DNA$="CGTAAAAAATTACAACGTCCTTTGGCTATCTCTTAAACTCCTGCTAAATG" +\
      \    "CTCGTGCTTTCCAATTATGTAAGCGTTCCGAGACGGGGTGGTCGATTCTG" +\
      \    "AGGACAAAGGTCAAGATGGAGCGCATCGAACGCAATAAGGATCATTTGAT" +\
      \    "GGGACGTTTCGTCGACAAAGTCTTGTTTCGAGAGTAACGGCTACCGTCTT" +\
      \    "CGATTCTGCTTATAACACTATGTTCTTATGAAATGGATGTTCTGAGTTGG" +\
      \    "TCAGTCCCAATGTGCGGGGTTTCTTTTAGTACGTCGGGAGTGGTATTATA" +\
      \    "TTTAATTTTTCTATATAGCGATCTGTATTTAAGCAATTCATTTAGGTTAT" +\
      \    "CGCCGCGATGCTCGGTTCGGACCGCCAAGCATCTGGCTCCACTGCTAGTG" +\
      \    "TCCTAAATTTGAATGGCAAACACAAATAAGATTTAGCAATTCGTGTAGAC" +\
      \    "GACCGGGGACTTGCATGATGGGAGCAGCTTTGTTAAACTACGAACGTAAT" + CHR$0

      @%=3      : REM Width of the print zone
      P%=!^DNA$ : REM Address of string in memory
      WHILE ?P%
        IF I% MOD 50 == 0 PRINT 'I% ": ";
        VDU ?P% : REM Output ASCII value at address P%
        CASE ?P% OF
          WHEN ASC"A" A+=1
          WHEN ASC"C" C+=1
          WHEN ASC"G" G+=1
          WHEN ASC"T" T+=1
        ENDCASE
        I%+=1
        P%+=1
      ENDWHILE
      PRINT '' "A: " A ' "C: " C  ' "G: " G ' "T: " T
      PRINT "Total: " A + C + G + T