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Lydia Bright
Postdoctoral Research Associate

Postdoctoral fellow, NIH Ruth L. Kirschstein National Research Service Award
Ph.D. 2011 Molecular Genetics and Cell Biology, University of Chicago
B.A. 1999 Biology and Studio Art, Oberlin College

My goal is to understand how fine-scale mechanisms of evolution shape membrane trafficking pathways in eukaryotic cells. Specifically, I am tracking the subcellular fates of duplicate genes, or paralogs, retained from recent whole genome duplications in species of the Paramecium aurelia complex. To do this comprehensively, I am combining evolutionary and cell biological approaches.

I am currently using members of families of membrane trafficking determinants. These proteins, which include Rab GTPases, SNAREs, and adaptor proteins, are important in both the specificity and evolution of different steps of trafficking between compartments in the cell. Importantly for my purposes, the localization of these proteins is strongly linked to function, and changes in localization are a good readout for changes in function between paralogs. By exploring exactly how members of these gene families have changed in sequence, localization and function in closely related species of Paramecium, I hope to learn more about the evolution of trafficking pathways at a detailed level.

Paralogs phylogeny

The Paramecium aurelia complex is a promising system in which to follow patterns of gene duplication, preservation and loss. The Lynch lab is currently sequencing the genomes of all members of the aurelia complex; this newly available genomic information presents an exciting opportunity to begin genetic and cell biological work within and among all of these species.
A few of the questions I'm addressing, and the tools I am using to answer them:
1) What is the balance of conservation and innovation between Rab11 paralogs across the aurelia species complex? Expression and imaging of fluorescent protein fusions.
2) What specific protein domains cause changes to closely related paralog localization patterns? Domain swapping or site-directed mutagenesis.
3) What effector (or other) interactions are causing these changes? Comparative immunoprecipitation.

My thesis work included a comprehensive look at the Rab GTPase family in another ciliate, Tetrahymena thermophila:
Bright, L, Kambesis N., Nelson SB, Jeong B, and AP Turkewitz.  (2010).  Comprehensive Analysis Reveals Dynamic and Evolutionary Plasticity of Rab GTPases and Membrane Traffic in Tetrahymena thermophila. PLoS Genetics, 14 Oct 2010.