Albatross Systematics and Conservation in the Molecular Era: From the Value of Genes to the Potential of Genomes

Understanding and defining population and species units is key to protecting threatened taxa such as albatrosses, yet albatross taxonomy has been debated for more than a century. DNA sequence data has helped to resolve higher genus level taxonomy of albatrosses, but debate has persisted regarding the delineation of species. This debate is caused by disagreement over the application of species concepts, but also limitations of traditional genetic datasets to resolve closely related species pairs. Recent advances in sequencing technology have enabled rapid generation of whole-genome datasets, and analyses of these data provide more powerful and high-resolution data for assessing population structure and delineating species than traditional genetic markers. This review examines the use of DNA sequence data as applied to albatross systematics and summarizes the current knowledge for each of the four albatross genera. To date genomic data for albatrosses have mainly been generated for genus Phoebastria and have largely not been utilized to inform species-level structure and taxonomy. We conclude that whole-genome data hold promise for resolving albatross taxonomic units and informing conservation. We make suggestions for a coordinated international approach to generating whole-genome data across Diomedeidae, prioritizing populations with taxonomic uncertainties and those showing the most concerning declines.