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Marine Biology

, Volume 136, Issue 5, pp 871–879 | Cite as

Is Syllis gracilis (Polychaeta: Syllidae) a species complex? An allozyme perspective

  • F. Maltagliati
  • A. P. Peru
  • M. Casu
  • F. Rossi
  • C. Lardicci
  • M. Curini-Galletti
  • A. Castelli

Abstract

The genetic relationships between morphologically indistinguishable marine and brackish populations of Syllis gracilis Grube, 1840 (Polychaeta: Syllidae) were studied by means of allozyme electrophoresis. Samples of S. gracilis from marine coastal and brackish-water habitats were examined for variation at 13 presumptive loci. In addition, a sample of the closely related species S. prolifera (Krohn, 1852) was analysed. Five loci were multiallelic in at least one population of S. gracilis and eight loci in S. prolifera. Low to moderate levels of within-population genetic variability were found, with average expected heterozygosity values ranging from H = 0.068 (±0.043 SE) to 0.187 (±0.069 SE) in the populations of S. gracilis; higher values were found in S. prolifera (H = 0.325 ± 0.076). The presence of various private alleles indicated a marked genetic divergence among populations of S. gracilis, with Nei's genetic distances ranging from D = 0.000 to 0.833 and a highly significant F ST value. Furthermore, evidence for strong genetic heterogeneity between two sympatric marine populations was found. UPGMA cluster analysis and multidimensional scaling pointed out a clear genetic divergence between brackish and marine populations. At least two genetically divergent entities occurred in marine and brackish habitats. This could be due to local adaptation of individuals coming from marine populations to brackish habitats, but more presumably to the occurrence of a species complex within S. gracilis.

Keywords

Genetic Distance Polychaeta Multidimensional Scaling Local Adaptation Species Complex 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • F. Maltagliati
    • 1
  • A. P. Peru
    • 1
  • M. Casu
    • 1
  • F. Rossi
    • 2
  • C. Lardicci
    • 3
  • M. Curini-Galletti
    • 1
  • A. Castelli
    • 1
  1. 1.Dipartimento di Zoologia e Antropologia Biologica, Università di Sassari, Corso Margherita di Savoia 15, I-07100 Sassari, ItalyIT
  2. 2.Dipartimento di Biologia Animale, Università di Modena, Via dell'Università, 4, I-41100 Modena, ItalyIT
  3. 3.Dipartimento di Scienze dell'Uomo e dell'Ambiente, Università di Pisa, Via Volta 6, I-56126 Pisa, ItalyIT

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