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Thread: New paper on Basal Eurasian

  1. #1
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    3 out of 3 members found this post helpful.

    New paper on Basal Eurasian

    See: John A. Kamm et al
    "Efficiently inferring the demographic history of many populations with allele count data"

    https://www.biorxiv.org/content/early/2018/03/23/287268

    These researchers introduce a new method which they say shows that Basal Eurasian split off 80,000 years ago, and estimate the amount in European farmers as 9.3%.

    "The sample frequency spectrum (SFS), or histogram of allele counts, is an important summary statistic in evolutionary biology, and is often used to infer the history of population size changes, migrations, and other demographic events affecting a set of populations. The expected multipopulation SFS under a given demographic model can be efficiently computed when the populations in the model are related by a tree, scaling to hundreds of populations. Admixture, back-migration, and introgression are common natural processes that violate the assumption of a tree-like population history, however, and until now the expected SFS could be computed for only a handful of populations when the demographic history is not a tree. In this article, we present a new method for efficiently computing the expected SFS and linear functionals of it, for demographies described by general directed acyclic graphs. This method can scale to more populations than previously possible for complex demographic histories including admixture. We apply our method to an 8-population SFS to estimate the timing and strength of a proposed "basal Eurasian" admixture event in human history. We implement and release our method in a new open-source software package momi2."

    Lazaridis announced the paper on his twitter account and made the following comments:

    "
    A quick comment is that in Lazaridis et al. (2016) we present updated Basal Eurasian estimates for European farmers (Europe_EN) which is 23.9+/-3.8% (Table S4.9) which is closer to the 9.4% of the preprint than the original estimate for Stuttgart in the 2014 paper "

    "Also, this estimate is subject to biases depending on whether EEF is really a mixture of just Basal Eurasian + WHG or it has additional non-Basal components (some of this is discussed in SI4). So, I don't feel strongly about the 23.9% number3/"

    "But I'm heartened by the fact that there's a new line of evidence for the actual existence of a Basal Eurasian population that did not experience Neandertal admixture!"

    "Might be worth putting Kostenki 14 and/or Sunghir3 in the model. For qpAdm/F4-ratio based methods in 2016 it was K14 that gave most information as it is no the West Eurasian lineage but more distantly related to Near Easterners than WHG is.end+1/"

    https://twitter.com/iosif_lazaridis

    I'll let the statisticians duke it out.



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    1 out of 1 members found this post helpful.
    I guess that puts doubts to rest regarding Basal Eurasian's existence.

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    I think I can not make links please search google on persian gulf during ice age.

    What arguments are there for the basal eurasians not to be this population, which perhaps even reduced to slavery by the already settled populations where they sought refuge in Iran, Levante and Egypt (archaic agriculture and grinding require a lot of labor and are very painful), saw their chromosomes replaced (or almost replaced) by those of the dominant population, as is normally the case for disadvantaged populations.The origin of agriculture in the Persian Gulf with a radiation to the Levant independent of radiation to Iran may explain both having the same domesticated seeds and agriculture without mixing their genes .This population may also help explain some of the questions that still remain about the initial diversification of human haplogroups.

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