The types and prevalence of alternative splice forms.

The finding that eukaryotic gene structures are extremely complex prompted the development of new experimental techniques for the accurate measurement of transcription start site usage and of the expression of alternative splice forms. On the computational side, analyses of large databases of splice variants revealed differences in the length, motif composition and selection pressure between constitutive and alternatively spliced exons. Such features are being incorporated into novel computational tools for gene structure prediction. The result of these investigations is a continuously improving catalogue of alternative splice forms. How the expression of these alternative splice forms is regulated remains one of the major open questions.