Angela
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Razib Khan has tangentially referenced Ralph and Coop et al in a discussion of Italian genetics.
See:
https://www.gnxp.com/WordPress/2018...s-gone/?utm_source=dlvr.it&utm_medium=twitter
"This is on my mind because on the episode of The Insight recorded with Patrick Wyman (it will probably drop in June) we talked extensively about Roman demography. And one of the peculiarities of 2013’s The Geography of Recent Genetic Ancestry across Europe is that Italy has a lot of deep population structure. From the paper:
"There is relatively little common ancestry shared between the Italian peninsula and other locations, and what there is seems to derive mostly from longer ago than 2,500 ya. An exception is that Italy and the neighboring Balkan populations share small but significant numbers of common ancestors in the last 1,500 years, as seen in Figures S16 and S17. The rate of genetic common ancestry between pairs of Italian individuals seems to have been fairly constant for the past 2,500 years, which combined with significant structure within Italy suggests a constant exchange of migrants between coherent subpopulations.""
"The implication here is that there’s population structure deeper than the Roman period. When I first saw these results I was surprised. Looking at genome-wide data I was pretty sure that most of the modern Italian population dated to the Roman Republican period, but I was not expecting provincial level substructure. It was like telling me that the Samnites and Umbrians were still with us!
But what about the great cosmopolitan cities of Neopolis, Rome, and Ravenna? Some commenters on this blog routinely get frustrated when I dismiss the textual and epigraphic evidence of massive migration into the Italian peninsula during the height of the Roman Empire. Actually, I believe that this migration occurred. I just do not believe it was particularly impactful genetically today. Though my general outlook on this issue goes back over ten years (in part thanks to the suggestion of Greg Cochran), I believe the issue here is that cities are such incredible demographic sinks.
Roman urban cosmopolitanism was parasitic on migration. Demographically it was never self-sustaining. In fact, as Patrick points out urban areas probably did not see sustained above replacement reproduction anywhere in the world before about 1900, with the emergence of germ theory and massive public sanitation works, especially in the United States. This is evident in books as diverse as Kyle Harper’s The Fate of Rome and The Rise and Fall of American Growth."
Perhaps an analogy would be what if all the major cities in the U.S. were bombed to smithereens, and the population of the future was descended from the people of small town and rural America?
Another factor might be that they probably all didn't stay even in the cities for multi-generations, and that most of the slave population experienced drastic "culling" at relatively young ages.
We've discussed Ralph and Coop extensively in other threads. Just use the search engine.
The paper itself:
http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1001555
See:
https://www.gnxp.com/WordPress/2018...s-gone/?utm_source=dlvr.it&utm_medium=twitter
"This is on my mind because on the episode of The Insight recorded with Patrick Wyman (it will probably drop in June) we talked extensively about Roman demography. And one of the peculiarities of 2013’s The Geography of Recent Genetic Ancestry across Europe is that Italy has a lot of deep population structure. From the paper:
"There is relatively little common ancestry shared between the Italian peninsula and other locations, and what there is seems to derive mostly from longer ago than 2,500 ya. An exception is that Italy and the neighboring Balkan populations share small but significant numbers of common ancestors in the last 1,500 years, as seen in Figures S16 and S17. The rate of genetic common ancestry between pairs of Italian individuals seems to have been fairly constant for the past 2,500 years, which combined with significant structure within Italy suggests a constant exchange of migrants between coherent subpopulations.""
"The implication here is that there’s population structure deeper than the Roman period. When I first saw these results I was surprised. Looking at genome-wide data I was pretty sure that most of the modern Italian population dated to the Roman Republican period, but I was not expecting provincial level substructure. It was like telling me that the Samnites and Umbrians were still with us!
But what about the great cosmopolitan cities of Neopolis, Rome, and Ravenna? Some commenters on this blog routinely get frustrated when I dismiss the textual and epigraphic evidence of massive migration into the Italian peninsula during the height of the Roman Empire. Actually, I believe that this migration occurred. I just do not believe it was particularly impactful genetically today. Though my general outlook on this issue goes back over ten years (in part thanks to the suggestion of Greg Cochran), I believe the issue here is that cities are such incredible demographic sinks.
Roman urban cosmopolitanism was parasitic on migration. Demographically it was never self-sustaining. In fact, as Patrick points out urban areas probably did not see sustained above replacement reproduction anywhere in the world before about 1900, with the emergence of germ theory and massive public sanitation works, especially in the United States. This is evident in books as diverse as Kyle Harper’s The Fate of Rome and The Rise and Fall of American Growth."
Perhaps an analogy would be what if all the major cities in the U.S. were bombed to smithereens, and the population of the future was descended from the people of small town and rural America?
Another factor might be that they probably all didn't stay even in the cities for multi-generations, and that most of the slave population experienced drastic "culling" at relatively young ages.
We've discussed Ralph and Coop extensively in other threads. Just use the search engine.
The paper itself:
http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1001555
