Fig. 3
From: Reconstruction of ancestral RNA sequences under multiple structural constraints
Three examples of the positions that need to be considered when using information from both structures. Note that in those examples, we consider that we are working on the sequence of family 1, and fam1 and fam2 represent the 2D structures of family 1 and 2 respectively. a The easier case when the position (8 here) is not paired in fam1, and we only have to consider the position paired with it in fam2. b The case where only one of the two paired positions of fam1 is paired in fam2. c The case where both paired positions of fam1 are paired in fam2