Genome-wide patterns of differentiation and gene flow in the Oligoryzomys flavescens (Waterhouse, 1837) complex (Rodentia, Cricetidae): preliminary evidence from RAD-seq data
Year: 2026
Type: article
Abstract: Genomic analyses, combined with environmental data, can help elucidate evolutionary processes in closely related species. Here, we used a population genomics approach to assess whether speciation processes occurred with or without genetic exchange among 3 species of the Oligoryzomys flavescens complex. Using RAD-seq, we analyzed genetic diversity, signals of positive selection, genotype–environment associations, and population structure in Oligoryzomys flavescens sensu stricto (s.s.), Oligoryzomys fornesi, and Oligoryzomys flavescens occidentalis (O. f. occidentalis). We first estimated diversity metrics and population structure with 2,008 genome-wide Single Nucleotide Polymorphisms (SNPs). Then, using Bayesian analyses, we identified 10 loci under putative positive selection and repeated the analyses only with this subset. Both datasets consistently showed that O. f. occidentalis had the highest nucleotide diversity and the greatest number of private alleles. This taxonomic entity was clearly distinct from the other 2 in all results, including principal component analysis, phylogenetic trees, and Admixture analyses. In contrast, O. flavescens s.s. and O. fornesi exhibited lower differentiation levels. Redundancy analysis indicated that elevation and seasonal temperature were the main environmental variables explaining the observed genetic structure. Furthermore, we identified possible hybridization events in contact zones between O. flavescens s.s. and O. fornesi in Chaco and Corrientes provinces and between O. f. occidentalis and O. flavescens s.s. in Córdoba province, Argentina. Our results suggest that speciation and diversification of these Neotropical rodents were shaped by interspecific gene flow in contact zones and divergent environmental pressures throughout the rest of their distribution ranges.
Source: Current Zoology
DOI: 10.1093/cz/zoag020
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W7140227510