Genome Rearrangements Distance by Fusion, Fission, and Transposition is Easy Joao Meidanis and Zanoni Dias Given two genomes represented as circularly ordered sequences of genes, we show a polynomial time algorithm for the minimum weight series of fusion, fissions, and transpositions (with transpositions weighing twice as much as fusions and fissions) that transforms one genome into the other. The algorithm is based on classical results of permutation group theory and is the first polynomial result for a genome rearrangement problem involving transpositions. It has been observed in real biological instances that transpositions occur with about half the frequency of reversals. Although we are not using reversals in this study, this observation motivated the double weight assigned to transpositions.