A study of genetic recombination and lateral gene transfer in the order thermotogales

Comparative analyses of pathogenic bacterial genomes reveal significant levels of variation in gene content. Analysis has shown that strains of organisms thought to be of the same ¿species¿ (such as Escherichia coli strains K12 and O157) can contain anywhere from 6 ¿ 25% strain-specific genes. This diversity was long thought to be a function of the pathogenic lifestyle; however, it is more a result of evolutionary or ecological adaptations, both in pathogens and non-pathogens alike. Using a large strain collection of one bacterial order, we will examine fine-scale genetic variation and rearrangement for a number of closely related bacterial strains. Our collection comprises 18 closely related strains from the order Thermotogales, a group of non-pathogenic, mainly hyperthermophilic organisms. The type strain, Thermotoga maritima MSB8, has been completely sequenced and serves as the reference point for our studies. Previous work has demonstrated that approximately 20% of the genes in Thermotoga sp. RQ2, a close relative, are not present in the sequenced genome of T. maritima MSB8, although the two strains differ by only 0.3% in the 16S rRNA sequence, and that many of these genes seem to be required for adaptation of T. sp. RQ2 to its environment. The proposed study will examine members of this strain collection at several conserved genes, both informational and operational. Development of this alternative method to compare microbial genetics will allow researchers to gain a large amount of information much faster and more efficiently than complete genome sequencing of the same or even a smaller number of strains. With these tools we can swiftly analyze larger populations of microorganisms that can pose a threat to human health and welfare.