title: Genetic structure characterization of Chileans reflects historical immigration patterns.
abstract: Identifying the ancestral components of genomes of admixed individuals helps uncovering the genetic basis of diseases and understanding the demographic history of populations. We estimate local ancestry on 313 Chileans and assess the contribution from three continental populations. The distribution of ancestry block-length suggests an average admixing time around 10 generations ago. Sex-chromosome analyses confirm imbalanced contribution of European men and Native-American women. Previously known genes under selection contain SNPs showing large difference in allele frequencies. Furthermore, we show that assessing ancestry is harder at SNPs with higher recombination rates and easier at SNPs with large difference in allele frequencies at the ancestral populations. Two observations, that African ancestry proportions systematically decrease from North to South, and that European ancestry proportions are highest in central regions, show that the genetic structure of Chileans is under the influence of a diffusion process leading to an ancestry gradient related to geography.
authors.affiliation: Department of Statistics, Facultad de Matemáticas, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago 6904411, Chile.
authors.forename: Susana
authors.identifier: 0000000347239660
authors.initials: S
authors.lastname: Eyheramendy
authors.affiliation: Interdisciplinary Center for Intercultural and Indigenous Studies, Anthropology Program, Institute of Sociology, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago 6904411, Chile.
authors.forename: Felipe I
authors.identifier: 0000000306504448
authors.initials: FI
authors.lastname: Martinez
authors.affiliation: Department of Statistics, Facultad de Matemáticas, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago 6904411, Chile.
authors.forename: Federico
authors.initials: F
authors.lastname: Manevy
authors.affiliation: 1] Center for Genetics and Genomics, Facultad de Medicina, Clinica Alemana, Universidad del Desarrollo, Av. Las Condes 12438, Lo Barnechea, Santiago 7710162, Chile [2] Hantavirus Program, Facultad de Medicina, Clinica Alemana Universidad del Desarrollo, Las Condes 12438, Lo Barnechea, Santiago 7710162, Chile.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Vial
authors.affiliation: Center for Genetics and Genomics, Facultad de Medicina, Clinica Alemana, Universidad del Desarrollo, Av. Las Condes 12438, Lo Barnechea, Santiago 7710162, Chile.
authors.forename: Gabriela M
authors.initials: GM
authors.lastname: Repetto
mesh_terms: D044383:Black People; D002677:Chile; D016000:Cluster Analysis; D004641:Emigration and Immigration; D005006:Ethnicity; D005060:Europe; D005260:Female; D005787:Gene Frequency; D005828:Genetics, Population; D015894:Genome, Human; D005838:Genotype; D005843:Geography; D006239:Haplotypes; D006801:Humans; D007198:Indians, North American; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D020641:Polymorphism, Single Nucleotide; D012737:Sex Factors; D012984:Software; D044465:White People