Table 4.
Counting number of conserved octamers in the exonic proximity
| Intronic flanks next to 5'SS | Intronic flanks next to 3'SS | ||||
| 5'SS ISEs | 3'SS ISEs | ||||
| Conserved | Non-Conserved | Conserved | Non-Conserved | ||
| Elements | 4,024 | 6,800 | Elements | 4,272 | 8,363 |
| Non- elements |
251,842 | 518,369 | Non- elements |
261,387 | 578,106 |
| Fisher 2-tail test: 1.81 × 10-22 | Fisher 2-tail test: 1.59 × 10-10 | ||||
| 5'SS ISSs | 3'SS ISSs | ||||
| Conserved | Non- Conserved | Conserved | Non- Conserved | ||
| Element | 399 | 648 | Element | 6,537 | 11,385 |
| Non- elements |
251,842 | 518,369 | Non- elements |
261,387 | 578,106 |
| Fisher 2-tail test: 0.00025 | Fisher 2-tail test: 3.46 × 10-51 | ||||
Set of all other possible elements was obtained by excluding the ISEs and ISSs supporting either 5' or 3' SSs from the set of all possible octamers. We counted cases where oligonucleotides stay entirely conserved versus changing in at least one nucleotide position between the pairs of sequences from multiple sequence alignments, where only the motifs containing no gaps were considered. In case of 5'SS elements we considered window of size 20 nt starting 16 nt downstream from 5' exonic boundary in human sequence, where in case of elements supporting 3'SS we considered 20 nt window ending 63 nt upstream of 3' exonic boundary.