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?semiaridregions characterized by high mammal endemism as a result ofinterplay between place and lineage histories. Rodents are importantcomponents in this scenario (with more than 2200 species representingthis most diverse order among mammals). The high diversity andcomplex evolutionary history has motivated researchers to study phylogeneticrelationships and taxonomy, which have been under continuousrevision. Despite being an important component of local faunas,rodents pose a major challenge for species-level diagnostics, due tocomplex phylogeographic history and obscure morphological features.We evaluated DNA barcodes as a tool for assessing the taxonomicand 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 localitiesalong the Argentinean Central Andes and lowland desert.Results: The NJ, MP, and ML trees provided clear distance-basedseparation between all currently recognized species in our datasetwith >95% bootstrap support. No cases of sequence overlap betweenspecies were observed. Phyllotis xanthopygus showed divergences of upto 13.0% between geographically separated lineages and strong correspondencebetween genetic and geographic structure, suggestingcryptic speciation. Akodon spegazzinii and Tympanoctomys barrerae containedgeographically 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 distancesbetween congeneric species varied between 3.0% and 12.6%, except fortwo closely related forms within Euneomys. Significance: The observedDNA barcode divergence patterns provide insights into thecomplex phylogeographic patterns and speciation scenarios in desertAndean rodents and highlight areas requiring in-depth taxonomicresearch, with potential implications in conservation and humanhealth.