03-16-2024, 03:49 PM
In this thread we discuss Basal Eurasians.
Summary for those who are unfamiliar with the topic:
East Eurasians have higher Neanderthal ancestry than West Eurasians. Three hypotheses have been proposed to explain the difference:
1) Greater West Eurasian population size led to stronger purifying selection against Neanderthal ancestry.
2) East Eurasians received additional Neanderthal admixture after the initial admixture event between Main Eurasians and Neanderthals.
3) Neanderthal ancestry was diluted in West Eurasians by admixture from a hypothetical, deeply divergent "Basal Eurasian" ghost population with no Neanderthal ancestry.
Basal Eurasians are theorized to have split from other Eurasians 60-100kya before Main Eurasians mixed with Neanderthals in the Near East. They may have lived somewhere in North Africa or the Near East, most likely the Arabian peninsula which aligns with proposed Out of Africa migration routes.
Basal Eurasian ancestry varies by region in the ancient Near East: Caucasus_UP 24%, Anatolia_N 30%, Iran_N 45%, Natufian 50%. Ancient North African Iberomaurusians show high levels of Basal Eurasian ancestry and have been described as "the best ancient proxy for the basal Eurasian population group" (Ferreira 2021). Among modern West Eurasians, Basal Eurasian ancestry peaks among Arabians (40-45%), followed by Iranians (38%), Levantines (32%), Caucasians (20-25%), and is lowest among Europeans (<20%).
Some people have proposed that Basal Eurasians did not exist and the simplest explanation is that ancient Near Easterners harbor additional admixture from Sub-Saharan Africans. However, Lazaridis 2016 found no evidence for SSA admixture in Natufians.
Studies and figures:
Ancient human genomes suggest three ancestral populations for present-day Europeans, Lazaridis 2014
Genomic insights into the origin of farming in the ancient Near East, Lazaridis 2016
Parallel paleogenomic transects reveal complex genetic history of early European farmers, Lipson 2017
Projecting Ancient Ancestry in Modern-Day Arabians and Iranians: A Key Role of the Past Exposed Arabo-Persian Gulf on Human Migrations, Ferreira 2021
Efficiently inferring the demographic history of many populations with allele count data, Kamm 2021
Population genomics of post-glacial western Eurasia, Allentoft 2024
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![[Image: YQFXNYY.png]](https://i.imgur.com/YQFXNYY.png)
![[Image: RtyAuCo.jpeg]](https://i.imgur.com/RtyAuCo.jpeg)
![[Image: q5f97cY.jpeg]](https://i.imgur.com/q5f97cY.jpeg)
Summary for those who are unfamiliar with the topic:
East Eurasians have higher Neanderthal ancestry than West Eurasians. Three hypotheses have been proposed to explain the difference:
1) Greater West Eurasian population size led to stronger purifying selection against Neanderthal ancestry.
2) East Eurasians received additional Neanderthal admixture after the initial admixture event between Main Eurasians and Neanderthals.
3) Neanderthal ancestry was diluted in West Eurasians by admixture from a hypothetical, deeply divergent "Basal Eurasian" ghost population with no Neanderthal ancestry.
Basal Eurasians are theorized to have split from other Eurasians 60-100kya before Main Eurasians mixed with Neanderthals in the Near East. They may have lived somewhere in North Africa or the Near East, most likely the Arabian peninsula which aligns with proposed Out of Africa migration routes.
Basal Eurasian ancestry varies by region in the ancient Near East: Caucasus_UP 24%, Anatolia_N 30%, Iran_N 45%, Natufian 50%. Ancient North African Iberomaurusians show high levels of Basal Eurasian ancestry and have been described as "the best ancient proxy for the basal Eurasian population group" (Ferreira 2021). Among modern West Eurasians, Basal Eurasian ancestry peaks among Arabians (40-45%), followed by Iranians (38%), Levantines (32%), Caucasians (20-25%), and is lowest among Europeans (<20%).
Some people have proposed that Basal Eurasians did not exist and the simplest explanation is that ancient Near Easterners harbor additional admixture from Sub-Saharan Africans. However, Lazaridis 2016 found no evidence for SSA admixture in Natufians.
Studies and figures:
Ancient human genomes suggest three ancestral populations for present-day Europeans, Lazaridis 2014
Genomic insights into the origin of farming in the ancient Near East, Lazaridis 2016
Parallel paleogenomic transects reveal complex genetic history of early European farmers, Lipson 2017
Projecting Ancient Ancestry in Modern-Day Arabians and Iranians: A Key Role of the Past Exposed Arabo-Persian Gulf on Human Migrations, Ferreira 2021
Efficiently inferring the demographic history of many populations with allele count data, Kamm 2021
Population genomics of post-glacial western Eurasia, Allentoft 2024