def backUpDB() :
    """backup the current database version. automatically called by importGenome(). Returns the filename of the backup"""
    st = time.ctime().replace(' ', '_')
    fn = conf.pyGeno_RABA_DBFILE.replace('.db', '_%s-bck.db' % st)
    shutil.copy2(conf.pyGeno_RABA_DBFILE, fn)

    return fn
backup the current database version. automatically called by importGenome(). Returns the filename of the backup