package jalview.schemes;
import java.util.*;
+import java.util.List;
import java.awt.*;
codonHash.put("STOP", STOP);
}
- public static Hashtable codonHash2 = new Hashtable();
+ /**
+ * Nucleotide Ambiguity Codes
+ */
+ public static final Hashtable<String,String[]> ambiguityCodes=new Hashtable<String,String[]>();
+ /**
+ * Codon triplets with additional symbols for unambiguous codons that include ambiguity codes
+ */
+ public static final Hashtable<String,String> codonHash2 = new Hashtable<String,String>();
+
+ /**
+ * all ambiguity codes for a given base
+ */
+ public final static Hashtable<String,List<String>> _ambiguityCodes = new Hashtable<String,List<String>>();
+
static
{
+ /**
+ * 3.2. Purine (adenine or guanine): R
+ *
+ * R is the symbol previously recommended [1].
+ */
+ ambiguityCodes.put("R", new String[]
+ { "A", "G" });
+
+ /**
+ * 3.3. Pyrimidine (thymine or cytosine): Y
+ *
+ * Y is the symbol previously recommended [1].
+ */
+ ambiguityCodes.put("Y", new String[]
+ { "T", "C" });
+ /**
+ * 3.4. Adenine or thymine: W
+ *
+ * Although several diverse symbols have been used for this pair, (and for
+ * the reciprocal pair G+C), only two symbols have a rational basis, L and
+ * W: L derives from DNA density (light; G+C - heavy - would thus be H); W
+ * derives from the strength of the hydrogen bonding interaction between the
+ * base pairs (weak for A+T: G +C - strong - would thus be S). However, the
+ * system recommended for the three-base series (not-A = B, etc., see below,
+ * section 3.8) rules out H as this would be not-G. W is thus recommended.
+ */
+ ambiguityCodes.put("W", new String[]
+ { "A", "T" });
+ /**
+ * 3.5. Guanine or cytosine: S
+ *
+ * The choice of this symbol is discussed above in section 3.4.
+ */
+ ambiguityCodes.put("S", new String[]
+ { "G", "C" });
+ /**
+ * 3.6. Adenine or cytosine: M
+ *
+ * There are few common features between A and C. The presence of an NH2
+ * group in similar positions on both bases (Fig. 1) makes possible a
+ * logically derived symbol. A and N being ruled out, M (from aMino) is
+ * recommended.
+ *
+ *
+ * Fig. 1. Origin of the symbols M and K The four bases are drawn so as to
+ * show the relationship between adenine and cytosine on the one hand, which
+ * both have aMino groups at the ring position most distant from the point
+ * of attachment to the sugar, and between guanine and thymine on the other,
+ * which both have Keto groups at the corresponding position. The ring atoms
+ * are numbered as recommended [24-26], although for the present purpose
+ * this has the disadvantage of giving discordant numbers to the
+ * corresponding positions.
+ */
+ ambiguityCodes.put("M", new String[]
+ { "A", "C" });
+ /**
+ * 3.7. Guanine or thymine: K By analogy with A and C (section 3.6), both G
+ * and T have Keto groups in similar positions (Fig. 1).
+ */
+ ambiguityCodes.put("K", new String[]
+ { "G", "T" });
+ /**
+ * 3.8. Adenine or thymine or cytosine: H
+ *
+ * Not-G is the most simple means of memorising this combination and symbols
+ * logically related to G were examined. F and H would both be suitable, as
+ * the letters before and after G in the alphabet, but A would have no
+ * equivalent to F. The use of H has historical precedence [2].
+ */
+ ambiguityCodes.put("H", new String[]
+ { "A", "T", "C" });
+ /**
+ * 3.9. Guanine or cytosine or thymine: B
+ *
+ * Not-A as above (section 3.8).
+ */
+ ambiguityCodes.put("B", new String[]
+ { "G", "T", "C" });
+ /**
+ * 3.10. Guanine or adenine or cytosine: V
+ *
+ * Not-T by analogy with not-G (section 3.8) would be U but this is ruled
+ * out to eliminate confusion with uracil. V is the next logical choice.
+ * Note that T and U may in some cases be considered to be synonyms.
+ */
+ ambiguityCodes.put("V", new String[]
+ { "G", "A", "C" });
+ /**
+ * 3.11. Guanine or adenine or thymine: D
+ *
+ * Not-C as above (section 3.8).
+ */
+ ambiguityCodes.put("D", new String[]
+ { "G", "A", "T" });
+ /**
+ * 3.12. Guanine or adenine or thymine or cytosine: N
+ */
+ ambiguityCodes.put("R", new String[]
+ { "G", "A", "T", "C" });
+ // Now build codon translation table
codonHash2.put("AAA", "K");
codonHash2.put("AAG", "K");
codonHash2.put("AAC", "N");
codonHash2.put("TTC", "F");
codonHash2.put("TTT", "F");
+
+ buildAmbiguityCodonSet();
+ }
+
+ /**
+ * programmatic generation of codons including ambiguity codes
+ */
+ public static void buildAmbiguityCodonSet()
+ {
+ if (_ambiguityCodes.size() > 0)
+ {
+ System.err
+ .println("Ignoring multiple calls to buildAmbiguityCodonSet");
+ return;
+ }
+ // Invert the ambiguity code set
+ for (Map.Entry<String, String[]> acode : ambiguityCodes.entrySet())
+ {
+ for (String r : acode.getValue())
+ {
+ List<String> codesfor = _ambiguityCodes.get(r);
+ if (codesfor == null)
+ {
+ _ambiguityCodes.put(r, codesfor = new ArrayList<String>());
+ }
+ if (!codesfor.contains(acode.getKey()))
+ {
+ codesfor.add(acode.getKey());
+ }
+ else
+ {
+ System.err
+ .println("Inconsistency in the IUBMB ambiguity code nomenclature table: collision for "
+ + acode.getKey() + " in residue " + r);
+ }
+ }
+ }
+ // and programmatically add in the ambiguity codes that yield the same amino
+ // acid
+ String[] unambcodons = codonHash2.keySet().toArray(new String[codonHash2.size()]);
+ for (String codon : unambcodons)
+ {
+ String residue = codonHash2.get(codon);
+ String acodon[][] = new String[codon.length()][];
+ for (int i = 0, iSize = codon.length(); i < iSize; i++)
+ {
+ String _ac = "" + codon.charAt(i);
+ List<String> acodes = _ambiguityCodes.get(_ac);
+ if (acodes != null)
+ {
+ acodon[i] = acodes.toArray(new String[acodes.size()]);
+ }
+ else
+ {
+ acodon[i] = new String[]
+ {};
+ }
+ }
+ // enumerate all combinations and test for veracity of translation
+ int tpos[] = new int[codon.length()], cpos[] = new int[codon.length()];
+ for (int i = 0; i < tpos.length; i++)
+ {
+ tpos[i] = -1;
+ }
+ tpos[acodon.length - 1] = 0;
+ int ipos, j;
+ while (tpos[0] < acodon[0].length)
+ {
+ // make all codons for this combination
+ char allres[][] = new char[tpos.length][];
+ String _acodon = "";
+ char _anuc;
+ for (ipos = 0; ipos < tpos.length; ipos++)
+ {
+ if (acodon[ipos].length==0 || tpos[ipos] < 0)
+ {
+ _acodon += codon.charAt(ipos);
+ allres[ipos] = new char[]
+ { codon.charAt(ipos) };
+ }
+ else
+ {
+ _acodon += acodon[ipos][tpos[ipos]];
+ String[] altbase = ambiguityCodes.get(acodon[ipos][tpos[ipos]]);
+ allres[ipos] = new char[altbase.length];
+ j = 0;
+ for (String ab : altbase)
+ {
+ allres[ipos][j++] = ab.charAt(0);
+ }
+ }
+ }
+ // test all codons for this combination
+ for (ipos = 0; ipos < cpos.length; ipos++)
+ {
+ cpos[ipos] = 0;
+ }
+ boolean valid = true;
+ do
+ {
+ String _codon = "";
+ for (j = 0; j < cpos.length; j++)
+ {
+ _codon += allres[j][cpos[j]];
+ }
+ String tr = codonHash2.get(_codon);
+ if (valid = (tr!=null && tr.equals(residue)))
+ {
+ // advance to next combination
+ ipos = acodon.length - 1;
+ while (++cpos[ipos] >= allres[ipos].length && ipos > 0)
+ {
+ cpos[ipos] = 0;
+ ipos--;
+ }
+ }
+ } while (valid && cpos[0] < allres[0].length);
+ if (valid)
+ {
+ // Add this to the set of codons we will translate
+// System.out.println("Adding ambiguity codon: " + _acodon + " for "
+// + residue);
+ codonHash2.put(_acodon, residue);
+ }
+ else
+ {
+// System.err.println("Rejecting ambiguity codon: " + _acodon
+// + " for " + residue);
+ }
+ // next combination
+ ipos = acodon.length - 1;
+ while (++tpos[ipos] >= acodon[ipos].length && ipos > 0)
+ {
+ tpos[ipos] = -1;
+ ipos--;
+ }
+ }
+ }
+
}
static
git://source.jalview.org / jalview.git / commitdiff