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

AGUSTINA A. OJEDA; ALEX V. BORISENKO; N. IVANOVA; AGUSTINA NOVILLO; C LANZONE; D RODRÍGUEZ; CUEVAS, M. F.; CUELLO, PABLO; JAYAT PABLO; OJEDA RICARDO A

Guelph, Ontario, Canadá

Conferencia; 6th International Barcode of Life Conference; 2015

Background:Much of South America consists of diverse arid?semiarid regions characterized by high mammal endemism as aresult of interplay between place and lineage histories. Rodents are important componentsin this scenario (with more than 2200 species representing this most diverseorder among mammals). The high diversity and complex evolutionary history hasmotivated researchers to study phylogenetic relationships and taxonomy, whichhave been under continuous revision. Despite being an important component oflocal faunas, rodents pose a major challenge for species-level diagnostics, dueto complex phylogeographic history and obscure morphological features. Weevaluated 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 310 COI barcodes representing 32species from 56 localities along the Argentinean Central Andes and lowlanddesert. Results: The NJ, MP, and ML trees provided clear distance-based separationbetween all currently recognized species in our dataset with >95% bootstrapsupport. No cases of sequence overlap between species were observed. Phyllotisxanthopygus showed divergences of up to 13.0% between geographicallyseparated lineages and strong correspondence between genetic and geographicstructure, suggesting cryptic speciation. Akodon spegazzinii and Tympanoctomysbarrerae contained geographically separated clusters with up to 2.3%divergence. Most species demonstrated low COI variation (mean P-distance 0%?2.2%) and no geographic pattern. Mean nearest-neighbourdistances between congeneric species varied between 3.0% and 12.6%, except for twoclosely related forms within Euneomys. Significance: The observedDNA barcode divergence patterns 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.