Date of Award

Summer 8-2019

Degree Type


Degree Name

Master of Science - Biology



First Advisor

Dr. Matthew Kwiatkowski

Second Advisor

Dr. Jennifer Gumm

Third Advisor

Dr. Beatrice Clack

Fourth Advisor

Dr. Donald Pratt


Among major vertebrate groups, anurans are understudied with regards to their visual systems and how they function. This study sampled North American anurans representing diverse evolutionary and life histories and which likely possess visual systems adapted to meet different ecological needs. Using standard molecular techniques, sequences were obtained for four opsins—the protein component of visual pigments—expressed in anuran retinas. Amino acid sequences of the genes RH1, LWS, SWS1, and SWS2 were compared across taxa to identify variable sites, as such variation can shift the spectral sensitivity of visual pigments and thus alter dim-light and color vision. Some of the amino acid changes observed are known to tune spectral sensitivity in other vertebrates, and tests for positive selection revealed additional candidate tuning sites in LWS. The observed variation cannot fully be explained by evolutionary relationships among species. Taken together, results suggest that other factors may be driving changes to anuran visual systems.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.



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