Catchment population structure and divergence patterns of the rainbow darter Etheostoma caeruleum (Percidae: Teleostei), an eastern North American benthic fish, are tested using a landscape genetics approach. Allelic variation at eight...
moreCatchment population structure and divergence patterns of the rainbow darter Etheostoma caeruleum
(Percidae: Teleostei), an eastern North American benthic fish, are tested using a landscape genetics
approach. Allelic variation at eight nuclear DNA microsatellite loci and two mitochondrial DNA
regions [cytochrome (cyt) b gene and control region; 2056 aligned base pairs (bp)] is analysed
from 89 individuals and six sites in the Lake Erie catchment (Blanchard, Chagrin, Cuyahoga and
Grand Rivers) v. the Ohio River catchment (Big Darby Creek and Little Miami River). Genetic
and geographic patterning is assessed using phylogenetic trees, pair-wise FST analogues, AMOVA
partitioning, Mantel regression, Bayesian assignment, 3D factorial correspondence and barrier analyses.
Results identify 34 cyt b haplotypes, 22 control region haplotypes and 137 microsatellite
alleles whose distributions demonstrate marked genetic divergence between populations from the
Lake Erie and Ohio River catchments. Etheostoma caeruleum populations in the Lake Erie and
Ohio River catchments diverged c. 1·6 mya during the Pleistocene glaciations. Greater genetic separations
characterize the Ohio River populations, reflecting their older habitat age and less recent
connectivity. Divergence levels within the Lake Erie catchment denote more recent post-glacial
origins. Notably, the western Lake Erie Blanchard River population markedly differs from the three
central basin tributary samples, which are each genetically distinguishable using microsatellites.
Overall relationships among the Lake Erie sites refute a genetic isolation by geographic distance
hypothesis. Etheostoma caeruleum populations
