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Abstract:
Populations at the edge of their range often
invoke taxonomic confusion and are increasingly considered
to harbour cryptic genetic diversity of significant
adaptive potential. In the Peace River region of northwestern
Canada, three sculpin species have been reported:
spoonhead (Cottus ricei), slimy (Cottus cognatus) and
prickly (Cottus asper) sculpin. Prickly sculpin occurrence
in this region represents the most eastern edge of its distribution,
but its status has remained uncertain following its
initial discovery in 1989. These populations may represent
an independently evolving lineage of special conservation
concern, or be the consequence of an ongoing range
expansion, possibly accompanied by interspecific hybridization
with local species. Using a combination of mtDNA
sequencing and microsatellite analyses, we did not find
peripheral population differentiation or interspecific
hybridization, suggesting that the Albertan Peace River
population belongs to the same genetic group as its western
counterparts. Future studies will benefit from a greater
understanding of whether demographically independent
prickly sculpin populations established in Alberta without
the typical genetic signatures of expansion at the periphery
of their range.