Testing mitochondrial sequences and anonymous nuclear markers for phylogeny reconstruction in a rapidly radiating group: molecular systematics of the Delphininae (Cetacea: Odontoceti: Delphinidae)
1 NOAA Fisheries, Southeast Fisheries Science Center, 646 Cajundome Blvd. Suite 234, Lafayette, LA 70506, USA
2 University of Maryland, College of Chemical and Life Sciences, Program in Behavior, Ecology, Evolution, and Systematics, Biology-Psychology Building 1204C, College Park, MD 20742, USA
3 Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, 4210 Silver Hill Rd, Suitland, MD 20746, USA
4 National Ocean Service, 219 Fort Johnson Road, Charleston, SC 29412, USA
BMC Evolutionary Biology 2009, 9:245 doi:10.1186/1471-2148-9-245Published: 7 October 2009
Many molecular phylogenetic analyses rely on DNA sequence data obtained from single or multiple loci, particularly mitochondrial DNA loci. However, phylogenies for taxa that have undergone recent, rapid radiation events often remain unresolved. Alternative methodologies for discerning evolutionary relationships under these conditions are desirable. The dolphin subfamily Delphininae is a group that has likely resulted from a recent and rapid radiation. Despite several efforts, the evolutionary relationships among the species in the subfamily remain unclear.
Here, we compare a phylogeny estimated using mitochondrial DNA (mtDNA) control region sequences to a multi-locus phylogeny inferred from 418 polymorphic genomic markers obtained from amplified fragment length polymorphism (AFLP) analysis. The two sets of phylogenies are largely incongruent, primarily because the mtDNA tree provides very poor resolving power; very few species' nodes in the tree are supported by bootstrap resampling. The AFLP phylogeny is considerably better resolved and more congruent with relationships inferred from morphological data. Both phylogenies support paraphyly for the genera Stenella and Tursiops. The AFLP data indicate a close relationship between the two spotted dolphin species and recent ancestry between Stenella clymene and S. longirostris. The placement of the Lagenodelphis hosei lineage is ambiguous: phenetic analysis of the AFLP data is consistent with morphological expectations but the phylogenetic analysis is not.
For closely related, recently diverged taxa, a multi-locus genome-wide survey is likely the most comprehensive approach currently available for phylogenetic inference.