1. American Bullfrog (Lithobates catesbeianus) Phylogeny
Lisa M. Wilson
April 26, 2010

2. Introduced Species
Introduced species are a major cause of endangerment of species in the U.S.
400 of 958 species in U.S.
Huge economic impact

3. American Bullfrog Successful colonizer
Native to North America east of the Mississippi River
Introduced to western North America, China, Venezuela, Brazil, Europe…
Preys on and outcompetes native species
Acts as reservoir and vector of chytrid

4. Invasive Management Eradication impossible Management for coexistence
Prevention!
Climate matching is best predictor
Legislation to control intentional introductions
Is there variability between populations within Bullfrog range that affect climate matching ability?

5. Project Goal
Use available sequence data to look for differences between populations that may be related to climatic variables

6. Methods Cytochrome b sequences for Bullfrog and Green Frog from NCBI
Aligned in Seaview using ClustalW
Maximum-likelihood tree created with RAxML
1000 bootstraps
Tree visualized and modified in FigTree
Compared arrangement of source populations in tree with climate variables
Locations from original papers (Austin et al. 2003, 2004)

7. Results

8. Drought Tolerance Closely related and relatively recent
Founder effects
Requires same genetic drift between all populations
China, Java, California, Texas, Missouri, Kansas?
From most arid locations
Cyt b could be related to drought tolerance
Role in cellular respiration

9. Discussion No influence of temperature
Thermal tolerances not heritable
Cyt b not related to thermal tolerances
Distribution of cyt b haplotypes determined by refugia during last glacial maximum
New York is basal, Ontario closely related to Florida
High rate of gene flow – human mediated transport?

10. Summary Limited by data availability
Cytochrome b only widely available sequence
Limited known locations
More populations, more genes, ideally related genes!