DNA barcodes highlight genetic diversity patterns in rodents from desert and Andean areas of Argentina

A. OJEDA; ALEX BORISENKO; NATALIA IVANOVA; AGUSTINA NOVILLO; CECILIA LANZONE; DANIELA RODRIGUEZ; PABLO CUELLO; FERNANDA CUEVAS; PABLO JAYAT; RICARDO A. OJEDA

Ontario

Conferencia; International Barcode of Life Conference; 2015

BackgroundMuch ofSouth America consists of diverse arid-semiarid regions characterized by highmammal endemism as a result of interplay between place and lineage histories.Rodents are important component in this scenario (with more than 2,200 speciesrepresenting this most diverse order among mammals). The high diversity andcomplex evolutionary history has motivated researchers to study the phylogenetic relationships andtaxonomy which have been under continuous revision. Despite being an importantcomponent of local faunas, rodents pose a major challenge for species-leveldiagnostics, due to complex phylogeographic history and obscure morphological features.We evaluated DNA barcodes as a tool for assessing the taxonomic and geneticdiversity in the two major lineages of rodents: the ?caviomorphs? and?sigmodontines?, from arid regions of Argentina. We analyzed 304 COI barcodesrepresenting 32 species from 56 localities along Argentinean Central Andes andlowland desert.ResultsThe NJ, MP, ML tree provided clear distance based separation between allcurrently recognized species in our dataset with >95% bootstrap support. Nocases of sequence overlap between species were observed. Phyllotis xanthopygus, showed divergences of up to 13.0% betweengeographically separated lineages and strong correspondence between genetic andgeographic structure, suggesting cryptic speciation. Akodon spegazzinii and Tympanoctomysbarrerae, contained geographically separated clusters with up to 2.3%divergence. Most species demonstrated low COI variation (P-distance 0?2.2%) andno geographic pattern. Mean nearest neighbor distances between congenericspecies varied from 3.0?12.6%, except two closely related forms within Euneomys.SignificanceTheobserved DNA barcode divergence provide insights into the complexphylogeographic patterns and speciation scenarios in desert Andean rodents andhighlight areas requiring in-depth taxonomic research, with potentialimplications in conservation and human health.