I've been googling and thus become aware that to estimate effective transcript lengths (as part of rna expression analyses), one should use a weighted average of the lengths of a gene's many transcript isoforms. But for the life of me I can't find a site that houses this relative isoform abundance information. I have the RefSeq transcriptome ready, but it has only the isoforms, not their (average/approximate)relative abundances. What do I do?
Big thanks in advance!