Genetic Affinities Within the Herring Gull Larus argentatus Assemblage Revealed by AFLP Genotyping

Abstract: To date, the taxonomic status of circumpo-lar breeding populations of the Herring Gull Larus ar-gentatus, the Lesser Black-backed Gull Larus fuscus, and the closely related Yellow-legged Gull Larus cach-innans has been based on differences or similarities in phenotype, morphology, and feeding and premating be-havior. To shed some new light on the many taxonomic uncertainties surrounding these taxa, we describe the re-sults of a large DNA study based on comparing the dis-tribution of 209 biallelic markers among 109 gulls, rep-resenting 11 gull taxa of the Herring Gull assemblage and the Common Gull Larus canus. A detailed phyloge-netic analysis failed to show clustering of individuals into groups representing either geographic origin or phe-notype. Alternatively, birds were grouped into taxa de-fined on the basis of phenotype and geographic origin or phenotype alone. Genetic analyses revealed significantly different genetic distances between all pairs of taxa. However, based on these genetic distances, again no con-sistent phylogenetic tree could be constructed. Analysis of molecular variance indicated that about 77 % of the total genetic variability among these gulls could be ex-plained by within-taxon differences. Only 23 % of the total genetic variability was due to genetic differences between taxa, irrespective of their species or subspecies status. Although this seems to challenge the current taxo-nomic treatment of the herring gull assemblage, our re-sults are too premature and too incomplete to recom-mend a drastic change