GRAPHICAL ANALYSIS OF DNA-SEQUENCE STRUCTURE .3. INDICATIONS OF EVOLUTIONARY DISTINCTIONS AND CHARACTERISTICS OF INTRONS AND EXONS

A technique for graphical representation of a gene sequence on a 2D pl ot has been shown by us earlier to be able to provide considerable inf ormation on new global sequence patterns and homologies, repeated stru ctures, relative base abundances, probable evolutionary paths and evol utionary divergences, Here we report that at a more micro level the gr aphical representation reveals differences in the features of intron a nd exon segments of eukaryotic sequences. Detailed analyses of these d ifferences show that base composition and distribution of exons have t ended to become more homogeneous with evolution, whereas introns show no significant change for the classes of genes tested by this procedur e.