Close head-to-head juxtaposition of genes favors their coordinate regulation in Drosophila melanogaster

This report identifies a large number of gene-pairs in Drosophila melanogaster that share a common upstream region. 877 gene-pairs (-12% of the genome) are separated by less than 350 bp in a head-to-head orientation. This positional relationship is more highly favored in flies than in other organisms. These gene pairs have a higher correlation of expression than similarly spaced genes that have head-to-tail or tail-to-tail orientations. Thus, the positional arrangement of genes appears to play a significant role in coordinating relative expression patterns and may provide clues for identifying the functions of unknown genes. (C) 2004 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.