1 | INTRODUCTION
Hybridization between species and admixture between populations are powerful mechanisms influencing biological evolution. Genetic admixture patterns have thus been extensively studied to reconstruct past population migrations and understand admixture-related adaptation such as heterosis or post-admixture selection (Brandenburg et al., 2017; Hellenthal et al., 2014; Skoglund, Ersmark, Palkopoulou, & Dalen, 2015).
A long history of statistical developments in population genetics provided tools to identify and describe admixture patterns from genetic data (Bernstein, 1931; Cavalli-Sforza & Bodmer, 1971; Chakraborty & Weiss, 1988; Long 1991; Falush, Stephens, & Pritchard, 2003; Patterson et al., 2012), They enabled inferring the ancestral origins of admixed populations or investigate adaptive introgression in numerous species (e.g. Martin et al., 2013; Patin et al., 2017; Stryjewski & Sorenson, 2017).