FIG. 5.

Model for partial tandem gene duplications. Events can be initiated by a DSB within a repetitive element (gray box) on one chromosome, followed by invasion of one end into the same element on the homologue or sister chromatid. Repair synthesis extends downstream to duplicate sequences, shown here as exons 2 and 3 (white bars). Completion of the repair event occurs by NHEJ of the newly synthesized strands at or near the end of the broken chromosome. The result is a partial tandem gene duplication on one chromosome or chromatid, while the other chromosome or chromatid remains unaltered.