Phylogenetic comparative analysis of RNA structure on Macintosh computers

A Macintosh Hypertalk program (Hypercard 'stack') for use in phylogenetic comparative analysis of RNA structure is described. The program identifies covariations and compensatory changes in RNA sequence alignments, for use in the construction of secondary structure models or the identification of tertiary interactions. The results of an analysis are presented either as a list of positions in the alignment which covary, or as a 2-dimensional matrix in which potential helices in the secondary structure appear as diagonal patterns.