Microsatellite analysis supports mitochondrial phylogeography of the hellbender (Cryptobranchus alleganiensis)

We investigated genetic diversity of the hellbender (Cryptobranchus alleganiensis) throughout its range in the eastern US using nuclear markers and compared our results to a previously published mitochondrial analysis. A variety of nuclear markers, including protein-coding gene introns and microsatellites were tested but only microsatellites were variable enough for population level analysis. Microsatellite loci showed moderate among population sharing of alleles, in contrast to the reciprocal monophyly exhibited by mitochondrial DNA. However, analyses using F-statistics and Bayesian clustering algorithms showed considerable population subdivision and clustered hellbender populations into the same major groups as the mtDNA. The microsatellites combined with the mtDNA data suggest that gene flow is severely restricted or non-existent among eight major groups, and potentially among populations (rivers) within groups. The combined mtDNA and microsatellite data suggest that the currently recognized hellbender subspecies are paraphyletic. We suggest that the eight independent groups identified in our study should be managed as such, rather than basing conservation decisions on the two named subspecies of hellbender.