title: Bayesian inferences suggest that Amazon Yunga Natives diverged from Andeans less than 5000 ybp: implications for South American prehistory.
abstract: BACKGROUND
  Archaeology reports millenary cultural contacts between Peruvian Coast-Andes and the Amazon Yunga, a rainforest transitional region between Andes and Lower Amazonia. To clarify the relationships between cultural and biological evolution of these populations, in particular between Amazon Yungas and Andeans, we used DNA-sequence data, a model-based Bayesian approach and several statistical validations to infer a set of demographic parameters.
  
  
  RESULTS
  We found that the genetic diversity of the Shimaa (an Amazon Yunga population) is a subset of that of Quechuas from Central-Andes. Using the Isolation-with-Migration population genetics model, we inferred that the Shimaa ancestors were a small subgroup that split less than 5300 years ago (after the development of complex societies) from an ancestral Andean population. After the split, the most plausible scenario compatible with our results is that the ancestors of Shimaas moved toward the Peruvian Amazon Yunga and incorporated the culture and language of some of their neighbors, but not a substantial amount of their genes. We validated our results using Approximate Bayesian Computations, posterior predictive tests and the analysis of pseudo-observed datasets.
  
  
  CONCLUSIONS
  We presented a case study in which model-based Bayesian approaches, combined with necessary statistical validations, shed light into the prehistoric demographic relationship between Andeans and a population from the Amazon Yunga. Our results offer a testable model for the peopling of this large transitional environmental region between the Andes and the Lower Amazonia. However, studies on larger samples and involving more populations of these regions are necessary to confirm if the predominant Andean biological origin of the Shimaas is the rule, and not the exception.
authors.forename: Marilia O
authors.initials: MO
authors.lastname: Scliar
authors.forename: Mateus H
authors.initials: MH
authors.lastname: Gouveia
authors.forename: Andrea
authors.initials: A
authors.lastname: Benazzo
authors.forename: Silvia
authors.initials: S
authors.lastname: Ghirotto
authors.forename: Nelson J R
authors.initials: NJ
authors.lastname: Fagundes
authors.forename: Thiago P
authors.initials: TP
authors.lastname: Leal
authors.forename: Wagner C S
authors.initials: WC
authors.lastname: Magalhães
authors.forename: Latife
authors.initials: L
authors.lastname: Pereira
authors.forename: Maira R
authors.initials: MR
authors.lastname: Rodrigues
authors.forename: Giordano B
authors.initials: GB
authors.lastname: Soares-Souza
authors.forename: Lilia
authors.initials: L
authors.lastname: Cabrera
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Berg
authors.forename: Robert H
authors.initials: RH
authors.lastname: Gilman
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bertorelle
authors.forename: Eduardo
authors.initials: E
authors.lastname: Tarazona-Santos
mesh_terms: D001499:Bayes Theorem; D005075:Biological Evolution; D014644:Genetic Variation; D005828:Genetics, Population; D063426:Human Migration; D006801:Humans; D007199:Indians, South American / Q000235:genetics*; D008969:Molecular Sequence Data; D044382:Population Groups; D013020:South America