Generation of Isogenic Mutant Strains of Helicobacter pylori

One important tool in the study of gene function is the construction of mutant strains. Specifically, the construction of isogenic mutant strains imparts researchers with the ability to compare a wild-type strain to a strain that is genetically identical with the exception of the gene of interest. For a bacterial species such as Helicobacter pylori , which is notorious for the genetic heterogeneity seen across isolates, comparisons between isogenic and parental strains control for the genetic variation seen between distinct isolates. This chapter details the construction of a clean gene deletion in which the entire coding region is replaced with a selectable marker. The approach detailed herein allows for the thorough investigation of gene function in the absence of confounding genetic variability.