Population subdivision in marine environments: the contributions of biogeography, geographical distance and discontinuous habitat to genetic differentiation in a blennioid fish, Axoclinus nigricaudus

• DOI: 10.1046/j.1365-294x.2001.01294.x
• Publication Date: 2003-03-12T10:42:52Z
• Authors: C. Riginos; M. W. Nachman
• Keywords: Isolation by distance; Geographical distance; Mantel test; Genetic distance; Population Genetics

The relative importance of factors that may promote genetic differentiation in marine organisms is largely unknown. Here, contributions to population structure from a biogeographic boundary, geographical distance and the distribution suitable habitat were investigated Axoclinus nigricaudus, small subtidal rock-reef fish, throughout its range Gulf California. A 408-bp fragment mitochondrial control region was sequenced 105 individuals. Variation significantly partitioned between 28 36 possible combinations pairs. Phylogenetic analyses, hierarchical analyses variance modified Mantel test substantiated major break two putative regions. This discontinuity coincides with an abrupt change ecological characteristics, including temperature salinity, but does not coincide known oceanographic circulation patterns or any historic barriers. There overall relationship increasing pairs, manner consistent isolation-by-distance. significant habitat-by-geographical-distance interaction term indicated that, for given distance, populations separated by discontinuous (sand) are more distinct genetically than continuous (rock). In addition, deep open waters These results indicate levels among A. nigricaudus cannot be explained single factor, due combined influences biogeography, availability habitat.