We implemented a software tool called GENESIS for three different genome rearrangement problems: Sorting a unichromosomal genome by weighted reversals and transpositions (SwRT), sorting a multichromosomal genome by reversals, translocations, fusions and fissions (SRTl), and sorting a multichromosomal genome by weighted reversals, translocations, fusions, fissions and transpositions (SwRTTl).