Section: New Results

Gene fusion and fission events

Participants : David James Sherman, Pascal Durrens [ correspondant ] , Macha Nikolski, Razanne Issa.

One consequence of genome remodelling in evolution is that these large-scale events can modify genes on the periphery of the duplicated or displaced segment, either by fusion with other genes, or by fission of a gene into several parts. These events produce radical changes in gene content, compared to the more progressive modifications produced by nucleotide substitution, and induce non-treelike, reticulate relations between genes. We have developed a novel algorithmic method for large-scale detection of gene fusion and fission events in fungal genomes, that explicitly uses relations between groups of paralogous genes in order to compensate for genome redundancy. By tracking the mathematical relations between groups of similar genes, rather than between individual genes, we can paint a global picture of remodelling across many species simultaneously. Indeed, fusion and fission events are landmarks of random remodelling, independent of mutation rate: they define a metric of “recombination distance.” This distance lets us build a genome evolution history of species and may well be a better measure than mutation distance of the process of adaptation.