Differing levels of genetic divergence among atlantic and pacific mussels and their related commensal polychaetes Branchypolynoe using rDNA neutral ITS markers
Comtet, T.; Jollivet, D. (1997). Differing levels of genetic divergence among atlantic and pacific mussels and their related commensal polychaetes Branchypolynoe using rDNA neutral ITS markers, in: Biologie des sources hydrothermales profondes = Biology of deep-sea hydrothermal vents: Journées d'échanges du Programme DORSALES = DORSALES Workshop Roscoff 6-8 octobre 1997. Cahiers de Biologie Marine, 38(2): pp. 119-120
In: (1997). Biologie des sources hydrothermales profondes = Biology of deep-sea hydrothermal vents: Journées d'échanges du Programme DORSALES = DORSALES Workshop Roscoff 6-8 octobre 1997. Cahiers de Biologie Marine, 38(2)[s.n.][s.l.]. 111-149 pp., more
In: Cahiers de Biologie Marine. Station Biologique de Roscoff: Paris. ISSN 0007-9723; e-ISSN 2262-3094, more
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| Abstract |
Deep-sea hydrothermal vent mussels belonging to the genus Bathymodiolus and their related commensal polychaetes Branchipolynoe form large associations in many diffuse venting areas occurring along ridges of the eastern and western Pacific and the Atlantic. Although being morphologically diversified (von Cosel et al., 1994), hydrothermal vent mussels produce numerous microscopic, pelagc larvae which have the potential to be carried by water currents over large distances, and have the capacity to settle over a various set of habitats. In contrast, the genus Branchipolynoe, restricted to the mussel's mantle cavity, exhibits reproductive features (females have a low fecundity and produce large oocytes) that strongly suggest restricted dispersal capabilities and displays a low number of species (Miura & Hashimoto, 1991). Such contrasting ecological and biological features raise questions about the co-evolution of these two taxa and the influence of both the reproductive strategy and the geological discontinuities (as the result of the rift dynamics) on species'divergence rates. The aim of this study was to use neutral markers such as the ribosomal transcribed spacers ITS, which are known to display high substitution rates for identifying closely-related species of the bivalve-polychaete association along fast-(East Pacific Rise) and slow- (mid-Atlantic Ridge) spreading centres. This investigation showed that the polychaete Branchipolynoe diverged more rapidly than its host Bathymodiolus. Moreover, Atlantic polychaete populations are more genetically differentiated than those of the mussels. These differences are probably due to the fact that these taxa exhibit contrasting dispersal strategies, planktonotrophy allowing mussels to colonize their habitat at a wider spatial scale, or distinct generation time. On the other hand, mussel isolation between Atlantic and Pacific appears to be recent and seems to be correlated with the closing of the Panama seaway. |
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