Phylogeographic Contributions to Genetic Biodiversity in the Great Lakes Basin

Our understanding of historical events and recolonization history of freshwater fishes in Canada has grown substantially over the past several decades, and has benefited enormously from advances in genetic tools and techniques.  Genetic tools have provided tremendous insights into the identity, history and relationships of species and populations, allowing us to see into their evolutionary and ecological past.  Phylogeographic analyses have enabled the resolution of relationships among intraspecific populations dating back across millenia, and have provided valuable insights regarding the number and location of glacial refugia used by different species, as well as the timing and duration of recolonization events.  In many cases, species colonized the Great Lakes basin from multiple refugia, with intraspecific secondary contact contributing to the genetic diversity and adaptive resources of postglacial populations.  Phylogenetic reconstruction of species complexes and intraspecific ecotypes indicates that several species groups arose in situ following glacial retreat, potentially as a result of ecological opportunity.  Many freshwater species in Canada bear strong genetic signatures of Pleistocene glacial and interglacial events, with differences in species ecology and their interaction with postglacial environments resulting in qualitatively different patterns among species.  In several cases, coalescent analyses of genetic data have enabled inference of historical demographics across ecological and evolutionary timescales.  This wealth of genetic information has helped inform and augment previous data sources such as morphometric analyses, physiology, parasitology, and geological records, and has helped provide a richer understanding of historical events and processes in the history of species and populations across dynamic postglacial landscapes.