hi everybody, I wrote a program in bioperl and perl/tk. A description of this program and the program itself could be find at : http://www-iag.unice.fr/gepcr/gepcr.html i will be happy to have any feed-back , suggestions or comments about it. Damien ---------------------------- Damien Mattei C.N.R.S / U.N.S.A - UMR 6549 mailto:mattei@unice.fr http://www-iag.unice.fr/ ----------------------------