title: Molecular evolution of a widely-adopted taxonomic marker (COI) across the animal tree of life.
abstract: DNA barcodes are widely used for identification and discovery of species. While such use draws on information at the DNA level, the current amassment of ca. 4.7 million COI barcodes also offers a unique resource for exploring functional constraints on DNA evolution. Here, we explore amino acid variation in a crosscut of the entire animal kingdom. Patterns of DNA variation were linked to functional constraints at the level of the amino acid sequence in functionally important parts of the enzyme. Six amino acid sites show variation with possible effects on enzyme function. Overall, patterns of amino acid variation suggest convergent or parallel evolution at the protein level connected to the transition into a parasitic life style. Denser sampling of two diverse insect taxa revealed that the beetles (Coleoptera) show more amino acid variation than the butterflies and moths (Lepidoptera), indicating fundamental difference in patterns of molecular evolution in COI. Several amino acid sites were found to be under notably strong purifying selection in Lepidoptera as compared to Coleoptera. Overall, these findings demonstrate the utility of the global DNA barcode library to extend far beyond identification and taxonomy, and will hopefully be followed by a multitude of work.
authors.affiliation: Department of Genetics and Physiology, University of Oulu, P.O.Box 3000 (Pentti Kaiteran katu 1), FI-90014, Finland.
authors.forename: Mikko
authors.initials: M
authors.lastname: Pentinsaari
authors.affiliation: Department of Biosciences, Centre of Excellence in Biological Interactions, University of Helsinki, Viikinkaari 1, FI-00014, Finland.
authors.forename: Heli
authors.initials: H
authors.lastname: Salmela
authors.affiliation: Department of Genetics and Physiology, University of Oulu, P.O.Box 3000 (Pentti Kaiteran katu 1), FI-90014, Finland.
authors.forename: Marko
authors.initials: M
authors.lastname: Mutanen
authors.affiliation: Spatial Foodweb Ecology Group, Department of Agricultural Sciences, University of Helsinki, Latokartanonkaari 5, FI-00014, Finland.|Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, 750 07 Uppsala, Sweden.
authors.forename: Tomas
authors.initials: T
authors.lastname: Roslin
mesh_terms: D000818:Animals; D058893:DNA Barcoding, Taxonomic; D019143:Evolution, Molecular; D005819:Genetic Markers
chemical_list: D005819:Genetic Markers