Figure 5

Experimental set-up to determine the effect of intron presence on the ancientness of the sequence it is in. A. The number of identical splice site residues was varied between 2 (one residue on both sides of the intron position) to 10 (2*5). The maximum number of 10 represents then a perfect match of 10 residues around a splice site. As an indication of sequence ancientness, the number of matching residues further up- and downstream was calculated. The maximum number that can be reached is 20 (10 on each side) representing a perfect match in this region. B. Control situation that described the setup with identical parameters but without an intron. All sequence comparisons in this control were thus performed relative to a virtual splice site (intron position). C. Example sequences that have respectively 1, 2, 3, 4 and 5 fixed identical sequences at each end of their splice site (in red). The fixed identical sequences around the splice site are shown in bold red. Identical residues further up- and downstream of the splice site that are used to determine general homology of the sequences are shown in bold black characters. D. Similar results as in C, using sequences without a splice site. Shown are sequences with 6 and 10 identical residues around the virtual splice site.