Journal of Heredity Advance Access originally published online on August 28, 2007
Journal of Heredity 2007 98(6):620-628; doi:10.1093/jhered/esm068
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High Incidence of Nonslippage Mechanisms Generating Variability and Complexity in Eurasian Badger Microsatellites
From the Genètica de la Conservació, Institut de Recerca i Tecnologia Agroalimentàries, Carretera de Cabrils s/n, Cabrils (Barcelona), Spain (López-Giráldez, Marmi, and Domingo-Roura); the Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Dr Aiguader 80, 08003 Barcelona, Spain (López-Giráldez and Domingo-Roura); and the Departament de Ciència Animal i dels Aliments, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain (Marmi)
Address correspondence to Dr F. López-Giráldez at the address above, or e-mail: francesc.lopez{at}gmail.com.
The use of microsatellites in population genetics is hindered by a lack of understanding of the pattern and origin of mutations, the need to develop more specific and better computational models, and a paucity of information about specific taxa and loci. We analyzed between 4 and 10 allele sequences from 10 different microsatellites in Eurasian badgers in order to determine the compliance of the sequences with stepwise mutation models and the origin of that variability which cannot be detected through standard genotyping procedures. All microsatellite loci exhibited imperfections and/or substitutions and indels in the flanking region, as well as additions or deletions of repeat units. Our data set of sequences showed a higher number of imperfect repeats than other published badger and carnivore sequences. This could be attributed to the process of loci isolation because when genetic variability is low, researchers may be more likely to use imperfect loci if these are variable in the population being studied. Locus Mel15 had 2 repetitive arrays: one was part of a polypyrimidine region of a carnivoran short interspersed nuclear element (CAN-SINE) and the other was located in an A-rich region typical of these insertions. In spite of this complexity, heterozygosity was correlated with the maximum number of repeats. Thus, although new theoretical models are being evolved to cover complex patterns of microsatellite mutation, sequencing electromorphs is needed to identify microsatellites or portions of them whose evolution can be modeled under simple models.
Corresponding Editor: Oliver Ryder