The Microbial Genetics and Genomics Center, Northern Arizona University, Flagstaff AZ 86011-4073, USA.
Mol Aspects Med. 2009 Dec;30(6):397-405. doi: 10.1016/j.mam.2009.08.005. Epub 2009 Sep 1.
The Bacillus anthracis genome reflects its close genetic ties to Bacillus cereus and Bacillus thuringiensis but has been shaped by its own unique biology and evolutionary forces. The genome is comprised of a chromosome and two large virulence plasmids, pXO1 and pXO2. The chromosome is mostly co-linear among B. anthracis strains and even with the closest near neighbor strains. An exception to this pattern has been observed in a large inversion in an attenuated strain suggesting that chromosome co-linearity is important to the natural biology of this pathogen. In general, there are few polymorphic nucleotides among B. anthracis strains reflecting the short evolutionary time since its derivation from a B. cereus-like ancestor. The exceptions to this lack of diversity are the variable number tandem repeat (VNTR) loci that exist in genic and non genic regions of the chromosome and both plasmids. Their variation is associated with high mutability that is driven by rapid insertion and deletion of the repeats within an array. A notable example is found in the vrrC locus which is homologous to known DNA translocase genes from other bacteria.
炭疽杆菌基因组反映了其与蜡状芽孢杆菌和苏云金芽孢杆菌的密切遗传关系，但也受到其自身独特生物学和进化力量的影响。基因组由一条染色体和两个大型毒力质粒 pXO1 和 pXO2 组成。染色体在炭疽杆菌菌株中大多是共线性的，甚至与最接近的近缘菌株也是如此。这种模式的一个例外是在一个减毒株中观察到的一个大型倒位，这表明染色体共线性对该病原体的自然生物学很重要。一般来说，炭疽杆菌菌株之间的多态性核苷酸很少，这反映了其从类似于蜡状芽孢杆菌的祖先中衍生出来的时间很短。这种缺乏多样性的例外是存在于染色体和两个质粒的基因和非基因区域的可变数串联重复 (VNTR) 位点。它们的变异与高突变率有关，这种突变率是由重复序列在一个阵列中的快速插入和缺失驱动的。一个值得注意的例子是在 vrrC 基因座中发现的，它与其他细菌中已知的 DNA 转位酶基因同源。
