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Thursday, 26 January 2023

Modeling the Neolithic ancestry of Modern and Ancient Europeans/West Asians using qpAdm, including ancient Greeks/Mycenaeans, Minoans, Hittites, Phoenicians, Yamnaya

Recent studies by Harvard utilized Autosomal DNA modeling techniques to analyze the genetic makeup of ancient populations, including the Cypriots, Mycenaeans, Minoans, and Levantines. However, the study did not include a analysis of modern populations. In order to make comparisons between ancient and modern populations, I personally used the same DNA modeling program to model modern populations with the DNA samples provided by Harvard.

Studies:
https://reich.hms.harvard.edu/sites/reich.hms.harvard.edu/files/inline-files/8_25_2022_Manuscript1_ChalcolithicBronzeAge.pdf
https://reich.hms.harvard.edu/sites/reich.hms.harvard.edu/files/inline-files/8_25_2022_Manuscript2_Neolithic.pdf

My models:

Neolithic Era ancestry

Mesolithic era ancestry
Same as above but in a chart:

I will update the models sometimes, i might add more populations or change a bit the reference populations.

What is qpAdm?

qpAdm is a statistical tool for studying the ancestry of populations with histories that involve admixture between two or more source populations. Using qpAdm, it is possible to identify plausible models of admixture that fit the population history of a group of interest and to calculate the relative proportion of ancestry that can be ascribed to each source population in the model. Although qpAdm is widely used in studies of population history of human (and nonhuman) groups

Study:

Assessing the performance of qpAdm: a statistical tool for studying population admixture

https://academic.oup.com/genetics/article/217/4/iyaa045/6070149

The theory underlying qpAdm, which was introduced in Haak et al. (2015), builds upon a class of statistics known as f-statistics (Patterson et al. 2012). f-statistics analyze patterns of allele frequency correlations among populations in order to determine whether their population histories can be described using strictly tree-based models, or if more complex models, such as those involving admixture, are required to explain the genetic data. f-statistics have been widely used in the population genetic literature and their behavior is well understood (Reich et al. 2009, 2012; Patterson et al. 2012; Peter 2016; Soraggi and Wiuf 2019; Lipson 2020). qpAdm harnesses the power of f-statistics to determine whether a population of interest (a target population) can be plausibly modeled as descending from a common ancestor of one or more source populations. For example, in a model with two source populations, qpAdm tests whether the target population is the product of a two-way admixture event between these source populations.

The method requires users to specify a list of target and source populations and a list of additional reference populations which provide information about the relationships among the target and source populations.

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