Genomic data support reticulate evolution in whiptail lizards from the Brazilian Caatinga
Year: 2024
Type: article
Abstract: • We found mitonuclear incongruences in the Ameivula ocellifera group using ultraconserved elements and mitogenomes. • Coalescent simulations suggest introgressive mitochondrial capture as the main cause of mitonuclear incongruences. • Individuals with mitonuclear incongruences were supported as a distinct species by species delimitation methods. • Mitogenome evolution could be neutral, with autosomal selection against hybridization or mediated by mitonuclear incompatibilities. Species relationships have traditionally been represented by phylogenetic trees, but not all evolutionary histories fit into bifurcating divergence models. Introgressive hybridization challenges this assumption by sometimes [or maybe often] leading to mitochondrial introgression, wherein one species’ mitochondrial genome is entirely replaced by another’s (mitochondrial capture). Such processes result in mitonuclear discrepancies, complicating species delimitation and phylogenetic inference. In our study, we used ultraconserved elements (UCE) and mitogenomic data to investigate the evolutionary history of the Ameivula ocellifera complex, a group of South American whiptail lizards widely distributed in semiarid environments of the Caatinga Domain in Brazil. We examine mitonuclear discordances, assessing reticulate evolution, evaluating species limits, and testing for adaptive mitochondrial capture that could explain higher introgression in the mitochondrial genome compared to nuclear DNA. Our findings support the occurrence of an ancient reticulation event during the diversification of these lizards, driven by introgressive hybridization, leading to mitochondrial capture, and explaining mitonuclear discrepancies. Overall, we did not find clear evidence of positive selection across mitochondrial protein-coding genes suggesting adaptive mitochondrial capture of individuals with introgressed mtDNA. Thus, the genetic diversification and mitogenome evolution could be neutral, with selection against hybridization in the autosomal loci only, or even mediated by mitonuclear incompatibilities. Analyses of mtDNA genomes alongside network and species delimitation methods were crucial for identifying and validating individuals with introgressed mtDNA as a distinct species, demonstrating the potential of genome sampling, and using innovative analytical techniques for elucidating speciation processes in the presence of introgressive hybridization.
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,640
OpenAlex ID: W4405752324