DNA evidence for global dispersal and probable endemicity of protozoa

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DNA evidence for global dispersal and probable endemicity of protozoa

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dc.contributor.author Bass, David en_GB
dc.contributor.author Richards, Thomas A en_GB
dc.contributor.author Matthai, Lena en_GB
dc.contributor.author Marsh, Victoria en_GB
dc.contributor.author Cavalier-Smith, Thomas en_GB
dc.contributor.department University of Exeter en_GB
dc.date.accessioned 2008-09-28T21:21:50Z en_GB
dc.date.accessioned 2011-01-25T11:46:52Z en_US
dc.date.accessioned 2013-03-20T14:47:34Z
dc.date.issued 2007-09-13 en_GB
dc.description.abstract Background It is much debated whether microbes are easily dispersed globally or whether they, like many macro-organisms, have historical biogeographies. The ubiquitous dispersal hypothesis states that microbes are so numerous and so easily dispersed worldwide that all should be globally distributed and found wherever growing conditions suit them. This has been broadly upheld for protists (microbial eukaryotes) by most morphological and some molecular analyses. However, morphology and most previously used evolutionary markers evolve too slowly to test this important hypothesis adequately. Results Here we use a fast-evolving marker (ITS1 rDNA) to map global diversity and distribution of three different clades of cercomonad Protozoa (Eocercomonas and Paracercomonas: phylum Cercozoa) by sequencing multiple environmental gene libraries constructed from 47–80 globally-dispersed samples per group. Even with this enhanced resolution, identical ITS sequences (ITS-types) were retrieved from widely separated sites and on all continents for several genotypes, implying relatively rapid global dispersal. Some identical ITS-types were even recovered from both marine and non-marine samples, habitats that generally harbour significantly different protist communities. Conversely, other ITS-types had either patchy or restricted distributions. Conclusion Our results strongly suggest that geographic dispersal in macro-organisms and microbes is not fundamentally different: some taxa show restricted and/or patchy distributions while others are clearly cosmopolitan. These results are concordant with the 'moderate endemicity model' of microbial biogeography. Rare or continentally endemic microbes may be ecologically significant and potentially of conservational concern. We also demonstrate that strains with identical 18S but different ITS1 rDNA sequences can differ significantly in terms of morphological and important physiological characteristics, providing strong additional support for global protist biodiversity being significantly higher than previously thought. en_GB
dc.identifier.citation BMC Evolutionary Biology 2007 7:162 en_GB
dc.identifier.doi 10.1186/1471-2148-7-162 en_GB
dc.identifier.uri http://hdl.handle.net/10036/38242 en_GB
dc.language.iso en en_GB
dc.publisher BioMed Central en_GB
dc.relation.url http://www.biomedcentral.com/1471-2148/7/162 en_GB
dc.relation.url http://creativecommons.org/licenses/by/2.0 en_GB
dc.rights Copyright © 2007 Bass et al; licensee BioMed Central Ltd. en_GB
dc.title DNA evidence for global dispersal and probable endemicity of protozoa en_GB
dc.type Article en_GB
dc.date.available 2007-09-13 en_GB
dc.date.available 2008-09-28T21:21:50Z en_GB
dc.date.available 2011-01-25T11:46:52Z en_US
dc.date.available 2013-03-20T14:47:34Z
dc.identifier.issn 1471-2148 en_GB
dc.identifier.journal BMC Evolutionary Biology en_GB
dc.identifier.pmcid 2194784 en_GB
dc.identifier.pmid 17854485 en_GB


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