Reply To Lazaridis And Reich: Robust Model-Based Inference Of Male-Biased Admixture During Bronze Age Migration From The Pontic-Caspian Steppe

Abstract

Comparing the sex-specifically inherited X chromosome to the autosomes in ancient genetic samples, we (1) studied sex-specific admixture for two prehistoric migrations. For each migration, we used several admixture estimation procedures--including ADMIXTURE model-based clustering (2)--comparing X-chromosomal and autosomal ancestry in contemporaneous Central Europeans, and interpreting greater admixture from the migrating population on the autosomes as male-biased migration. For migration into late Neolithic/Bronze Age Central Europeans (\"BA\") from the Pontic-Caspian steppe (\"SP\"), we inferred male-biased admixture at 5-14 males per migrating female.\n\nLazaridis & Reich (3) contest this male-biased migration claim. For simulated individuals, they claim that ADMIXTURE provides biased X-chromosomal ancestry estimates. They argue that if the bias is taken into account, the ...