Phylogenetic data show Antarctica’s terrestrial arthropods persisted throughout the repeated glaciation events of the Pleistocene. As ancient glacial-interglacial cycles are similar to current and future environmental changes, these species are ideal models for understanding the evolutionary responses to climate change. An area experiencing dramatic climate change is the Western Antarctic Peninsula (WAP), which is home to the Antarctic midge (Belgica antarctica). This species has developed several physiological adaptations which allow it to live and thrive in WAP’s extreme environment. For this reason, this species is an ideal model to study how ancient glacial-interglacial cycles have shaped genetic diversity, persistence and adaptation potential to climate change. Preliminary study showed that two evolutionary signals co-exist in the genetic makeup of Antarctic midge populations: 1) a signal of deep phylogeographic divergence among islands populations, which might reflect ancestral vicariance from ancient glacial-interglacial cycles, and 2) signals of recent and frequent dispersion of individuals to nearby islands. This apparent paradox might indicate the role of local selection against migrants thereby maintaining locally adapted genotypes. Population genomics offers the framework to quantify the relative role of local adaptation and neutral processes in determining the species genetic diversity. We will demonstrate how methods for demography inference (neutral processes as admixture, population size changes, etc) can help us identify the last glacial-interglacial events that left recognizable signals in the species genome. Furthermore we will show how whole-genome sequencing data can identify selective sweeps and local adaptation in the current genetic variation of the populations.
