Multiplexed microsatellite loci in American crow (Corvus brachyrhynchos): a severely affected natural host of West Nile virus.

Recent advances in high throughput molecular techniques have allowed the development of cost- and time-effective libraries of molecular markers, such as microsatellites, for population genetic studies in non-model species. The American crow, Corvus brachyrhynchos, is recognized to be one of the species that has been most negatively affected by the emergence of West Nile virus (WNV) in North America in 1999. Genetic monitoring of the process of a declining population after the introduction of an infectious disease can provide insights into the demographic and evolutionary impact of a pathogen in a natural host population over time. In this study, shotgun pyrosequencing and validation of previously published cross-species markers were the approaches used to identify and develop a set of 32 polymorphic loci for the C. brachyrhynchos. Since the American crow is morphologically similar to the sympatric species Fish crow (Corvus ossifragus), we also designed a real-time PCR protocol to rapidly differentiate these two species using a set of primers and probes that can discriminate a section of the COI gene at the mitochondrial DNA. These new markers together with a faster method for species verification will allow further detailed studies to characterize and compare genetic diversity of historic and contemporary C. brachyrhynchos populations.