Encoding the cellular complexity of metozoa in their genome

Akira Chiba, Cell and Structural Biology, University of Illinois at Urbana-Champaign

Metazoan development requires mechanisms to generate cells with diverse functions. Although gene duplication increases genomic complexity, it alone is insufficient to underscore cellular diversity within organisms. Here, we combine in silico and in vivo approaches to show that the arthropod N-Cadherin gene has maintained a common promoter and sets of mutually-exclusive alternatively-spliced exons (MEs) over 400 million years and, furthermore, isoforms derived from these MEs receive separate spatiotemporal controls critical during development. Thus, alternative splicing fundamentally expands the genome's ability to generate complex yet reproducible patterns of molecular expression. Its adaptation might be tied to the evolution of metazoa.