title: High population connectivity across the Indo-Pacific: Congruent lack of phylogeographic structure in three reef fish congeners.
abstract: We used the mitochondrial control region and a comparative approach to study the genetic population structure of two surgeonfishes, Naso brevirostris and Naso unicornis, across their Indo-central Pacific ranges. Our purpose was to compare our results with those of a previous study of Naso vlamingii [Klanten, S.O., van Herwerden, L., Choat J.H., 2007. Extreme genetic diversity and temporal rather than spatial partitioning in a widely distributed coral reef fish. Mar. Biol. 150, 659-670] another widely distributed Indo-central Pacific Naso species. We found no evidence of a barrier to gene flow between the Indian and Pacific Oceans for either species, consistent with what was shown for N. vlamingii. Overall, both target species lacked spatial population partitions and probably have complex patterns of gene flow on several spatial scales. Despite the lack of geographic population structure distinct clades were observed in N. brevirostris, similar to those found in N. vlamingii. Coalescence times for intraspecific clades of N. brevirostris and N. vlamingii approximate each other, suggesting parallel evolutionary histories. A bimodal mismatch distribution in N. brevirostris indicates that a biogeographic barrier separated N. brevirostris populations sometime during its species history. Naso unicornis, in contrast, lacked genetic structure of any kind, although it has what could represent a single surviving clade. Congruent lack of spatial population structure among all three species suggest that such patterns are not due to stochastic processes of DNA mutation and are most likely driven by ecological and environmental factors.
authors.affiliation: School of Tropical and Marine Biology, Molecular Ecology and Evolution Laboratory, James Cook University, Townsville, Qld 4811, Australia. john.horne@jcu.edu.au
authors.forename: John B
authors.initials: JB
authors.lastname: Horne
authors.forename: Lynne
authors.initials: L
authors.lastname: van Herwerden
authors.forename: J Howard
authors.initials: JH
authors.lastname: Choat
authors.forename: D R
authors.initials: DR
authors.lastname: Robertson
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D004272:DNA, Mitochondrial / Q000235:genetics; D005260:Female; D051456:Gene Flow; D049810:Genetic Speciation; D014644:Genetic Variation; D005828:Genetics, Population; D005843:Geography; D016013:Likelihood Functions; D008390:Markov Chains; D008928:Mitochondria / Q000235:genetics; D008957:Models, Genetic; D009010:Monte Carlo Method; D010140:Pacific Ocean; D010473:Perciformes / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: D004272:DNA, Mitochondrial