title : Ancient DNA from ancient Canarian Islanders illuminates the prehistory of North Africa and evidences the effects of insularity on human populations.
Abstract :
quote:The indigenous population of the Canary Islands, which colonized the archipelago around the 3rd century CE, provides both a window into the past of North Africa and a unique model to explore the effects of insularity. We generated genome-wide data from 40 samples from the seven islands, dated between the 3rd – 16th centuries CE. Along with components already present in Moroccan Neolithic populations, the Canarian natives show signatures related to Bronze Age expansions in Eurasia and trans-Saharan migrations. The lack of gene flow between islands and constant or decreasing effective population sizes suggest that populations were isolated. While some island populations maintained relatively high genetic diversity, with the only detected bottleneck coinciding with the colonization time, other islands with fewer natural resources show the effects of insularity and isolation. Finally, consistent genetic differentiation between eastern and western islands points to a more complex colonization process than previously thought.
Here I made the average of all those samples and here are the 25 closest populations :
Here with a more precise set of samples :
As we can observe, they are similar to modern North Africans. What I find intriguing is that the western islands exhibit samples with a more IBM-shifted ancestry, aligning with the data I've read in recent years. This research described the remains from those islands as more robust/cromagnoid. On the other hand, the eastern islands appear to have been more influenced by a gracile population that settled there during the early 1st century AD which would explain the higher steppe and EEF input.
Posts: 1779 | From: Somewhere In the Rif Mountains | Registered: Nov 2021
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What's your thoughts on how they compare to the previously published Guanches?
Posts: 1781 | From: New York | Registered: Jul 2016
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quote:Originally posted by Elmaestro: What's your thoughts on how they compare to the previously published Guanches?
I don't see many differences, and both sets show the variations I highlighted above. What's interesting here is that the study is more extensive, and we obtained samples from all the islands. Consequently, we discovered new HGs that were not reported in previous works, if I remember correctly, such as E-m44 and T-L131.
What's your thoughts on it ?
Posts: 1779 | From: Somewhere In the Rif Mountains | Registered: Nov 2021
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posted
There's no surprises. These results are more comprehensive though would have been more revealing probably 5-8 years ago. Seeing these samples are pretty much fixed for African paternal uniparentals while European Maternal haplogroups dominate is something we were expecting before. However the previous study had them dominated by African MtHGs which was only talked about briefly. The dominance of M81 is also consistent with the ideas behind the wave-like dispersal of Berber haplogroups. The time period and Haplogroup pattern supports the reconstruction of such dispersal since the fall of Carthage and further evidenced by the refined script found on the island around these dates tracing origin to Masaesyli.
The West-Central African Haplogroups which pop up here and there will likely only be resolved with more relevant aDNA. It's not a surprise they're there. We just wanna know how it got there and why they're divorced from Autosomal signatures. I've been waiting for clarity about this for about a decade. This study likely wont provide it so it's almost irrelevant. m44 we should know will eventually be found North Africa because E1a does pop up in Europe divorced from African Autosomal signatures. T-L131 likely came from a Saharan source but it'll be insightful to know when.
Posts: 1781 | From: New York | Registered: Jul 2016
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quote:Originally posted by Elmaestro: There's no surprises. These results are more comprehensive though would have been more revealing probably 5-8 years ago. Seeing these samples are pretty much fixed for African paternal uniparentals while European Maternal haplogroups dominate is something we were expecting before. However the previous study had them dominated by African MtHGs which was only talked about briefly. The dominance of M81 is also consistent with the ideas behind the wave-like dispersal of Berber haplogroups. The time period and Haplogroup pattern supports the reconstruction of such dispersal since the fall of Carthage and further evidenced by the refined script found on the island around these dates tracing origin to Masaesyli.
The West-Central African Haplogroups which pop up here and there will likely only be resolved with more relevant aDNA. It's not a surprise they're there. We just wanna know how it got there and why they're divorced from Autosomal signatures. I've been waiting for clarity about this for about a decade. This study likely wont provide it so it's almost irrelevant. m44 we should know will eventually be found North Africa because E1a does pop up in Europe divorced from African Autosomal signatures. T-L131 likely came from a Saharan source but it'll be insightful to know when.
Even though it seems the islands received an influx of settlers around the early 1st century AD, the initial colonization predates the collapse of Carthage by centuries. I wonder if paternal haplogroups like R1b offer clues to this and whether they indicate a more diverse haplogroup landscape before the expansion of E-m81 which would be in line with what we know about Bronze Age/early Iron Age NW Africa.
Posts: 1779 | From: Somewhere In the Rif Mountains | Registered: Nov 2021
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interestingly, the paper concludes that modern north africans have higher SSA and Near eastern ancestry compared to Guanches.
quote: Modern North Africans exhibit a lower proportion of the ancient North African component when compared to the Canarian natives in an unsupervised admixture analysis, decreasing from the west towards the eastern areas (Fig. 2b). As expected from historical records, North Africans have differences correlating to additional migration waves reaching this region in the last two millennia, including a higher Near Eastern contribution likely due to the Arab expansion (shown in grey) and a higher Sub-Saharan African one due to trans-Saharan migrations (red), most probably related to the slave trade and commercial interactions.
Does the better modeling with Mota imply that their SSA component was more East african-like like the older NA samples ?
Posts: 1779 | From: Somewhere In the Rif Mountains | Registered: Nov 2021
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Mota is used in the article as a proxy source of sub-Saharan ancestry. There is nothing in the PCA that distinguishes Sub-Saharan into East, Central or Western Sub-Saharans
I am also noticing here one of those dots is way out by itself behind the text of "Western European"
Geneticists have a problem now how to plot horn/East Africans Africans in light of the discovery of Mota man and his DNA They are not on the list, except for Mota
Posts: 42919 | From: , | Registered: Jan 2010
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The Peopling of the Canary Islands by Roger Blench (English Version)
-------------------- It's not my burden to disabuse the ignorant of their wrong opinions Posts: 2699 | From: New York | Registered: Jun 2015
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