Genetic Structure of the Frogs Geocrinia lutea and Geocrinia rosea Reflects Extreme Population Divergence and Range Changes, Not Dispersal Barriers

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Society for the Study of Evolution is collaborating with JSTOR to digitize, preserve and extend access to Evolution.Abstract.-I describe the genetic structure of two frog species, Geocrinia rosea and Geocrinia lutea, using allozyme electrophoresis to understand population structure and thereby possible mechanisms of divergence and speciation. The sampling regimes represented the entire range of both species and provided replicated tests of the impact of ridges, rivers, and dry forest on gene flow. Geocrinia rosea and G. lutea were highly genetically subdivided (FST = 0.69, 0.64, respectively). In the extreme, there were fixed allelic differences between populations that were only 4 km (G. rosea) or 1.25 km (G. lutea) apart. In addition to localized divergence, two-dimensional scaling of genetic distance allowed the recognition of broad-scale genetic groups, each consisting of several sample sites. Patterns of divergence were unrelated to the presence of ridges, rivers, or dry forest. I argue that range contraction and expansion, combined with extreme genetic divergence in single, isolated populations, best accounts for the genetic structure of these species.

Microsatellite variation and fine‐scale population structure in the wood frog (Rana sylvatica)

“…Among studies with some overlap with our range of distances, most found genetic variation to be, on average, as or more subdivided than we found for R. sylvatica (Routman 1993; Hitchings & Beebee 1997; Call et al . 1998; Driscoll 1998; Seppä & Laurila 1999; Rowe et al . 2000; Shaffer et al .…”

Outbreeding depression in the common frog, Rana temporaria

“…Amphibians show the strongest genetic differentiation between populations of all vertebrates (Ward et al 1992;Driscoll 1998). This is partly due to restricted dispersal abilities (e.g.…”

“…This is partly due to restricted dispersal abilities (e.g. Berven & Grudzien 1990;Ward et al 1992;Driscoll 1998, but see Seppa¨& Laurila 1999;Newman & Squire 2001), strong philopatry (Berven & Grudzien 1990;Reading et al 1991), and a patchy distribution of breeding localities (Ward et al 1992;Driscoll 1998;Lampert et al 2003). Furthermore, amphibian species are commonly composed of a mosaic of large and small populations, differing in degree of genetic variation and often with very restricted gene flow even between closely situated populations (Hitchings & Beebee 1997;Newman & Squire 2001;Lampert et al 2003;Brede & Beebee 2004).…”

Genetic Structure of the Blue Ridge Dusky Salamander (Desmognathus Orestes): Inferences From Allozymes, Mitochondrial Dna, and Behavior

“…Microevolutionary forces important in population divergence and speciation are often inferred from the geographic distribution of allozyme variants (Tilley and Mahoney 1996;Armbruster et al 1998;Bohonak 1998;Driscoll 1998;Gascon et al 1998;Ramirez and Haakonsen 1999). Although geographic variation in allozyme frequencies can identify distinct clusters of populations, it can be difficult to resolve phylogenetic relationships and distinguish among evolutionary forces that create patterns of divergence.…”