Garcia-Vallvé S, Romeu A, Palau J
Rovira i Virgili University, Department of Biochemistry and Biotechnology, E-43005 Tarragona, Catalonia, Spain.
Genome Res. 2000 Nov;10(11):1719-25. doi: 10.1101/gr.130000.
There is growing evidence that horizontal gene transfer is a potent evolutionary force in prokaryotes, although exactly how potent is not known. We have developed a statistical procedure for predicting whether genes of a complete genome have been acquired by horizontal gene transfer. It is based on the analysis of G+C contents, codon usage, amino acid usage, and gene position. When we applied this procedure to 17 bacterial complete genomes and seven archaeal ones, we found that the percentage of horizontally transferred genes varied from 1.5% to 14.5%. Archaea and nonpathogenic bacteria had the highest percentages and pathogenic bacteria, except for Mycoplasma genitalium, had the lowest. As reported in the literature, we found that informational genes were less likely to be transferred than operational genes. Most of the horizontally transferred genes were only present in one or two lineages. Some of these transferred genes include genes that form part of prophages, pathogenecity islands, transposases, integrases, recombinases, genes present only in one of the two Helicobacter pylori strains, and regions of genes functionally related. All of these findings support the important role of horizontal gene transfer in the molecular evolution of microorganisms and speciation.
越来越多的证据表明，水平基因转移是原核生物中一种强大的进化力量，尽管其确切强度尚不清楚。我们已经开发出一种统计方法，用于预测完整基因组中的基因是否通过水平基因转移获得。该方法基于对G+C含量、密码子使用、氨基酸使用和基因位置的分析。当我们将此方法应用于17个细菌完整基因组和7个古细菌基因组时，我们发现水平转移基因的比例从1.5%到14.5%不等。古细菌和非致病细菌的比例最高，而除生殖支原体外的致病细菌比例最低。正如文献中所报道的，我们发现信息基因比操作基因更不容易转移。大多数水平转移基因仅存在于一两个谱系中。其中一些转移基因包括构成原噬菌体、致病岛、转座酶、整合酶、重组酶的基因、仅存在于两种幽门螺杆菌菌株之一中的基因，以及功能相关的基因区域。所有这些发现都支持水平基因转移在微生物分子进化和物种形成中的重要作用。
