Slow Mitochondrial COI Sequence Evolution at the Base of the Metazoan Tree and Its Implications for DNA Barcoding
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The evolution rates of mtDNA in early metazoans hold important implications for DNA barcoding. Here, we present a comprehensive analysis of intra- and interspecific COI variabilities in Porifera and Cnidaria (separately as Anthozoa, Hydrozoa, and Scyphozoa) using a data set of 619 sequences from 224 species. We found variation within and between species to be much lower in Porifera and Anthozoa compared to Medusozoa (Hydrozoa and Scyphozoa), which has divergences similar to typical metazoans. Given that recent evidence has shown that fungi also exhibit limited COI divergence, slow-evolving mtDNA is likely to be plesiomorphic for the Metazoa. Higher rates of evolution could have originated independently in Medusozoa and Bilateria or been acquired in the Cnidaria + Bilateria clade and lost in the Anthozoa. Low identification success and substantial overlap between intra- and interspecific COI distances render the Anthozoa unsuitable for DNA barcoding. Caution is also advised for Porifera and Hydrozoa because of relatively low identification success rates as even threshold divergence that maximizes the “barcoding gap” does not improve identification success.
KeywordsInterspecific Variability Interspecific Distance Intraspecific Distance Taxon Coverage Identification Success Rate
We thank Guanyang Zhang for initial discussion and comments, as well as Gaurav Vaidya for customization of TaxonDNA for our use. Hironobu Fukami provided valuable advice on DNA extraction and PCR. We appreciate the help and support of members of the Evolutionary Biology and Marine Biology laboratories, National University of Singapore.
- Avise JC, Arnold J, Ball RM, Bermingham E, Lamb T, Neigel JE, Reeb CA, Saunders NC (1987) Intraspecific phylogeography: the mitochondrial DNA bridge between population genetics and systematics. Annu Rev Ecol Syst 18:489–522Google Scholar
- Boscolo HK, Silveira FL (2005) Reproductive biology of Palythoa caribaeorum and Protopalythoa variabilis (Cnidaria, Anthozoa, Zoanthidea) from the southeastern coast of Brazil. Brazil J Biol 65:29–41Google Scholar
- Brown WM (1983) Evolution of animal mitochondrial DNA. In: Nei M, Koehn RK (eds) Evolution of genes and proteins. Sinauer Associates, Sunderland, MA, pp 147–164Google Scholar
- Fukami H, Budd AF, Levitan DR, Jara J, Kersanach R, Knowlton N (2004a) Geographic difference in species boundaries among members of the Montastrea annularis complex based on molecular and morphological markers. Evolution 58:324–337Google Scholar
- Fukami H, Budd AF, Paulay G, Sole-Cava A, Chen CA, Iwao K, Knowlton N (2004b) Conventional taxonomy obscures deep divergence between Pacific and Atlantic corals. Nature 427:832–835Google Scholar
- Hebert PDN, Cywinska A., Ball SL, deWaard JR (2003a) Biological identifications through DNA barcodes. Proc Roy Soc Lond Ser B 270:313–321Google Scholar
- Hebert PDN, Ratnasingham S, deWaard JR (2003b) Barcoding animal life: cytochrome c oxidase subunit 1 divergences among closely related species. Proc Roy Soc Lond Ser B 270: S96–S99Google Scholar
- McClellan DA, Woolley S (2004) AlignmentHelper, version 1.0. Brigham Young University, Provo, UTGoogle Scholar
- Pont-Kingdon GA, Okada NA, Macfarlane JL, Beagley CT, Watkins-Sims CD, Cavalier-Smith T, Clark-Walker GD, Wolstenholme DR (1998) Mitochondrial DNA of the coral Sarcophyton glaucum contains a gene for a homologue of bacterial MutS: a possible case of gene transfer from the nucleus to the mitochondrion. J Mol Evol 46:419–431PubMedCrossRefGoogle Scholar
- Shearer TL, Coffroth MA (2007). Barcoding corals: limited by interspecific divergence, not intraspecific variation. Mol Ecol Resour (in press). doi: 10.1111/j.1471-8286.2007.01996.x