Splice junctions follow a 205-base ladder.

Of all aspects of mRNA maturation the accuracy of intervening sequence excision and exon ligation is, perhaps, the most enigmatic. Attempts to identify the essential elements involved in this process have thus far not yielded any satisfactory answer as to what structural (sequence) features are prerequisite for the vital precision of this process. In our search for underlying structural orders we asked whether exons and introns had any positional preferences within a gene. This analysis led to the unexpected discovery that the DNA length is synchronized between successive 3' splicing sites as well as between successive 5' splicing sites, with a frame of approximately 205 base pairs. This observation reveals additional organization of genes in eukaryotes and, perhaps, links gene splicing with chromatin structure.