Meeting Abstract
The world has seen an unprecedented increase in anthropogenic inputs of numerous elements since the onset of the industrial revolution, often leading to perturbed or destroyed ecosystems. Heavy metals sourced from the byproducts of mining activities are common contaminants in the biosphere and can have detrimental effects at all levels of biological organization. The Tri-State Mining District of Kansas, Missouri, and Oklahoma has long been characterized by elevated heavy metal concentrations in animals and humans from improper waste management, leading to the designation of the Tar Creek Superfund Site. The surviving ichthyofaunal community of Tar Creek is dominated by Western mosquitofish (Gambusia affinis), which also inhabit neighboring, unpolluted watersheds, facilitating comparative analyses of physiological and evolutionary responses to heavy metal pollution. We coupled molecular evolutionary analyses in related fishes inhabiting extreme environments with RNA-sequencing of gill, liver, and brain tissues of G. affinis to address basic questions regarding evolutionary responses to heavy metal stress: 1) which genes are experiencing positive selection in populations of G. affinis inhabiting polluted habitats?, and 2) what genes are differentially expressed between populations of G. affinis? We hypothesized that genes involved with metal homeostasis would be under positive selection and be upregulated in the Tar Creek population of G. affinis. These analyses will allow us to investigate how heavy metal pollution might impact rapid evolutionary responses and understand the mechanisms that have allowed G. affinis to inhabit heavy metal contaminated extreme environments.
