Abstract

Dr. Robert Drewell, Assistant Professor, Biology Department, Harvey Mudd College, California, U.S.A.

The homeotic (Hox) genes regulate segment identity during development of the embryo in all metazoans and are important in the evolution of animal morphology. The bithorax complex (BX-C) in Drosophila provides a striking example of the exquisite regulation required to direct gene expression in the developing embryo. The BX-C is over 300 kb in size, but contains only three Hox genes. The specific patterns of expression of the Hox genes during early embryonic development are controlled by an interacting network of cis-regulatory modules (CRMs), including enhancers.

We have been investigating the functional evolution of the early embryonic CRMs in the BX-C. The publication of the genomic sequences of a number of different Drosophila species has allowed us to examine the underlying evolutionary conservation of the CRMs. We applied bioinformatic approaches to perform cross-species analysis of the CRMs. The CRMs demonstrate a distinct lack of sequence conservation, suggesting that they are evolving rapidly. In our most recent studies we have tested the functional activity of the enhancer CRMs from different species in transgenic assays. In addition, we have initiated a molecular dissection of these CRMs in order to determine which sequences are necessary for the functional activity of the enhancer.

Host: Prof. Philip Ingham