Figure 6.

Possible mechanisms in which mismatched nucleotides at the 3′-OH end contribute to the formation of a dimer of primer dimer. Template DNA and primer DNA are shown in blue and green, respectively. A 3′-OH mismatched nucleotide on a primer is in red. In model (i), formation of an editing complex consisting of a template, a primer, and DNA polymerase (shown in brown) increases the likehood that a polymerase will juxtapose a 5′-OH end of one template and a 3′-OH end of another template. In model (ii), a putative repair mode of enzyme (shown in light brown) is postulated that could catalyze both editing and nonhomologous recombination more efficiently than the standard mode of polymerase action. In both cases, DNA polymerase synthesizes repeated units on templates that have phosphate breakage (indicated by GAP) to result in end-joining of a primer dimer unit.