Monterey Bay Aquarium Research Institute



Robert C. Vrijenhoek
Senior Scientist

Monterey Bay Aquarium Research Institute
7700 Sandholdt Road
Moss Landing, CA 95039
Phone: (831) 775-1799
Fax: (831) 775-1620
email: vrijen@mbari.org

         Bythograea vrijenhoeki
                                                                                                                                            Pleijel et al. 2008
                                                                                                                                            New genus and new species: Vrijenhoeki balaenophila
                                                                                                                                            
  • Interests
  • Marine Biology, Genetics and Evolution, Conservation

  • Research
  • Studies focus on the ecological and evolutionary consequences of genetic diversity in animals and associated microbes.

    • Bone-Eating worms
    • Osedax worms were discovered living on the bones of a whale found at 2891 m depth in Monterey Bay. Osedax females grow complex roots that contain symbiotic bacteria and invade the bone marrow, on which these mouthless and gutless worms subsist. Osedax males are microscopic, and they live inside the gelatinous tubes produced by the females. Sex ratios are highly skewed with more than 25 males living in an average female's tube. MBARI press release

      Some recent papers on this topic include:

      Vrijenhoek RC, Johnson SB, Rouse GW (2009) A remarkable diversity of bone-eating worms (Osedax; Siboglinidae; Annelida). BMC Biology 7, 74 (13 pages).  Link to PDF

      Vrijenhoek, RC, Johnson, S, Rouse, GW, 2008. Bone-eating Osedax females and their "harems" of dwarf males are recruited from a common larval pool. Molecular Ecology 17, 4535-4544. Link to PDF

      Rouse GW, Goffredi SK, Vrijenhoek RC (2004) Osedax: Bone-Eating Marine Worms with Dwarf Males. Science 305: 668-671. Link to PDF.

    • Gene flow and dispersal
    • Since 1989, research has focused on gene flow and evolutionary relationships of organisms endemic to deep-sea hydrothermal vents and cold water seeps. Most vent-endemic invertebrates have effective modes of dispersal that maintain genetic continuity among populations distributed thousands of kilometers along mid-ocean ridge systems. For some organisms, however, structural aspects of the ridge system (large transform faults and other discontinuities such as the Easter Microplate) result in restricted gene flow or isolation among populations.

      Young, CR., Fujio, S., Vrijenhoek, RC., 2008. Directional dispersal between mid-ocean ridges: deep-ocean circulation and gene flow in Ridgeia piscesae. Molecular Ecology 17, 1718-1731. Link to PDF

      Johnson SB, Young CR, Jones WJ, Warén A, Vrijenhoek RC (2006) Migration, isolation, and speciation of hydrothermal vent limpets (Gastropoda; Lepetodrilidae) across the Blanco Transform Fault. Biological Bulletin 210: 140-157 Link to PDF

      Hurtado LA, Lutz RA, Vrijenhoek RC (2004) Distinct patterns of genetic differentiation among annelids of eastern pacific hydrothermal vents. Molecular Ecology: 13: 2603-2615  Link to PDF

    • Molecular Systematics
    • Research has focused on the the evolutionary histories of vent and seep invertebrates. Phylogenies have been generated for many of the dominant vent taxa including clams, mussels, shrimp, and tubeworms. Present evidence suggests that taxa have had relatively recent origins during the last 100 million years.

      Hilário A, Johnson SB, Cunha MR, Vrijenhoek RC (2010) High diversity of frenulates (Polychaeta: Siboglinidae) in the Gulf of Cadiz mud volcanoes: A DNA taxonomy analysis. Deep Sea Research Part I 57, 143-150.

      Johnson SB, Warén A, Vrijenhoek RC (2008) DNA barcoding of Lepetodrilus limpets reveals cryptic species. Journal of Shellfish Research 27, 43-51.

      Jones WJ, Won YJ, Maas PAY, Smith PJ, Lutz RA, Vrijenhoek RC (2006) Evolution of habitat use by deep-sea mussels. Marine Biology 148: 841-851

      Little CTS, Vrijenhoek RC (2003) Are hydrothermal vent animals living fossils? Trends in Ecology and Evolution 18: 582-588

    • Marine Symbiosis
Vertical transmission of symbiotic bacteria ensures widely dispersing hosts with suitable bacteria when colonizing chemosynthetic habitats. Deep-sea vesicomyid clams transmit their symbionts through eggs; consequently, variation in the symbiont genome is genetically coupled with variation in the host's cytoplasmically transmitted mitochondrial genome. Cytoplasmic co-transmission results in a phylogenetic pattern of co-speciation be-tween the clam host and symbiont genomes. In contrast, vestimentiferan tubeworms (fam. Siboglinidae) acquire their sulfide-oxidizing endosymbionts from the local environment, and they show no evidence for co-speciation. These transmission modes have significant demographic consequences for microbial population structure and evolution.

Won Y-J, Jones WJ, Vrijenhoek RC (2008) Absence of co-speciation between deep-sea mytilids and their thiotrophic endosymbionts. Journal of Shellfish Research 27, 129-138.

Goffredi SK, Johnson SB, Vrijenhoek RC (2007) Genetic and potential function of microbial symbionts associated with newly discovered species of Osedax polychaete worms. Applied and Environmental Microbiology 73, 2314-2323.

Vrijenhoek RC, Duhaime M, Jones WJ (2007) Subtype variation among bacterial endosymbionts of tubeworms (Anneilda: Siboglinidae) from the Gulf of California. Biological Bulletin 212, 180-184.

Asexual reproduction

      Long-term research efforts during the past 30 years have focused on the evolutionary and ecological consequences of sexual and asexual reproduction in Mexican poeciliid fish (genus Poeciliopsis). We use a variety of molecular approaches to contrast gene and genomic evolution under the recombinant and non-recombinant breeding systems found in these fish.

      Vrijenhoek RC, Parker ED (2009) Geographical parthenogenesis, general purpose genotypes and frozen niche variation. In: Lost Sex (eds. Schön I, Martens K, Van Dijk P), pp. 99-131. Springer Publications, Berlin. manuscript version

      Vrijenhoek, RC, 1998 Animal clones and diversity. Bioscience 48: 617-628.

      Vrijenhoek RC (1979) Factors affecting clonal diversity and coexistence. American Zoologist 19, 787-797.

  • Conservation Genetics
    • Several of the sexual species of Poeciliopsis are either endangered or seriously threatened. Field and experimental studies have shown that the competitive ability, disease resistance, developmental stability, growth rate, and fecundity of these fish may be compromised by losses of genetic diversity that accompany population bottlenecks, founder events, and inbreeding.

      Vrijenhoek, R. C., 1998 Conservation genetics of freshwater fish. Journal of Fish Biology 53 (Supplement A): 394-412.

Last updated: Jan. 03, 2006