St Jean A, Charlebois R L
Department of Biology, University of Ottawa, Canada.
J Bacteriol. 1996 Jul;178(13):3860-8. doi: 10.1128/jb.178.13.3860-3868.1996.
Anonymous probes from the genome of Halobacterium salinarium GRB and 12 gene probes were hybridized to the cosmid clones representing the chromosome and plasmids of Halobacterium salinarium GRB and Haloferax volcanii DS2. The order of and pairwise distances between 35 loci uniquely cross-hybridizing to both chromosomes were analyzed in a search for conservation. No conservation between the genomes could be detected at the 15-kbp resolution used in this study. We found distinct sets of low-copy-number repeated sequences in the chromosome and plasmids of Halobacterium salinarium GRB, indicating some degree of partitioning between these replicons. We propose alternative courses for the evolution of the haloarchaeal genome: (i) that the majority of genomic differences that exist between genera came about at the inception of this group or (ii) that the differences have accumulated over the lifetime of the lineage. The strengths and limitations of investigating these models through comparative genomic studies are discussed.
来自盐沼盐杆菌GRB基因组的匿名探针和12个基因探针与代表盐沼盐杆菌GRB和沃氏嗜盐碱杆菌DS2染色体及质粒的黏粒克隆进行杂交。分析了35个在两条染色体上均能独特交叉杂交的位点的顺序及两两之间的距离，以寻找保守性。在本研究使用的15kbp分辨率下，未检测到基因组之间的保守性。我们在盐沼盐杆菌GRB的染色体和质粒中发现了不同的低拷贝数重复序列集，表明这些复制子之间存在一定程度的分隔。我们提出了嗜盐古菌基因组进化的两种可能途径：（i）属间存在的大多数基因组差异在该类群起源时就已产生；（ii）这些差异是在该谱系的生存过程中积累的。讨论了通过比较基因组研究来探究这些模型的优势和局限性。
