Geographical isolation in hot spring cyanobacteria
Geographical isolation in hot spring cyanobacteria
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DOI：
10.1046/j.1462-2920.2003.00460.x
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发表时间：
2003-08-01
影响因子：
5.1
通讯作者：
Ward, DM
中科院分区：
文献类型：
--
作者：
Papke, RT;Ramsing, NB;Ward, DM
有人提出，自由生活的微生物表现出无处不在的扩散，不会形成地理上孤立的种群，并且很少（如果有的话）通过异域繁殖形成物种。我们研究了岛状温泉蓝藻群落，其中地理隔离如果影响细菌的进化，那么地理隔离应该是显着的并且是可检测的。通过 (i) 16S rRNA 和 16S-23S 内部转录间隔区的扩增和克隆，调查了北美、日本、新西兰和意大利泉水本土蓝藻的遗传多样性； (ii) 谱系特异性寡核苷酸探测（用于验证克隆序列的优势）； (iii) 谱系特异性聚合酶链式反应 (PCR)（用于寻找可能的稀有基因型）。尽管发现不同的蓝藻谱系的分布有所不同，但系统发育和分布模式与全球和局部空间尺度上地理隔离的发生一致。生物模式与泉水采样的化学特征之间缺乏对应性，这表明嗜热蓝藻的地理分布不能用我们分析的 20 个潜在的决定生态位的化学参数来解释。因此，地理隔离（即遗传漂变）一定是造成观察到的进化差异的部分原因。地理隔离可能是微生物进化中一个被低估的重要方面。
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.