Class
Article
College
Emma Eccles Jones College of Education and Human Services
Department
English Department
Faculty Mentor
Shana L. Geffeney
Presentation Type
Poster Presentation
Abstract
A central goal of evolutionary genetics is to understand how contingency and constraint shape evolutionary trajectories of protein evolution. There is considerable evidence that the fitness consequences of mutations are dependent on the genetic background in which they occur. This context dependence means that understanding the effects of putatively adaptive mutations as well as the evolutionary history of novel protein function can be difficult. An ideal approach might be a “protein time machine” in which mutations of interest are inserted into ancient ancestral gene sequences and their effects quantified. When multiple mutations are thought to be important, the order of these mutations can be tested to replicate the actual evolutionary history of the protein in question. Here we report our construction of a “protein time machine” to study the evolution of adaptive TTX resistance in garter snake predators. These snakes have evolved extreme resistance to TTX because of coevolution with TTX-bearing salamanders. Our work uses ancestral sequence reconstruction to predict the sequence of a voltage-gated sodium channel (the target of TTX) that was present in the ancestor of modern resistant snakes (rough 50,000 YA). We used protein modelling to estimate the TTX binding energy of this VGSC and to test whether the channel forms hydrogen bonds with TTX. Finally, we constructed a synthetic expression vector that includes the coding sequence of this VGSC coupled with regulatory and promotor sequences that will be used to express this protein in a Xenopus oocyte expression system to replicate the last 50,000 years of evolution in this protein.
Location
Logan, UT
Start Date
4-7-2022 12:00 AM
Included in
Protein Time Machine: Creating an Ancestral Voltage Gated Sodium Channel of Thamnophis sirtalis
Logan, UT
A central goal of evolutionary genetics is to understand how contingency and constraint shape evolutionary trajectories of protein evolution. There is considerable evidence that the fitness consequences of mutations are dependent on the genetic background in which they occur. This context dependence means that understanding the effects of putatively adaptive mutations as well as the evolutionary history of novel protein function can be difficult. An ideal approach might be a “protein time machine” in which mutations of interest are inserted into ancient ancestral gene sequences and their effects quantified. When multiple mutations are thought to be important, the order of these mutations can be tested to replicate the actual evolutionary history of the protein in question. Here we report our construction of a “protein time machine” to study the evolution of adaptive TTX resistance in garter snake predators. These snakes have evolved extreme resistance to TTX because of coevolution with TTX-bearing salamanders. Our work uses ancestral sequence reconstruction to predict the sequence of a voltage-gated sodium channel (the target of TTX) that was present in the ancestor of modern resistant snakes (rough 50,000 YA). We used protein modelling to estimate the TTX binding energy of this VGSC and to test whether the channel forms hydrogen bonds with TTX. Finally, we constructed a synthetic expression vector that includes the coding sequence of this VGSC coupled with regulatory and promotor sequences that will be used to express this protein in a Xenopus oocyte expression system to replicate the last 50,000 years of evolution in this protein.