Testing mitochondrial sequences and anonymous nuclear markers for phylogeny reconstruction in a rapidly radiating group: molecular systematics of the Delphininae (Cetacea: Odontoceti: Delphinidae).
BACKGROUND
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.


RESULTS
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.


CONCLUSIONS
For closely related, recently diverged taxa, a multi-locus genome-wide survey is likely the most comprehensive approach currently available for phylogenetic inference.
Kingston
Sarah E
SE
NOAA Fisheries, Southeast Fisheries Science Center, 646 Cajundome Blvd. Suite 234, Lafayette, LA 70506, USA. kingstons@si.edu
Adams
Lara D
LD
Rosel
Patricia E
PE
D054458:Amplified Fragment Length Polymorphism Analysis; D000818:Animals; D002467:Cell Nucleus / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D004289:Dolphins / Q000145:classification / Q000235:genetics*; D019143:Evolution, Molecular; D005819:Genetic Markers; D023281:Genomics / Q000379:methods*; D006824:Hybridization, Genetic; D010802:Phylogeny; D017422:Sequence Analysis, DNA
D004272:DNA, Mitochondrial; D005819:Genetic Markers