細菌ゲノムシークエンス

Bacteria exhibit unique biological characteristics at species or strain levels, and it has become possible to understand their diversities by analyzing whole genome sequences. Almost ２００ bacterial genome sequences have so far been published, and determination of the complete genomes of nearly５００bacteria is now in progress. Developments in sequencing technology and improvements in automated sequencers have contributed to the rapid accumulation of genome sequence data.
Comparative analysis of bacterial genomes has revealed that there are extensive diversities in their structures such as linear chromosomes of Borrelia burgdorferi and two chromosomes of the genus Vibrio. The diversities have been established by a combination of horizontal gene transfer, gene duplication, deletion, and/or genomic rearrangements during the process of adaptation over a long period to each environment. These changes in bacterial genomes, especially in pathogenic bacteria, are related to the occurrence of novel types of infection or multi‐drug resistance. On the other hand, genomic analysis of a gut commensal, Bacteroides fragilis, has revealed that this species dynamically changes the genomic structure within a short period of time by multiple DNA inversions that create diverse surface antigenicities to evade the host immune system. Thus, whole genome sequencing provides important information on adaptation strategies of each bacterium. However, in an environmental ecosystem such as soil, water, and human microflora, a large number of bacteria interact with each other and comprise a functional unit. Community genomics, which targets all of the bacterial genome sequences included in a particular environmental ecosystem, is expected to provide novel insights into microbe‐microbe and hostmicrobe interactions.

四国医学雑誌 : http://www.tokushima-u.ac.jp/med/research/shikoku_acta_medica.html