title: Population genetic structure of traditional populations in the Peruvian Central Andes and implications for South American population history.
abstract: Molecular-based characterizations of Andean peoples are traditionally conducted in the service of elucidating continent-level evolutionary processes in South America. Consequently, genetic variation among "western" Andean populations is often represented in relation to variation among "eastern" Amazon and Orinoco River Basin populations. This west-east contrast in patterns of population genetic variation is typically attributed to large-scale phenomena, such as dual founder colonization events or differing long-term microevolutionary histories. However, alternative explanations that consider the nature and causes of population genetic diversity within the Andean region remain underexplored. Here we examine population genetic diversity in the Peruvian Central Andes using data from the mtDNA first hypervariable region and Y-chromosome short tandem repeats among 17 newly sampled populations and 15 published samples. Using this geographically comprehensive data set, we first reassessed the currently accepted pattern of western versus eastern population genetic structure, which our results ultimately reject: mtDNA population diversities were lower, rather than higher, within Andean versus eastern populations, and only highland Y-chromosomes exhibited significantly higher within-population diversities compared with eastern groups. Multiple populations, including several highland samples, exhibited low genetic diversities for both genetic systems. Second, we explored whether the implementation of Inca state and Spanish colonial policies starting at about ad 1400 could have substantially restructured population genetic variation and consequently constitute a primary explanation for the extant pattern of population diversity in the Peruvian Central Andes. Our results suggest that Peruvian Central Andean population structure cannot be parsimoniously explained as the sole outcome of combined Inca and Spanish policies on the region's population demography: highland populations differed from coastal and lowland populations in mtDNA genetic structure only; highland groups also showed strong evidence of female-biased gene flow and/or effective sizes relative to other Peruvian ecozones. Taken together, these findings indicate that population genetic structure in the Peruvian Central Andes is considerably more complex than previously reported and that characterizations of and explanations for genetic variation may be best pursued within more localized regions and defined time periods.
authors.affiliation: 1 Department of Anthropology, University of Tennessee, Knoxville, Tennessee.
authors.forename: Graciela S
authors.initials: GS
authors.lastname: Cabana
authors.forename: Cecil M
authors.initials: CM
authors.lastname: Lewis
authors.forename: Raúl Y
authors.initials: RY
authors.lastname: Tito
authors.forename: R Alan
authors.initials: RA
authors.lastname: Covey
authors.forename: Angela M
authors.initials: AM
authors.lastname: Cáceres
authors.forename: Augusto F De La
authors.initials: AF
authors.lastname: Cruz
authors.forename: Diana
authors.initials: D
authors.lastname: Durand
authors.forename: Genevieve
authors.initials: G
authors.lastname: Housman
authors.forename: Brannon I
authors.initials: BI
authors.lastname: Hulsey
authors.forename: Gian Carlo
authors.initials: GC
authors.lastname: Iannacone
authors.forename: Paul W
authors.initials: PW
authors.lastname: López
authors.forename: Rolando
authors.initials: R
authors.lastname: Martínez
authors.forename: Ángel
authors.initials: Á
authors.lastname: Medina
authors.forename: Olimpio Ortega
authors.initials: OO
authors.lastname: Dávila
authors.forename: Karla Paloma Osorio
authors.initials: KP
authors.lastname: Pinto
authors.forename: Susan I Polo
authors.initials: SI
authors.lastname: Santillán
authors.forename: Percy Rojas
authors.initials: PR
authors.lastname: Domínguez
authors.forename: Meagan
authors.initials: M
authors.lastname: Rubel
authors.forename: Heather F
authors.initials: HF
authors.lastname: Smith
authors.forename: Silvia E
authors.initials: SE
authors.lastname: Smith
authors.forename: Verónica Rubín de Celis
authors.initials: VR
authors.lastname: Massa
authors.forename: Beatriz
authors.initials: B
authors.lastname: Lizárraga
authors.forename: Anne C
authors.initials: AC
authors.lastname: Stone
mesh_terms: D041322:Chromosomes, Human, Y; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes; D006801:Humans; D007199:Indians, South American / Q000235:genetics*; D008297:Male; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D010568:Peru; D016133:Polymerase Chain Reaction; D011157:Population Dynamics; D013020:South America
chemical_list: D004272:DNA, Mitochondrial
keywords: AMAZONIAN POPULATIONS; ANDEAN POPULATIONS; MTDNA; NATIVE AMERICANS; PEOPLING OF SOUTH AMERICA; PERU; Y-CHROMOSOME