Figure 5.

Representative types of reversion mutation. Architecture of the homologous recombination (HR) gene is shown. The HR gene with a pathogenic mutation (MT) and a resultant premature stop codon due to out of frame sequences are illustrated in the upper panel. The normal function of the gene is lost as a result of the MT and resultant premature stop codon. As shown in the lower panel, true reversion MT completely restores the pathogenic MT and open reading frame (ORF), while second site deletion, either encompassing or not encompassing the pathogenic MT, mostly being flanked by short regions of DNA sequence microhomology, generates an alternative ORF with a naive stop codon, leading to a restoration of gene function.