classical Italians to modern central Italians. I am seeing these models circulating around, and based on my priors about continuity in Mediterranean and Near Eastern populations, color me skeptical.
If Lebanese and Palestinian Christians are presumed to be ~80-90% Bronze Age Canaanite, is it really plausible that contemporary central Italians are heavily Greek, Levantine, and Germanic all at once?
The “city air” explanation seems much more elegant for now.
One of the things that actually makes it hard to get a read on continuity over time is that judging by the data that has got through to the Eurogenes blog project’s PCA, there is a quite of a lot of dispersal in the pre-Imperial samples, compared to present day.
Of 11 Iron Age -> Republic samples, 2 are significant outliers (RMPR437 and RMPR475), and even within the remaining 9, there’s quite a bit of dispersal in ancestry from RMPR1 Protovillanovan and RMPR474 and RMPR473 which are fairly close to North Italian, to samples which are a bit more shifted towards Basques (who seem to be a typical Iron Age Iberian/South France population who have closed off) and Sardinians. So it seems likely that there is the effect of population movements and diversity before the Imperial period as well.
There are even more questions about how representative the Imperial and Late Antiquity samples are, and their dispersal.
It’s hard to put a number on continuity considering all the above. That said, although thinking of the post-Late Antiquity population as purely Central European Germanic+average of Imperial Period samples seems off (post-LA and present day seem too slightly EEF / Southwestern European for that?), I could see certainly it being under 50% from the Iron Age though, from eyeballing the samples. The centre of a huge empire is going to have some different levels of continuity over time than the peripheries, unless it has a huge advantage in population size!
Do you know of any unpublished data or an ancient dna study in progress on the Neolithic and PPN period of Northern Mesopotamia? With Northern Mesopotamia I mean South-Eastern Turkey, Northern Iraq and Northern Syria.
May all the leftists move to large cities and live well in peace… without having many children.
Speaking of city air and fecundity, a new paper claims an order of magnitude difference in nonpaternity in poor urban vs low density rural areas. Tbe method is Y chromosomes. But I wonder if the city area NPEs are just adoption of orphans and abandoned children. BTW in low density rural areas the diversity of Y may be low or nonexistent in the first place, so using Y DNA there is bound to underestimate the rate?