Heikki, Have made suggested changes to Bio::CodonUsage::Table, Bio::CodonUsage::IO and Bio::DB::CUTG and CVSd them. Richard -- Dr Richard Adams Bioinformatician, Psychiatric Genetics Group, Medical Genetics, Molecular Medicine Centre, Western General Hospital, Crewe Rd West, Edinburgh UK EH4 2XU Tel: 44 131 651 1084 richard.adams at ed.ac.uk