Much more detail about African genomes and the discovery of a migration
October 30, 2020 10:30 AM Subscribe
An analysis of the genomes of people from 50 ethnolinguistic groups in Africa spots 62 genes under positive selection and 3 million more genetic variants than previously documented.
"The research team performed whole-genome sequencing analyses of 426 individuals that represent 50 ethnolinguistic groups, including previously unsampled populations, to explore the breadth of genomic diversity across Africa."
"In terms of population genetics, we discovered a migration that was never known. It was a trans-Sahelian migration that moved into central Nigeria. The timing of the migration into Nigeria didn’t correspond to any of the previous known migrations. We also kind of identified the root of the Bantu migration to southern Africa—that’s a very hotly debated topic not only in genetics, but also in linguistics."
"One of the really important things to convey is that this was work done in Africa by Africans. We collaborated with individual groups that are in the US or the UK, but this [study] is really rooted in Africa."
"The research team performed whole-genome sequencing analyses of 426 individuals that represent 50 ethnolinguistic groups, including previously unsampled populations, to explore the breadth of genomic diversity across Africa."
"In terms of population genetics, we discovered a migration that was never known. It was a trans-Sahelian migration that moved into central Nigeria. The timing of the migration into Nigeria didn’t correspond to any of the previous known migrations. We also kind of identified the root of the Bantu migration to southern Africa—that’s a very hotly debated topic not only in genetics, but also in linguistics."
"One of the really important things to convey is that this was work done in Africa by Africans. We collaborated with individual groups that are in the US or the UK, but this [study] is really rooted in Africa."
I wonder how long until any of this ends up in ancestry genome tests. My brother sent off a sample to see if he could find anything out about his father, and of course all he got back was a very vague "West African". But with 3 million new variants to test for I assume that could be narrowed down quite a bit, as with the over-represented European SNPs in current tests.
It isn't just the SNPs that inform whether you get a broad "West African" or something more specific like "Cote d'Ivoire", it's relative SNP frequencies when compared to reference populations, and Africans are very underrepresented when compared to Europeans in those datasets. For instance, 23andMe's reference dataset for Europeans consists of 6350 individuals; for sub-Saharan Africa, which has far greater genetic diversity than Europe* , it's only 1991.
*there are sub-Saharan African populations that are more genetically distinct from each other than the average African is from the average European.
posted by Pseudonymous Cognomen at 11:26 AM on October 30, 2020 [10 favorites]
It isn't just the SNPs that inform whether you get a broad "West African" or something more specific like "Cote d'Ivoire", it's relative SNP frequencies when compared to reference populations, and Africans are very underrepresented when compared to Europeans in those datasets. For instance, 23andMe's reference dataset for Europeans consists of 6350 individuals; for sub-Saharan Africa, which has far greater genetic diversity than Europe* , it's only 1991.
*there are sub-Saharan African populations that are more genetically distinct from each other than the average African is from the average European.
posted by Pseudonymous Cognomen at 11:26 AM on October 30, 2020 [10 favorites]
I general this makes sense, humans outside Africa have gone through several genetic bottlenecks - we should expect African DNA to be more varied - to in general have a wider bell curve - we should expect faster (and slower) runners , taller (and shorter) extremes in the population, and yes, a smarter, more intelligent end to the bell curve too.
I'm kind of amazed there aren't people trolling Africa looking for those geniuses that must be there - likely it's racism, or white people's belief in the superiority of their neanderthal genes .... of maybe Wakanda got there first ....
posted by mbo at 4:50 PM on October 30, 2020 [2 favorites]
I'm kind of amazed there aren't people trolling Africa looking for those geniuses that must be there - likely it's racism, or white people's belief in the superiority of their neanderthal genes .... of maybe Wakanda got there first ....
posted by mbo at 4:50 PM on October 30, 2020 [2 favorites]
mbo: to in general have a wider bell curve - we should expect faster (and slower) runners , taller (and shorter) extremes in the population, and yes, a smarter, more intelligent end to the bell curve too.
There are people who argue that "wider bell curve" is the reason that there are so many more men in jobs - like working as an engineer for Google - which require "genius". They never seem to extend that reasoning to think about the racial balance at Google, though. Somehow they lack the imagination to picture a meritocratic world that's any different from what we've got now.
posted by clawsoon at 5:50 PM on October 30, 2020 [2 favorites]
There are people who argue that "wider bell curve" is the reason that there are so many more men in jobs - like working as an engineer for Google - which require "genius". They never seem to extend that reasoning to think about the racial balance at Google, though. Somehow they lack the imagination to picture a meritocratic world that's any different from what we've got now.
posted by clawsoon at 5:50 PM on October 30, 2020 [2 favorites]
Just for the record I'm not suggesting that somehow women have gone through some genetic bottleneck event but not men .....
(and you should take my first posting above largely as a gentle dig at any concept of white superiority)
posted by mbo at 5:59 PM on October 30, 2020 [3 favorites]
(and you should take my first posting above largely as a gentle dig at any concept of white superiority)
posted by mbo at 5:59 PM on October 30, 2020 [3 favorites]
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posted by clawsoon at 10:54 AM on October 30, 2020