Gene flow in the foothill yellow-legged frogs (Rana boylii) of the Eel river watershed in Mendocino National Forest.

Above: Foothill yellow legged frog (Rana boylii) from Mendocino National Forest. Former graduate student Joseph Poch (right) taking field notes.

Project Summary - My former graduate student (Joe Poch, above photo), and undergraduate (Karl Takabayashi) and I have been working to determine the amount of gene flow and genetic structuring of foothill yellow-legged frog, a threatened species of Northern California and Oregon. This is of considerable interest, because due to habitat destruction and the introduction of exotic species, amphibian species diversity is decreasing at an alarming rate. To reach the conservation goal of preserving amphibian species, fundamental questions need to be addressed such as: what is the level of gene flow in existing populations, how are individuals dispersing throughout the watershed and are there specific breeding sites which need to be preserved? Wildlife managers who have addressed these questions will be able to make better-informed decisions about how to manage habitat.

In a recent study, a genetic analysis of foothill yellow-legged frogs was conducted by examining molecular variation between individuals throughout the Eel River watershed in the Mendocino National Forest of Northern California. Two molecular markers were used: Random Amplified Polymorphic DNA and mitochondrial DNA. Three random primers from the Amersham Ready to Go RAPD Kit were used to generate RAPD profiles and the mitochondrial DNA ND2 region was sequenced from several frogs. We have compared the two datasets (RAPD & MtDNA). With the information gained from these analyses, the level of genetic diversity between subpopulations was estimated; and some genetic structuring was occurring between tributaries in the northern section and those in the southern section. Resutls suggest that distances > 10 km reduce gene flow, and perhaps sex bias dispersal is occurring in this species. For more detail, see the recently submitted manuscript below. Recent RAPD data set for the upper section of the collection site.

Relevent Publications/Presentations/Proposals:

Dever, J. A. (2007) Fine-scale genetic structure in the threatened Foothill Yellow-legged Frog (Rana boylii). Journal of Herpetology, 41(1):168-173.

Joseph Poch (graduate studetn) presented a poster at the Evolution Meeting at the University of Alaska & here is Joe's Thesis Abstract,

(Below: Left - Eel River in Mendocino National Forest, Right -typical creek where these frogs live)

Rana boylii is highly variable in its coloration These frogs were all collected in tributaries along a 20km stretch of the Eel River.

Additional field photos (extra pics of R. boylii & their habitat from recent field trips).


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