Fine-scale, genome-wide data can reveal patterns of genetic differentiation within and between populations that may help us discover and date historical and recent lineage divergence. Lineage divergence arises due to the evolution of reproductive isolating barriers and other barriers to gene flow, such as geographic and ecological barriers. Heather uses SNP data generated by ddRAD (double digest restriction site associated) sequencing to explore the hypothesis that geographic and ecologic barriers are restricting gene flow in one species of South American Blepharoneura fruit flies (B. sp10). She uses two statistical methods to detect population structure and find evidence of multiple genetic groupings. I then explore whether these genetic patterns are associated with geographical and/or ecological barriers. Finally, Heather uses approximate Bayesian computation to infer the evolutionary history of B. sp10, and date key evolutionary events to the late Pleistocene.