Meeting Abstract
Although evidence for the importance of mitochondria in the evolution of natural populations continues to accumulate, studies attempting to link natural variation in mitochondrial function to mitochondrial DNA (mtDNA) variation and/or environmental variation have had mixed reports. Variation in mtDNA contributing to variation in metabolic rates can, in turn, be expected to drive differences in how organisms process energy from their environment. Previously we documented two distinct ecotypes of western terrestrial garter snakes (Thamnophis elegans) with differences in mitochondrial function, reaction norms of metabolic rate to temperature, and mtDNA sequence data. While mtDNA contributes significantly to processes within mitochondria, most gene products involved in mitochondrial function originate within nuclear DNA (nDNA). The electron transport chain (ETC), the centre for ATP production, is composed of 13 mtDNA-coded proteins and 73 nDNA-coded proteins. Here we use an expanded sequence-capture genomic sequence dataset from 96 individuals of the same and additional populations to validate previous findings that the ecotypes have unique mtDNA haplotypes with two amino acid changes in ND5 and CYTB that are highly segregated between ecotypes. This striking population structure at the mtDNA is in contrast to the low genetic structure seen in the background nDNA. We now incorporate analyses from the nDNA-coded ETC genes, comparing several bioinformatics approaches for sequence assembly and extraction of SNP data. Contrasts between the variation in mtDNA-coded and nDNA-coded ETC genes are made at the level of the gene, protein, and ETC complex and interpreted in the context of mitochondrial physiology and function.
