“…To reveal latent population structure within the craniometric dataset and to produce the individual posterior probabilities, or coefficients of membership, needed to estimate admixture proportions and infer geographic ancestry in the absence of population identifiers and reference samples, this study exploits the unsupervised model-based clustering methods (MBC) of finite mixture analysis (FMA). Finite mixture models are powerful tools for probabilistic data analysis as they provide a principled, yet flexible, framework for the robust clustering of various distributions and at all levels of supervision (Ganesalingam and McLachlan, 1978;Banfield and Raftery, 1993;Schroeter et al, 1998;McLachlan and Peel, 2000;Peel and McLachlan, 2000). Here, it is assumed that the data is composed of a mixture of a finite number of underlying Gaussian probability distributions, with each component in the model corresponding directly some number of unobserved clusters or populations, k, which may be mutually exclusive or exhibit varying degrees of overlap Fraley and Raftery, 2002).…”