Broad phylogenomic sampling improves resolution of the animal tree of life (original) (raw)

Phylogeny of Animals: Genomes Have a Lot to Say

Multiple lines of evidence have been proposed to resolve the tree of metazoans. Views based on morphology and development were often questioned because they relied on characters whose evolutionary orientation is difficult. Molecules offer an independent perspective and the employment of some genes, such as ribosomal RNA subunits (SSU/LSU) or Hox genes, have led to a profound reshaping of the metazoan tree, leading to the “New View” of animal phylogeny. However, classical molecular approaches have not succeeded in settling some long-standing issues in animal relationships. Recently, extensive genome data have been collected for a large set of organisms including several evolutionarily relevant marine species. This has allowed the development of phylogenomic approaches, which have the potential to overcome the limitations of single-gene phylogenies by inferring trees on the base of whole genome evidence. This new approach has triggered several advances regarding metazoan relationships such as the reevaluation of chordate relationships and the re-positioning of some problematic minor phyla with improved accuracy. These studies have also raised new questions about the processes that underlie morphological evolution, as well as the future of molecular phylogenetics.