Using genetic methods to investigate hybridization, residency, and epigenetics in the king-clapper rail complex
King rails (Rallus elegans) and clapper rails (R. longirostris) are two marsh bird species with similar distributions, morphology, and behavior. They are found along a salinity gradient with the king rail in freshwater marshes and the clapper in estuarine marshes. However, this separation is not absolute and there are reports of introgression. In Virginia, clapper rails are more abundant than king rails, the latter of which are listed as a species of very high conservation need. We used single nucleotide polymorphisms (SNPs), microsatellites, and patterns of DNA methylation to investigate hybridization, seasonal movements, and differential gene expression of two predominately clapper rail populations along a salinity gradient in coastal Virginia.
Application of species-specific SNPs developed across the continent showed promise for identification of rails in Virginia. SNP data suggested less hybridization among species in Virginia as compared to Louisiana, and microsatellite data indicated the populations were made up of a high proportion of residents. The results from this study will help managers identify allopatric and sympatric breeding populations of king, clapper, and hybrid rails and aid in developing future conservation strategies.