Abstract
The influence of fragmentation on local genetic population structure of the fluvial sculpin Cottus nozawae was studied by comparing populations in two regions: the Tohoku District (the southern margin of the species' native range) and Hokkaido Island (the center of its native range), Japan, based on restriction fragment length polymorphism analysis of mitochondrial DNA amplified by means of the polymerase chain reaction. Relatively high genetic divergences were found among populations from different regions. An analysis of molecular variance showed that ΦSTvalues among samples from the same river system in the Tohoku District were higher than among samples from Hokkaido Island. Heterogeneities in haplotype composition among tributary populations and among distinctive clusters were also found in the Tohoku District river system. Cottus nozawae in the Tohoku District are distributed patchily in headwater streams and may be thermally isolated. As a result, there appears to be little gene flow among tributary populations from different areas that exhibit divergence due to random genetic drift and have small effective population sizes.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
