Gene transfer is a major factor in bacterial evolution
Gene transfer is a major factor in bacterial evolution
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DOI：
10.1093/oxfordjournals.molbev.a025569
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发表时间：
1996-01-01
影响因子：
10.7
通讯作者：
Reeves, PR
中科院分区：
文献类型：
--
作者：
Lan, RT;Reeves, PR
已经使用基因组消减法评估了四种肠道沙门氏菌菌株中的横向基因转移。使用菌株LT 2（亚种I血清型鼠伤寒）染色体DNA作为靶标，并减去血清型鼠伤寒（S21）、Muenchen（S71）、Typhi（M229）的3个亚种I菌株和亚种V菌株（M321）。用减去后的残留LT 2 DNA的制备物探测LT 2 DNA的随机互补的数据，用于估计不能与菌株S21、S71、M229和M321杂交的LT 2 DNA的量分别在84-106、191-355、305-629和778- 1，286 kb的范围内。几条证据表明，大部分DNA来自菌株M321中不存在的基因，而不是来自序列上有分歧的基因。多位点酶电泳和管家基因序列变异显示，这与四个菌株的分歧有关。对39个来自M321消减的残留LT 2 DNA的片段进行测序，仅发现6个已知基因功能的插入片段，证明在S.肠克隆。39个片段中有16个片段的G+C含量低于45%，低于物种平均水平，但超过一半的片段在物种的正常范围内。我们的结论是，即使在一个物种内，克隆可能会有高达20%的染色体DNA的差异，表明横向转移的主要作用，并在G+C含量的基础上，一个显着比例的DNA是从远亲物种。
Lateral gene transfer in four strains of Salmonella enterica has been assessed using genomic subtraction. Strain LT2 (subspecies I serovar Typhimurium) chromosomal DNA was used as target and subtracted by three subspecies I strains of serovars Typhimurium (S21), Muenchen (S71), Typhi (M229), and a subspecies V strain (M321). Data from probing random cosmids of LT2 DNA with preparations of the residual LT2 DNA after subtraction were used to estimate the amounts of LT2 DNA not able to hybridize to strains S21, S71, M229, and M321 to be in the range of 84-106, 191-355, 305-629, and 778-1,286 kb, respectively. Several lines of evidence indicate that most of this DNA is from genes not present in strain M321 and not from genes that have diverged in sequence. The amounts correlate with the divergence of the four strains as revealed by multilocus enzyme electrophoresis and sequence variation of housekeeping genes. Sequence of 39 of the fragments from the M321 subtracted residual LT2 DNA revealed only six inserts of known gene function with evidence of both gain and loss of genes during the development of S. enterica clones. Sixteen of the 39 segments have 45% or lower G+C content, below the species average, but over half are within the normal range for the species. We conclude that even within a species, clones may differ by up to 20% of chromosomal DNA, indicating a major role for lateral transfer, and that on the basis of G+C content, a significant proportion of the DNA is from distantly related species.