Gene clusters in the fly genome

A number of studies have provided convincing evidence that co-expressed genes are often found in clusters in the yeast, fly, worm or human genomes. In the December 12 Nature, Alexander Boutanaev and colleagues describe additional examples of clustering of Drosophila genes (Nature, 420:666-669, December 12, 2002).

Analysis of available EST databases identified 4,271 testes-expressed genes, of which 1,661 appear to be testes-specific. Mapping each EST to the fly genome revealed that about one third of testes-specific genes are clustered. Many of these clusters (45%) contain four or more genes. A notable exception was chromosome X, which showed little clustering of testes-specific genes and smaller cluster sizes. Additional EST-based analysis also showed clusters of head-specific genes and embryonic genes.

Much remains to be discovered about the role of chromatin structure in the transcriptional regulation of genome clusters.