An explanation for the sister repulsion phenomenon in Patterson's f-statistics.

Autor:	Atağ G; Department of Biological Sciences, Middle East Technical University, Ankara 06800, Turkey.; Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig 04103, Germany., Waldman S; Department of Human Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA., Carmi S; Braun School of Public Health and Community Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel., Somel M; Department of Biological Sciences, Middle East Technical University, Ankara 06800, Turkey.
Jazyk:	angličtina
Zdroj:	Genetics [Genetics] 2024 Nov 06; Vol. 228 (3).
DOI:	10.1093/genetics/iyae144
Abstrakt:	Patterson's f-statistics are among the most heavily utilized tools for analyzing genome-wide allele frequency data for demographic inference. Beyond studying admixture, f3- and f4-statistics are also used for clustering populations to identify groups with similar histories. However, previous studies have noted an unexpected behavior of f-statistics: multiple populations from a certain region systematically show higher genetic affinity to a more distant population than to their neighbors, a pattern that is mismatched with alternative measures of genetic similarity. We call this counter-intuitive pattern "sister repulsion". We first present a novel instance of sister repulsion, where genomes from Bronze Age East Anatolian sites show higher affinity toward Bronze Age Greece rather than each other. This is observed both using f3- and f4-statistics, contrasts with archaeological/historical expectation, and also contradicts genetic affinity patterns captured using principal components analysis or multidimensional scaling on genetic distances. We then propose a simple demographic model to explain this pattern, where sister populations receive gene flow from a genetically distant source. We calculate f3- and f4-statistics using simulated genetic data with varying population genetic parameters, confirming that low-level gene flow from an external source into populations from 1 region can create sister repulsion in f-statistics. Unidirectional gene flow between the studied regions (without an external source) can likewise create repulsion. Meanwhile, similar to our empirical observations, multidimensional scaling analyses of genetic distances still cluster sister populations together. Overall, our results highlight the impact of low-level admixture events when inferring demographic history using f-statistics. Competing Interests: Conflicts of interest The author(s) declare no conflicts of interest. (© The Author(s) 2024. Published by Oxford University Press on behalf of The Genetics Society of America.)
Databáze:	MEDLINE
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