distribution of number of reads mapped to a union-transcript

[alittleboy]

If we consider all isoforms of a gene, and construct a "union transcript", then we can calculate the number of reads uniquely mapped to each exon of the union transcript. My question is, what is the distribution of the reads on this union transcript? If the number of exons associated in the union transcript is large (say more than 30), can we assume that the reads are normally distributed?

This may not be obvious and may depend on the gene being studies, but I am just curious if, for greater number of exons, the reads can be normally approximated.

Thanks!