EST comparison indicates 38% of human mRNAs contain possible alternative splice forms

Expressed sequence tag (EST) databases represent a large volume of informat ion on expressed genes including tissue type, expression profile and exon s tructure. In this study we create an extensive data set of human alternativ e splicing. We report the analysis of 7867 non-redundant mRNAs, 3011 of whi ch contained alternative splice forms (38% of all mRNAs analysed). From a t otal of 12572 ESTs 4560 different possible alternative splice forms were de tected. Interestingly, 70% of the alternative splice forms correspond to ex on deletion events with only 30% exonic insertions. We experimentally verif ied 19 different splice forms from 16 genes in a total subset of 20 studied ; all of the respective genes are of medical relevance. (C) 2000 Federation of European Biochemical Societies.