High mitochondrial mutation rates estimated from deep-rooting Costa Rican pedigrees
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Date
2012-07Author
Castri, Loredana
Barrantes Mesén, Ramiro
Pereira Reyes, Reinaldo
Luiselli, Donata
Pettener, Davide
Barbujani, Guido
Madrigal, Lorena
Meléndez Obando, Mauricio O.
Villegas Palma, Ramón
Raventós Vorst, Henriette
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Estimates of mutation rates for the noncoding hypervariable Region I (HVR-I) of mitochondrial
DNA (mtDNA) 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 paper we analyzed 19 deep-rooting
pedigrees in a population of mixed origin in Costa Rica. We calculated two estimates of the HVRI
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 three-fold 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.
External link to the item
10.1002/ajpa.22052
artículo (arbitrado). Universidad de Costa Rica, Centro de Investigación en Biología Celular y Molecular, 2012