High mitochondrial mutation rates estimated from deep-rooting costa rican pedigrees

Authors

  • Lorena Madrigal,

    1. Department of Anthropology, University of South Florida, Tampa, FL 3360
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  • Loredana Castrì (Posthumously),

    1. Dipartimento di Biologia evoluzionistica sperimentale. Area di Antropologia, Università di Bologna, Via Selmi 3, 40126 Bologna, Italy
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  • Mauricio Melendez-Obando,

    1. Academia Costarricense de Ciencias Genealógicas, 1771-1002, Paseo de los Estudiantes, San José, Costa Rica
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  • Ramon Villegas-Palma,

    1. Academia Costarricense de Ciencias Genealógicas, 1771-1002, Paseo de los Estudiantes, San José, Costa Rica
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  • Ramiro Barrantes,

    1. Escuela de Biología, Universidad de Costa Rica, Ciudad Universitaria Rodrigo Facio, San Pedro de Montes de Oca, 2050, Costa Rica Universidad de Costa Rica
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  • Henrieta Raventos,

    1. Escuela de Biología, Universidad de Costa Rica, Ciudad Universitaria Rodrigo Facio, San Pedro de Montes de Oca, 2050, Costa Rica Universidad de Costa Rica
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  • Reynaldo Pereira,

    1. Escuela de Biología, Universidad de Costa Rica, Ciudad Universitaria Rodrigo Facio, San Pedro de Montes de Oca, 2050, Costa Rica Universidad de Costa Rica
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  • Donata Luiselli,

    1. Dipartimento di Biologia evoluzionistica sperimentale. Area di Antropologia, Università di Bologna, Via Selmi 3, 40126 Bologna, Italy
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  • Davide Pettener,

    1. Dipartimento di Biologia evoluzionistica sperimentale. Area di Antropologia, Università di Bologna, Via Selmi 3, 40126 Bologna, Italy
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  • Guido Barbujani

    Corresponding author
    1. Dipartimento di Biologia ed Evoluzione, Università di Ferrara, Via L. Borsari 46, 44121 Ferrara, Italy
    • Department of Biology and Evolution, University of Ferrara, Via L. Borsari 46, 44121 Ferrara, Italy
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Abstract

Estimates of mutation rates for the noncoding hypervariable Region I (HVR-I) of mitochondrial DNA vary widely, depending on whether they are inferred from phylogenies (assuming that molecular evolution is clock-like) or directly from pedigrees. All pedigree-based studies so far were conducted on populations of European origin. In this article, we analyzed 19 deep-rooting pedigrees in a population of mixed origin in Costa Rica. We calculated two estimates of the HVR-I mutation rate, one considering all apparent mutations, and one disregarding changes at sites known to be mutational hot spots and eliminating genealogy branches which might be suspected to include errors, or unrecognized adoptions along the female lines. At the end of this procedure, we still observed a mutation rate equal to 1.24 × 10−6, per site per year, i.e., at least threefold as high as estimates derived from phylogenies. Our results confirm that mutation rates observed in pedigrees are much higher than estimated assuming a neutral model of long-term HVRI evolution. We argue that until the cause of these discrepancies will be fully understood, both lower estimates (i.e., those derived from phylogenetic comparisons) and higher, direct estimates such as those obtained in this study, should be considered when modeling evolutionary and demographic processes. Am J Phys Anthropol 148:327–333, 2012. © 2012 Wiley Periodicals, Inc.

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