Meeting Abstract
We are investigating the impact of nucleotide divergence on oxidative phosphorylation (OxPhos) metabolism among populations of Fundulus heteroclitus. The OxPhos pathway occurs in mitochondria and uses oxygen to produce the majority of ATP in a cell. This pathway consists of 5 large enzyme complexes with 45 to 4 proteins per complex and is the only pathway in which the proteins involved are coded by both mitochondrial and nuclear genomes. F. heteroclitus populations have sequence divergence in OxPhos genes in both mitochondrial and nuclear genomes. These populations are distributed along a steep thermal cline on the east coast of the United States and have evolved by natural selection to adapt to this clinal variation in temperature; thus, F. heteroclitus serve as a model species to enhance our understanding of the impact of nucleotide divergence on physiological function. Two distinct mitochondrial haplotypes exist along this thermal cline, a northern and southern haplotype with a break at the Hudson River. In northern New Jersey, there is an admixture of mitochondrial haplotypes with a frequency of about 60% southern haplotype and 40% northern. We have performed a genotyping by sequencing experiment in order to determine if there is an association between the mitochondrial and nuclear genomes. OxPhos measurements were performed on 180 individuals from the admixture population and these same individuals were also genotyped. We identified 16,489 single nucleotide polymorphisms (SNP), called in 70% of individuals. There are about 500 SNPs with significant FST values (p < 0.01) when haplotypes are used as a grouping factor. This is suggestive of an epistatic interaction between the mitochondrial and nuclear genome.
