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अमूर्त

Phylogeny of Different Helicobacter pylori Strains could not be Explained by 16S rRNA Gene due to High Similarity in Gene Sequence Across Strains

Wenfa Ng

Understanding the evolutionary relatedness of different strains of a species helped identify strain-specific differences that may be useful for disease diagnosis and treatment. Typically, such strain level typing would be augmented by molecular assays such as DNA sequencing, and phylogenetic tree analysis. This work utilizes public data on the 16S rRNA gene sequence of different strains of Helicobacter pylori to help plot the phylogenetic tree that describes the evolutionary trajectories of the different strains. Results from multiple sequence alignment reveals high level of conservation in 16S rRNA gene sequence across strains. This then translates into a phylogenetic tree structure that suggests very close evolutionary relationships of the different strains except for one outlier strain. Even in the case of the outlier strain, its evolutionary distance from other brethren was also not large. Overall, the results obtained in this study indicates that 16S rRNA gene may not capture strain-level phylogeny between different strains of the same species and point to efforts in elucidating this phylogenetic effect in other genes of the species. Such genes may be involved in virulence during pathogenesis in humans and may thus be subjected to higher evolutionary pressure and natural selection.