Fig. 2
From: GPU accelerated sequence alignment with traceback for GATK HaplotypeCaller
An example of backtracking an optimal alignment. The backtracking of an optimal alignment starts from M6,5 (central matrix in the figure), passes through M5,4, jumps to D5,4 (right matrix in the figure), passes through D4,4, jumps to M4,4, passes through M3,3, jumps to I3,3 (left matrix in the figure), passes through I3,2, jumps to M3,2 and ends at M2,1. The optimal alignment retrieved is “MDMIM”