Understanding causative relationships between specific regulatory elements and expression patterns would greatly enhance the ability to predict disease-associated genes (Pennacchio and Rubin 2003) . However, even in computational approaches the ability to identify and predict the regulatory functions of non-coding sequences has been limited (Pennacchio and Rubin 2003) . Pairwise comparisons have helped to predict functionally conserved regions, however the statistical accuracy of these predictions is increased when more than two sequences are used (Dubchak et al. 2000) . Several studies suggest that comparative analysis of multiple evolutionarily diverse organisms facilitate the prediction of functionally important non-coding regions (Dubchak et al. 2000; Matys et al. 2003; Thomas et al. 2003) . Comparisons of genome sequences from evolutionarily diverse organisms also elucidate regulatory regions that are specific to a particular species or group of species. Recent additions of the African tree frog (Xenopus tropicalis), chicken (Gallus gallus) and dog (Canis familiaris) to the sequencing pipeline will provide important complementary perspectives for tetrapods, but data from more divergent vertebrate genomes is still needed. Different rates of molecular evolution, including gene duplication, underscore the importance of the examination of genomic sequences from an evolutionary range of organisms for comparative sequence analyses. When such an approach is taken, the contrast of divergent sequences differentiates between functionally conserved regions and generally conserved regions that simply reflect a lack of divergence time (Dubchak et al. 2000) . Using sequences from evolutionarily diverse organisms may provide the necessary divergence to identify functionally conserved regions in genes that have evolved slowly.