Layla Freeborn on the genetic and morphological basis of color variation in a highly polymorphic poison frog

University of Pittsburgh Department of Biological Sciences Presents

E&E Wednesday Noon Seminars 2017-2018

Layla Freeborn - University of Pittsburgh

The genetic and morphological basis of color variation in a highly polymorphic poison frog.

The strawberry poison dart frog, Oophaga pumilio, is characterized by striking color variation within and across islands of the Bocas del Toro archipelago of Panama. Despite a number of studies that aim to understand the selective pressures that generated or maintain this variation, relatively little is known about its underlying genetic and morphological basis. To this end, my research attempts to bridge this gap by (1) leveraging the power of next-generation sequencing to find loci associated with color differences, (2) describing how the composition of pigment cells and their constituent pigments vary among morphs, and (3) using phylogenetics and character state mapping to elucidate the evolution of these morphological traits. Here I present the results of the association study and linkage mapping analysis, in which I have identified 18 loci that are associated with differences among morphs from two polymorphic populations. I have employed several strategies to attempt an integration of these candidate color loci with a novel linkage map for O. pumilio. Results of one strategy, the pseudo testcross, suggests that the loci associated with coloration lie in multiple regions of the genome, although the absence of many bridge loci prevent a sex-averaged map. Despite difficulty in determining the genetic basis of coloration, morphological analyses of pigment cells in combination with a population-level phylogeny will provide an opportunity to better understand the mechanism and evolution of this extraordinary example of phenotypic variation.

Wednesday, April 25, 2018

A219B Langley Hall

12:00 PM Seminar


25 Apr 2018

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A219B Langley Hall