Figure 1

Experimental set-up to select putative conserved genes from an exon/intron database. A. Conserved introns were defined as i) homologous exon gene sequences that ii) shared an intron position and iii) were from different taxa that split near the root of the Eukaryotic Tree. The actual splice site sequence was derived from concatenating subsequent exons (exon x and exon x+1, where x is exon number) using SQL and performing a full database scan. B. A sequence of 10 residues around the intron position was taken (5 pre-intron and 5 post-intron) as the splice site (in red), while a further homology was determined up- and downstream of the intron (each 10 residues; in black). For a conserved intron, at least 6/10 splice site residues should match and a further 6 matching residues in the 20 residues up- and downstream. C. Example of a conserved splice site (in red) with a 8/10 splice site match (in bold) that shows more sequence homology further away from the splice site (black) since 10/20 residues (in bold) match. The sequences shown are from a protein phosphatase that is conserved between animal (human) and fungi (Schizosaccharomyces).