Deep RNA sequencing has emerged as a powerful technology for transcriptome analysis. By generating massive amount of short sequence reads from a given RNA sample, one can use RNA-Seq to define and quantify patterns of gene expression and RNA processing on a genomic scale. This project will develop methods for analysis of transcriptome complexity (gene expression, RNA processing, non-coding RNA) using RNA-Seq data, and apply these methods to study transcriptome regulation and mRNA isoform expression in development and disease.