Genetic structure, cryptic species, and hybridization

Abstract The term gene flow describes the spatial movement of genes within or between populations within species or between closely related species (that are not completely reproductively isolated) and plays an important role in the evolutionary trajectories of populations by changing allele frequencies and affecting the genetic diversity of populations. This chapter reviews our contemporary understanding of population genetic structure, cryptic species, and hybridization in odonates, framing it within a conservation context. We highlight the most common markers used and suggest the direction for future studies, including broadening research regions to collect data outside Europe, as genomic resources continue to advance.