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Microevolutionary processes due to landscape features in the province of Jujuy (Argentina)

Authors

  • Luis Gómez-Pérez,

    1. Departamento de Genética y Antropología Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco, 48080 Bilbao, Spain
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  • Miguel A. Alfonso-sánchez,

    1. Departamento de Genética y Antropología Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco, 48080 Bilbao, Spain
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  • José E. Dipierri,

    1. Instituto de Biología de la Altura, Universidad Nacional de Jujuy, 4600 San Salvador de Jujuy, Argentina
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  • Emma Alfaro,

    1. Instituto de Biología de la Altura, Universidad Nacional de Jujuy, 4600 San Salvador de Jujuy, Argentina
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  • Susana García-Obregón,

    1. Departamento de Genética y Antropología Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco, 48080 Bilbao, Spain
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  • Marian M. De Pancorbo,

    1. Departamento de Zoología y Dinámica Celular Animal, Facultad de Farmacia, Universidad del País Vasco, 01006 Vitoria, Spain
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  • Graciella Bailliet,

    1. Laboratory of Human Molecular Population Genetics, IMBICE, La Plata, Argentina
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  • José A. Peña

    Corresponding author
    1. Departamento de Genética y Antropología Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco, 48080 Bilbao, Spain
    • Departamento de Genética, Antropología Física y Fisiología Animal, Universidad del País Vasco, Apartado 644, 48080 Bilbao, Spain
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Abstract

Objectives: We seek to evaluate the influence of a diverse and rugged physical environment on the genetic background of human populations.

Methods: We analyzed eight polymorphic Alu insertions in 226 individuals from Jujuy province (Argentina), which is composed of several regions with well-defined geographical features and marked contrasts between them associated with differences in altitude (range: 700-3300 m). This regional division was used to assess the spatial variation of the Alu diversity.

Results: Deviations from Hardy-Weinberg Equilibrium expectations resulting from heterozygous deficit were found for FXIIIB and PV92 in the highest subpopulations. Several Alu elements showed genetic heterogeneity between the highest region (La Puna) and the lowest regions (Valle and Selva). Similarly, a decreasing trend of the average heterozygosity according to altitude was found. Both the centroid method and the admixture analysis unveiled a gene flow above the average in lowland populations, indicating a higher proportion of foreign genes introduced by immigrants of European and African ancestry. Furthermore, several Alu frequency clines fitting the orientation of the altitude gradient were detected.

Conclusions: Our study reveals a spatial patterning of the Alu diversity in Jujuy, most likely determined by disparities in landscape and environmental features between the different subregions. Differences in the physical environment would have drastically reduced the homogenizing effects of the gene flow and would have promoted genetic drift episodes in the highest subpopulations. Microevolutionary processes detected in Jujuy have played an important role in the shaping of the gene pool of the populations from this sub-Andean zone from Argentina. Am. J. Hum. Biol., 2010. © 2010 Wiley-Liss, Inc.

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