$in = 'ARGBCTC';; $in =~ s[[^ACGT]][{A,C,G,T}]g;; print $in;; A{A,C,G,T}G{A,C,G,T}CTC print for glob $in;; AAGACTC AAGCCTC AAGGCTC AAGTCTC ACGACTC ACGCCTC ACGGCTC ACGTCTC AGGACTC AGGCCTC AGGGCTC AGGTCTC ATGACTC ATGCCTC ATGGCTC ATGTCTC