Fraser C M, Casjens S, Huang W M, Sutton G G, Clayton R, Lathigra R, White O, Ketchum K A, Dodson R, Hickey E K, Gwinn M, Dougherty B, Tomb J F, Fleischmann R D, Richardson D, Peterson J, Kerlavage A R, Quackenbush J, Salzberg S, Hanson M, van Vugt R, Palmer N, Adams M D, Gocayne J, Weidman J, Utterback T, Watthey L, McDonald L, Artiach P, Bowman C, Garland S, Fuji C, Cotton M D, Horst K, Roberts K, Hatch B, Smith H O, Venter J C
Institute for Genomic Research, Rockville, Maryland 20850, USA.
Nature. 1997 Dec 11;390(6660):580-6. doi: 10.1038/37551.
The genome of the bacterium Borrelia burgdorferi B31, the aetiologic agent of Lyme disease, contains a linear chromosome of 910,725 base pairs and at least 17 linear and circular plasmids with a combined size of more than 533,000 base pairs. The chromosome contains 853 genes encoding a basic set of proteins for DNA replication, transcription, translation, solute transport and energy metabolism, but, like Mycoplasma genitalium, it contains no genes for cellular biosynthetic reactions. Because B. burgdorferi and M. genitalium are distantly related eubacteria, we suggest that their limited metabolic capacities reflect convergent evolution by gene loss from more metabolically competent progenitors. Of 430 genes on 11 plasmids, most have no known biological function; 39% of plasmid genes are paralogues that form 47 gene families. The biological significance of the multiple plasmid-encoded genes is not clear, although they may be involved in antigenic variation or immune evasion.
莱姆病的病原体——伯氏疏螺旋体B31的基因组包含一条由910,725个碱基对组成的线性染色体，以及至少17个线性和环状质粒，其总大小超过533,000个碱基对。该染色体含有853个基因，编码用于DNA复制、转录、翻译、溶质转运和能量代谢的一组基本蛋白质，但与生殖支原体一样，它不包含细胞生物合成反应的基因。由于伯氏疏螺旋体和生殖支原体是远缘相关的真细菌，我们认为它们有限的代谢能力反映了从代谢能力更强的祖先通过基因丢失而发生的趋同进化。在11个质粒上的430个基因中，大多数基因的生物学功能未知；39%的质粒基因是形成47个基因家族的旁系同源物。多个质粒编码基因的生物学意义尚不清楚，尽管它们可能参与抗原变异或免疫逃避。
