Mutation rate estimation

During the germinal center reaction, mutations are introduced in the variable region of the B cell receptor gene. Besides being so localized, mutations are also orders of magnitude more frequent than would be expected for a random gene in evolution. Exactly how much more frequent is difficult to estimate, because successive rounds of antigen-based selection may take place (). Accurate estimation of mutation rates becomes essential for perturbation experiments that are designed to clarify the role of various genetic elements (such as promoter or enhancer regions) on somatic hypermutation.