Fu Jing, Qin Qi-Wei
Key Laboratory of Marine Bio-resources Sustainable Utilization, South China.
Yi Chuan. 2012 Jun;34(6):765-72. doi: 10.3724/sp.j.1005.2012.00765.
A pan-genome describes the full complement of genes in species. It is a superset of all the genes in all the individuals of a species, which is composed of a 'core genome' containing genes present in all individuals, and a 'dispensable genome' containing genes present only in some individuals and individual-specific genes. From pan-genome sight, 30 finished genomes from Escherichia coli were employed to analyze their gene and genome compositions and evaluation in this study. The results indicated that the core genes accounted for about 50% of the total number of genes, while about 146 strain-specific genes existed in the each strain tested. The data suggests that the E. coli pan-genome is vast, and unique genes will continue to be identified when more E. coli genomes are sequenced. After analyzing relationships of the gene conservation, GC content and selection pressure in different strains tested, we found that more conserved genes had a nar-row range of GC content, and they also bear more selection pressure. These results will be helpful for better understanding of the evolution profile of E. coli genome, and the dynamic changes of its gene compositions. The E. coli pan-genome pro-vides useful information for prevention and control of the diseases caused by pathogenic E. coli, and also provides a para-digm for the large-scale analysis of pathogenic bacteria genomes.
泛基因组描述了物种中基因的全部组成。它是一个物种所有个体中所有基因的超集，由所有个体中都存在的基因组成的“核心基因组”和仅在某些个体中存在的基因以及个体特异性基因组成的“可 dispensable 基因组”构成。从泛基因组的角度来看，本研究采用了 30 个已完成测序的大肠杆菌基因组来分析它们的基因和基因组组成并进行评估。结果表明，核心基因约占基因总数的 50%，而在所测试的每个菌株中大约存在 146 个菌株特异性基因。数据表明大肠杆菌泛基因组非常庞大，当对更多大肠杆菌基因组进行测序时，将继续发现独特的基因。在分析了所测试的不同菌株中基因保守性、GC 含量和选择压力之间的关系后，我们发现保守性更高的基因具有较窄的 GC 含量范围，并且它们也承受着更大的选择压力。这些结果将有助于更好地理解大肠杆菌基因组的进化概况及其基因组成的动态变化。大肠杆菌泛基因组为致病性大肠杆菌引起的疾病的预防和控制提供了有用信息，也为病原菌基因组的大规模分析提供了一个范例。
