Research Summary: We are interested in the role of posttranscriptional gene regulation during vertebrate development. Specifically, we want to understand the role of alternative splicing, which has recently gained more attention since it was discovered that the human genome has fewer, 23,425, protein coding genes. This observation was quite surprising when one considers that some of the invertebrate species such as the Drosophila (Fruit fly) has 14,000 protein coding genes. Thus, with an additional 10,000 genes one can make an entire human being. This raises the question as to how humans acquire the vast proteome complexity needed to build such a complex organism from so few genes. It is here that alternative splicing plays a vital role. Alternative splicing facilitates combinatorial splicing of exons to produce multiple protein isoforms from a single gene. Indeed, most vertebrate genes are now known to be alternatively spliced. Given the extent to which the genes are alternatively spliced, we want to understand how alternative splicing is regulated during development and the impact it may have in regulating gene networks during development.