NAG composition analysis. The histograms show the NAG composition of eukaryotic cis-splice acceptor sites (Mount 1982), of the 8929 stringently defined Ciona candidate trans-splice acceptor sites, and of the major and minor acceptor sites in 703 closely spaced major:minor pairs from the larger set of 8929 sites. Also shown, for contrast (white bars), is the NAG composition for all AGs occurring in sequences flanking the 8929 sites (±50 nt). Note the similarity of the trans-splice acceptor site NAG composition pattern to that of vertebrate cis-splice acceptor sites. The NAG composition pattern of minor sites reflected that of major sites but in a less pronounced form (see also Supplemental material, section 8).
