Do xeric landscapes increase genetic divergence in aquatic ecosystems?
Thomas EP, Blinn DW, Keim P. 1998. Do xeric landscapes increase genetic divergence in aquatic ecosystems?. Freshwater Biology. 40:587-593
1. Previous investigations of the ecological genetics among amphipods in south-western U.S.A. suggested a xeric landscape promoted genetic divergence among passively dispersed freshwater invertebrates, thereby enhancing speciation events. We predicted that less divergence would occur among amphipod populations across similar geographic distances in mesic regions. 2. Eight Hyalella azteca populations were sampled along a 200-km transect in western Oregon, U.S.A. Genetic distances among populations were estimated from randomly ampli®ed polymorphic DNA (RAPD). Genetic analyses indicated much less divergence among Oregon populations than among Arizona populations in an arid environment. 3. Behavioural observations support the genetic data: Oregon populations exhibit little differentiation in swimming behaviour, whereas Hyalella populations in Arizona exhibit extremes in swimming behaviour. 4. These results provide preliminary support for the hypothesis that a xeric landscape promotes genetic and behavioural divergence among amphipods. Many aquatic invertebrates classi®ed as panmictic populations may encompass genetically distinct groups; those isolated by a xeric landscape are especially prone to diversi®cation.
- Type
- Journal Article
- Authors
- Thomas, E.; Blinn, Dean; Keim, Paul
- Units
- MOCA
- Keywords
- 3, amphipod, Animal Studies, Animals, Dispersal, Evolution, Genetics, Invertebrates, NRCA, Want, Xeric Landscapes