Meeting Abstract
Divergent selection pressures in heterogeneous landscapes can result in adaptive evolution to local environmental conditions. However, gene flow among populations experiencing different selection regimes can influence the propensity for local adaptation. Understanding such interactions between selection and gene flow can be achieved in systems that have more recently invaded novel/extreme environments. The Speckled Teal inhabits both low and high elevational habitat in the Andean mountain range, and while populations are thought to be largely allopatric, they are known to disperse long-distances, likely resulting in gene flow events up the altitudinal gradient. Although high-altitude Speckled Teal are believed to be locally adapted, it is unknown the extent to which gene-flow between the populations has maintained a heterogeneous genome. Therefore, we tested whether high and low elevation populations of this species are under divergent selection, as well as estimated gene flow across the genome (neutral SNPs vs. SNPs under selection), using 47,731 SNPs. In general, we find that adaptations to high-altitude environment are resulting in genomic divergence, despite high gene flow. We identified 356 SNPs as outliers under positive selection with allele frequencies strongly correlated with altitude. Among the markers under positive selection, we identified those involved in the insulin-like signaling pathway, bone morphogenesis, and blood coagulation; while markers under balancing selection were identified to be involved in metabolic processes. Ultimately, we provide the most comprehensive genomic study of this special Andean species, illustrating another example of how populations are able to adapt and invade novel, and sometimes, extreme habitats.
