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

OJEDA, AGUSTINA A.; BORISENKO, ALEX; IVANOVA, NATALIA; NOVILLO, AGUSTINA; LANZONE, CECILIA; RODRÍGUEZ, MARIA DANIELA; CUELLO, PABLO; CUEVAS, MARÍA FERNANDA; JAYAT, PABLO; OJEDA, RICARDO

Guelph

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 a result of interplay between place and lineage histories. Rodents are important components in this scenario (with more than 2200 species representing this most diverse order among mammals). The high diversity and complex evolutionary history has motivated researchers to study phylogenetic relationships and taxonomy, which have been under continuous revision. Despite being an important component of local faunas, rodents pose a major challenge for species-level diagnostics, due to complex phylogeographic history and obscure morphological features. We evaluated DNA barcodes as a tool for assessing the taxonomic and genetic diversity in the two major lineages of rodents: the ?caviomorphs? and ?sigmodontines?, from arid regions of Argentina. We analyzed 310 COI barcodes representing 32 species from 56 localities along the Argentinean Central Andes and lowland desert. Results: The NJ, MP, and ML trees provided clear distance-based separation between all currently recognized species in our dataset with >95% bootstrap support. No cases of sequence overlap between species were observed. Phyllotis xanthopygus showed divergences of up to 13.0% between geographically separated lineages and strong correspondence between genetic and geographic structure, suggesting cryptic speciation. Akodon spegazzinii and Tympanoctomys barrerae 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-neighbour distances between congeneric species varied between 3.0% and 12.6%, except for two closely related forms within Euneomys. Significance: The observed DNA barcode divergence patterns provide insights into the complex phylogeographic patterns and speciation scenarios in desert Andean rodents and highlight areas requiring in-depth taxonomic research, with potential implications in conservation and human health.