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Geographical isolation in hot spring cyanobacteria
Author(s) -
Papke R. Thane,
Ramsing Niels B.,
Bateson Mary M.,
Ward David M.
Publication year - 2003
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1046/j.1462-2920.2003.00460.x
Subject(s) - biology , lineage (genetic) , biological dispersal , internal transcribed spacer , phylogenetic tree , allopatric speciation , isolation by distance , evolutionary biology , genetic diversity , hot spring , ecology , genetics , genetic structure , genetic variation , gene , population , paleontology , demography , sociology
Summary It has been proposed that free‐living microorganisms exhibit ubiquitous dispersal, do not form geographically isolated populations and rarely (if ever) speciate via allopatry. We studied island‐like hot spring cyanobacterial communities in which geographical isolation should be prominent and detectable if it influences the evolution of bacteria. The genetic diversity of cyanobacteria indigenous to North American, Japanese, New Zealand and Italian springs was surveyed by (i) amplification and cloning of 16S rRNA and 16S−23S internal transcribed spacer regions; (ii) lineage‐specific oligonucleotide probing (used to verify the predominance of cloned sequences); and (iii) lineage‐specific polymerase chain reaction (PCR) (used to search for possible rare genotypes). Phylogenetic and distribution patterns were found to be consistent with the occurrence of geographical isolation at both global and local spatial scales, although different cyanobacterial lineages were found to vary in their distribution. A lack of correspondence between biological patterning and the chemical character of springs sampled suggested that the geographical distribution of thermophilic cyanobacteria cannot be explained by the 20 potential niche‐determining chemical parameters that we assayed. Thus, geographical isolation (i.e. genetic drift) must in part be responsible for driving the observed evolutionary divergences. Geographical isolation may be an important underestimated aspect of microbial evolution.