$in = 'GTAGGGGCTGCGCGAACGCAAACCCCCGCTGCCACAAATGATCGTCGGACTGTAGAACTCTGAACGTGTAGATCTCGGTGGCCGCCGTATCATTAAAAAAA';;

( $out = reverse $in ) =~ tr[acgtACGT][tgcaTGCA];;

print $out;;
TTTTTTTAATGATACGGCGGCCACCGAGATCTACACGTTCAGAGTTCTACAGTCCGACGATCATTTGTGGCAGCGGGGGTTTGCGTTCGCGCAGCCCCTAC