Introgression as a likely cause of mtDNA paraphyly in two allopatric skippers (Lepidoptera: Hesperiidae)

Abstract

Gene transfer between species during interspecific hybridization is a widely accepted reality in plants but is considered a relatively rare phenomenon among animals. Here we describe a unique case of mitochondrial DNA (mtDNA) paraphyly in the skipper genus, Erynnis, that involves well-diverged allopatric species. Using molecular evidence from both mitochondrial and nuclear genomes, we found high levels of intraspecific divergence in the mitochondrial genome within E. propertius (over 4% pair-wise sequence divergence) but no such differentiation in the nuclear genome. Sequence comparisons with related Erynnis suggest that past, but recent and infrequent introgression between E. propertius and E. horatius is the most reasonable explanation for the observed pattern of mtDNA paraphyly. This example of putative introgression highlights the complexity of mtDNA evolution and suggests that similar processes could be operating in other taxa that have not been extensively sampled. Our observations reinforce the importance of involving multiple genes with different modes of inheritance in the analysis of population history of congeneric taxa.

Paternal transmission of mitochondrial DNA as an integral part of mitochondrial inheritance in metapopulations of Drosophila simulans

“…Such processes would not only impact on the evolution of the molecule but also may impact species or population fitness and may counterbalance the female selective sieve acting on mtDNA (Bromham et al, 2003;Gemmell et al, 2004;Innocenti et al, 2011). Our study shows that a replacement of maternal by paternal mtDNA is possible in single individuals but additional studies are necessary to examine whether these novel mitonuclear lineages have the capacity to propagate within entire populations in this species as reported for other species Zakharov et al, 2009). Similarly, further research is needed to evaluate the potential impact of impending heterologous recombination on dynamics of mitochondrial evolution and organismal or population fitness (Bromham et al, 2003).…”

“…In some cases, only single individuals are affected whereas in others the introgression and replacement of mtDNA haplotypes affects entire populations or species (Goodman et al, 1999;Alves et al, 2008;Oliveira et al, 2008;Zakharov et al, 2009).…”

Complete DNA barcode reference library for a country's butterfly fauna reveals high performance for temperate Europe

“…Moreover, detailed analysis of such cases can provide a better understanding of the evolutionary history of the species involved. Cases of mtDNA paraphyly caused by introgression have been previously reported in Lepidoptera [51], but they can also reflect incomplete lineage sorting in recent speciation events (all cases encountered by us involve recently diverged species pairs). We emphasize that cases of paraphyly and polyphyly do not prevent the identification of species unless they share haplotypes.…”

Nuclear genomes distinguish cryptic species suggested by their DNA barcodes and ecology

“…Whereas DNA barcoding is cheap and fast for large numbers of specimens, a deep dive into the nuclear genome, although slow and expensive, was worthwhile in this exemplary case to exclude the possibility of irregularities with barcodes (16). Therefore, we obtained genomic sequence reads for three specimens of each species from the U. kikkawai complex and single specimens of U. orcinus and U. eurus as outgroups (Fig.…”