Fig. 2

Relationship of nesting between maximal matches. In each subfigure, (Aseq1, Bseq1) and (Aseq2, Bseq2) are two pairs of maximal matches; (Aseq2, Bseq2) is nested in (Aseq1, Bseq1), since either—as in subfigure (a) and (b)—or both—as in subfigure (c)—sequences of (Aseq2, Bseq2) are nested in the corresponding sequences of (Aseq1, Bseq1)