Angela
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Razib Khan has a good blog post on the paper:
The Canaanites walk among us:
https://gnxp.nofe.me/2017/05/26/the-canaanites-walk-among-us/
"The admixture plot above reflects the five individuals from Sidon dating to about ~1750 BCE. They are about a 50:50 mix of western and eastern farmer. Though they seem to be genetically rather similar to modern Lebanese (the authors sampled Lebanese Christians in particular), there have been some changes between the Bronze Age and the modern period. In particular, a genetic component that seems to be related to the Eurasian steppe is present in modern Lebanese. Explicit admixture estimates give a range of 5-10% mixing into a ~90-95% Bronze Age ancestral background."
"Though looking at Muslim populations one can see minor and non-trivial contributions of populations which moved in after Islam (Sub-Saharan and East Asia segments are clear signs of slavery impacting Muslims that would not apply to ethno-religious minorities), most of the ancestry broadly is deeply rooted back to antiquity."
"Because of sampling issues one can’t estimate admixture between eastern and western farmers just from looking at ancient DNA transects. We don’t have the density that we have in Europe (yet). So the authors used a more classic inference technique looking at decays of linkage disequilibrium in the genome. In short you can see how many generations that a pulse admixture between two populations occurred by looking at correlations of variants across the genome. The authors arrive at the intervals above, and in particular focus on the period that seems to overlap with the rise and fall of the empire of Sargon of Akkad and correlated with a climatic disruption."
"I suspect they are wrong here. First, it seems pretty clear to me that LD based admixtures assuming a pulse event have a bias toward underestimating values. There are theoretical reasons for this. So usually I pad the mid-point value across the interval on these estimates."
" I believe that the massive western-eastern farmer admixture occurred between 3600 and 3100 BCE, during the Uruk Expansion. The evidence of lower Mesopotamian influence and demographic settlement in places as far afield as Anatolia, the Caucasus, and Syria, are well attested from the archaeology of this period. This was was a time when a very complex and sophisticated civilization emerged almost de novo across much of the Near East. I believe that a prehistoric expansion of Sumerian civilization mediated the merging of eastern and western farmers, though some of the mixing pre-dates and post-dates the Uruk Expansion and collapse (e.g., the movement of western farmer ancestry into Mesopotamia seems certain to have occurred through the arrival of groups like the Amorites)."
"What about the second ancestral component? Drilling down on the Y chromosomes of the Levant, R1b seems to far outnumber R1a, though the R1a clades are all of the Asian/Scythian Z-93 branch which is dominant in Central Asia and the Levant. The R1a may have come with the Persians, but in region of the western Levant for several hundred years after the period of the Bronze Age Sidon samples there was a state, the Mitanni, which clearly had an Indo-Aryan ruling class.An Aegean influence occurred multiple times. First, at the end of the Bronze Age many of the “Sea Peoples” were clearly of Aegean origin, and so may have brought steppe-like ancestry. Second, there was the long period under Hellenistic and Roman rule, when Greek and non-Greek ethnic identity existed side by side, and movement occurred in both directions. I think only ancient DNA will answer this question, and it may be that there were multiple post-Bronze Age inputs of genes which shaped modern Levantines."
The Canaanites walk among us:
https://gnxp.nofe.me/2017/05/26/the-canaanites-walk-among-us/
"The admixture plot above reflects the five individuals from Sidon dating to about ~1750 BCE. They are about a 50:50 mix of western and eastern farmer. Though they seem to be genetically rather similar to modern Lebanese (the authors sampled Lebanese Christians in particular), there have been some changes between the Bronze Age and the modern period. In particular, a genetic component that seems to be related to the Eurasian steppe is present in modern Lebanese. Explicit admixture estimates give a range of 5-10% mixing into a ~90-95% Bronze Age ancestral background."
"Though looking at Muslim populations one can see minor and non-trivial contributions of populations which moved in after Islam (Sub-Saharan and East Asia segments are clear signs of slavery impacting Muslims that would not apply to ethno-religious minorities), most of the ancestry broadly is deeply rooted back to antiquity."
"Because of sampling issues one can’t estimate admixture between eastern and western farmers just from looking at ancient DNA transects. We don’t have the density that we have in Europe (yet). So the authors used a more classic inference technique looking at decays of linkage disequilibrium in the genome. In short you can see how many generations that a pulse admixture between two populations occurred by looking at correlations of variants across the genome. The authors arrive at the intervals above, and in particular focus on the period that seems to overlap with the rise and fall of the empire of Sargon of Akkad and correlated with a climatic disruption."
"I suspect they are wrong here. First, it seems pretty clear to me that LD based admixtures assuming a pulse event have a bias toward underestimating values. There are theoretical reasons for this. So usually I pad the mid-point value across the interval on these estimates."
" I believe that the massive western-eastern farmer admixture occurred between 3600 and 3100 BCE, during the Uruk Expansion. The evidence of lower Mesopotamian influence and demographic settlement in places as far afield as Anatolia, the Caucasus, and Syria, are well attested from the archaeology of this period. This was was a time when a very complex and sophisticated civilization emerged almost de novo across much of the Near East. I believe that a prehistoric expansion of Sumerian civilization mediated the merging of eastern and western farmers, though some of the mixing pre-dates and post-dates the Uruk Expansion and collapse (e.g., the movement of western farmer ancestry into Mesopotamia seems certain to have occurred through the arrival of groups like the Amorites)."
"What about the second ancestral component? Drilling down on the Y chromosomes of the Levant, R1b seems to far outnumber R1a, though the R1a clades are all of the Asian/Scythian Z-93 branch which is dominant in Central Asia and the Levant. The R1a may have come with the Persians, but in region of the western Levant for several hundred years after the period of the Bronze Age Sidon samples there was a state, the Mitanni, which clearly had an Indo-Aryan ruling class.An Aegean influence occurred multiple times. First, at the end of the Bronze Age many of the “Sea Peoples” were clearly of Aegean origin, and so may have brought steppe-like ancestry. Second, there was the long period under Hellenistic and Roman rule, when Greek and non-Greek ethnic identity existed side by side, and movement occurred in both directions. I think only ancient DNA will answer this question, and it may be that there were multiple post-Bronze Age inputs of genes which shaped modern Levantines."