Genes linked by fusion events are generally of the same functional category: A systematic analysis of 30 microbial genomes

Recent work in computational genomics has shown that a functional associati on between two genes can be derived from the existence of a fusion of the t wo as one continuous sequence in another genome. For each of 30 completely sequenced microbial genomes, we established all such fusion links among its genes and determined the distribution of links within and among 15 broad f unctional categories. We found that 72% of all fusion links related genes o f the same functional category. A comparison of the distribution of links t o simulations on the basis of a random model further confirmed the signific ance of intracategory fusion links. Where a gene of annotated function is l inked to an unclassified gene, the fusion link suggests that the two genes belong to the same functional category. The predictions based on fusion lin ks are shown here for Methanobacterium thermoautotrophicum, and another 661 predictions are available at http://fusion.bu.edu.