sstar: A Python package for detecting archaic introgression from population genetic data with S*

Abstract

S* is a widely used statistic for detecting archaic admixture from population genetic data. To apply S*, several previous studies used the freezing-archer repository, which is a compilation of Python 2 and R scripts originally developed to detect Neanderthal and Denisovan introgression into modern humans. When studying other species or populations, however, freezing-archer is not directly applicable. Here, we implemented a new Python 3 package named sstar, with better performance than freezing-archer. Reliability was also improved after fixing bugs in freezing-archer. Compared with freezing-archer, sstar is more user-friendly, versatile, and well-documented.