Widespread homologous recombination within and between Streptomyces species
Widespread homologous recombination within and between Streptomyces species
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DOI：
10.1038/ismej.2010.45
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发表时间：
2010-09-01
期刊：
影响因子：
11
通讯作者：
Buckley, Daniel H.
中科院分区：
文献类型：
--
作者：
Doroghazi, James R.;Buckley, Daniel H.
水平基因转移（HGT）在微生物界广泛存在，但其对微生物物种起源和持久性的影响尚不清楚。HGT既可以获得新的遗传物质，也可以导致现有基因的同源替代。一个群体中同源重组的进化意义可以通过检测重组（rho）和突变（theta(w)）引入多态性的相对比率来量化。利用多位点序列分析（MLSA）对土壤中普遍存在的多细胞革兰氏阳性菌链霉菌的种内和种间同源重组进行了定量分析，这些细菌是抗生素和生物活性化合物的重要来源。利用从跨越1000公里的5个地点的土壤中分离的黄灰链霉菌菌株，研究了种内重组。在所检测的基因座中，菌株的核苷酸同源性为99.8%。结果表明，黄花楸内存在显著的基因交换水平（rho/theta(w) = 27.9），种群处于连锁平衡（标准化关联指数= 0.0018），存在自由重组的有性种群结构。我们还在MLSA数据集中研究了不同链霉菌物种间的同源重组，发现40%的物种具有通过HGT获得的管家基因。这些已命名物种之间的重组率（rho/theta(w) = 0.21）超过了在许多细菌物种中观察到的重组率。尽管链霉菌属中存在广泛的基因交换，但种内重组率超过种间重组率两个数量级，这表明基因交换和重组的模式可能影响了链霉菌的进化。ISME学报（2010）4,1136-1143；doi: 10.1038 / ismej.2010.45;2010年4月15日在线发布
Horizontal gene transfer (HGT) is widespread in the microbial world, but its impact on the origin and persistence of microbial species remains poorly defined. HGT can result in either acquisition of new genetic material or homologous replacement of existing genes. The evolutionary significance of homologous recombination in a population can be quantified by examining the relative rates at which polymorphisms are introduced from recombination (rho) and mutation (theta(w)). We used multilocus sequence analysis (MLSA) to quantify both intraspecies and interspecies homologous recombination among streptomycetes, multicellular Gram-positive bacteria ubiquitous in soil, which are an important source of antibiotics and bioactive compounds. Intraspecies recombination was examined using strains of Streptomyces flavogriseus isolated from soils at five locations spanning 1000 km. The strains had >99.8% nucleotide identity across the loci examined. We found remarkable levels of gene exchange within S. flavogriseus (rho/theta(w) = 27.9), and found that the population was in linkage equilibrium (standardized index of association = 0.0018), providing evidence for a freely recombining sexual population structure. We also examined interspecies homologous recombination among different Streptomyces species in an MLSA data set and found that 40% of the species had housekeeping genes acquired through HGT. The recombination rate between these named species (rho/theta(w) = 0.21) exceeds that observed within many species of bacteria. Despite widespread gene exchange in the genus, the intraspecies recombination rate exceeded the interspecies rate by two orders of magnitude suggesting that patterns of gene exchange and recombination may shape the evolution of streptomycetes. The ISME Journal (2010) 4, 1136-1143; doi: 10.1038/ismej.2010.45; published online 15 April 2010