Mitochondrial DNA variation and cryptic speciation within the free-living marine nematode Pellioditis marina

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MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 300:91-103 (2005) - doi:10.3354/meps300091 Mitochondrial DNA variation and cryptic speciation within the free-living marine nematode Pellioditis marina S. Derycke1,4,*, T. Remerie1,4, A. Vierstraete2,4, T. Backeljau3, J. Vanfleteren2,4, M. Vincx1, T. Moens1 1Department of Biology, Marine Biology Section, Ghent University, Krijgslaan 281, S8, 9000 Ghent, Belgium2Department of Biology, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium3Royal Belgian Institute of Natural Sciences, Vautierstraat 29, 1000 Brussels, Belgium4CeMoFE, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium *Present address: Krijgslaan 281 Email: s.derycke@ugent.be ABSTRACT: An inverse correlation between dispersal ability and genetic differentiation among populations of a species is frequently observed in the marine environment. We investigated the population genetic structure of the free-living marine nematode Pellioditis marina. A total of 426 bp of the mitochondrial cytochrome oxidase subunit 1 (COI) gene were surveyed on a geographical scale of approximately 100 km during spring 2003. Nematodes were collected from 2 coastal locations in Belgium, and from 2 estuaries and a saltwater lake (Lake Grevelingen) in The Netherlands. Molecular variation was assessed with the single-strand conformation polymorphism (SSCP) method. In total, 32 different haplotypes were observed, and sequence divergence among 452 individuals ranged from 0.2 to 10.6%. We discovered 4 distinct mitochondrial lineages, with low divergences within the lineages (0.2 to 1.6%) and high divergences between the lineages (5.1 to 10.6%). The nuclear ribosomal ITS (internal transcribed spacer) region showed concordant phylogenetic patterns, suggesting that nematode species diversity may be considerably underestimated. Analysis of molecular variance (AMOVA) indicated a strong genetic differentiation among populations. The Lake Grevelingen population was clearly differentiated from all other populations, but genetic structuring was also significant within the Westerschelde and was correlated with gradients in salinity and pollution. The observed population genetic structure is in accordance with the limited active dispersal capacity of P. marina, but is at variance with its significant potential for passive dispersal. We therefore suggest that autecological characteristics, including short generation time, high colonization potential and local adaptation, may be at the basis of this nematode’s population genetic structure. KEY WORDS: Pellioditis marina · Single-strand conformation polymorphism · Cryptic species · Population genetic structure Full text in pdf format Supplementary Appendix PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 300. Online publication date: September 16, 2005 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2005 Inter-Research.