+ * Computes non-synonymous peptide variants from codon variants and adds them
+ * as sequence_variant features on the protein sequence (one feature per
+ * allele variant). Selected attributes (variant id, clinical significance)
+ * are copied over to the new features.
+ *
+ * @param peptide
+ * the protein sequence
+ * @param peptidePos
+ * the position to compute peptide variants for
+ * @param codonVariants
+ * a list of dna variants per codon position
+ * @return the number of features added
+ */
+ static int computePeptideVariants(SequenceI peptide, int peptidePos,
+ List<DnaVariant>[] codonVariants)
+ {
+ String residue = String.valueOf(peptide.getCharAt(peptidePos - 1));
+ int count = 0;
+ String base1 = codonVariants[0].get(0).base;
+ String base2 = codonVariants[1].get(0).base;
+ String base3 = codonVariants[2].get(0).base;
+
+ /*
+ * variants in first codon base
+ */
+ for (DnaVariant var : codonVariants[0])
+ {
+ if (var.variant != null)
+ {
+ String alleles = (String) var.variant.getValue("alleles");
+ if (alleles != null)
+ {
+ for (String base : alleles.split(","))
+ {
+ String codon = base + base2 + base3;
+ if (addPeptideVariant(peptide, peptidePos, residue, var, codon))
+ {
+ count++;
+ }
+ }
+ }
+ }
+ }
+
+ /*
+ * variants in second codon base
+ */
+ for (DnaVariant var : codonVariants[1])
+ {
+ if (var.variant != null)
+ {
+ String alleles = (String) var.variant.getValue("alleles");
+ if (alleles != null)
+ {
+ for (String base : alleles.split(","))
+ {
+ String codon = base1 + base + base3;
+ if (addPeptideVariant(peptide, peptidePos, residue, var, codon))
+ {
+ count++;
+ }
+ }
+ }
+ }
+ }
+
+ /*
+ * variants in third codon base
+ */
+ for (DnaVariant var : codonVariants[2])
+ {
+ if (var.variant != null)
+ {
+ String alleles = (String) var.variant.getValue("alleles");
+ if (alleles != null)
+ {
+ for (String base : alleles.split(","))
+ {
+ String codon = base1 + base2 + base;
+ if (addPeptideVariant(peptide, peptidePos, residue, var, codon))
+ {
+ count++;
+ }
+ }
+ }
+ }
+ }
+
+ return count;
+ }
+
+ /**
+ * Helper method that adds a peptide variant feature, provided the given codon
+ * translates to a value different to the current residue (is a non-synonymous
+ * variant). ID and clinical_significance attributes of the dna variant (if
+ * present) are copied to the new feature.
+ *
+ * @param peptide
+ * @param peptidePos
+ * @param residue
+ * @param var
+ * @param codon
+ * @return true if a feature was added, else false
+ */
+ static boolean addPeptideVariant(SequenceI peptide, int peptidePos,
+ String residue, DnaVariant var, String codon)
+ {
+ /*
+ * get peptide translation of codon e.g. GAT -> D
+ * note that variants which are not single alleles,
+ * e.g. multibase variants or HGMD_MUTATION etc
+ * are currently ignored here
+ */
+ String trans = codon.contains("-") ? "-"
+ : (codon.length() > CODON_LENGTH ? null : ResidueProperties
+ .codonTranslate(codon));
+ if (trans != null && !trans.equals(residue))
+ {
+ String residue3Char = StringUtils
+ .toSentenceCase(ResidueProperties.aa2Triplet.get(residue));
+ String trans3Char = StringUtils
+ .toSentenceCase(ResidueProperties.aa2Triplet.get(trans));
+ String desc = "p." + residue3Char + peptidePos + trans3Char;
+ // set score to 0f so 'graduated colour' option is offered! JAL-2060
+ SequenceFeature sf = new SequenceFeature(
+ SequenceOntologyI.SEQUENCE_VARIANT, desc, peptidePos,
+ peptidePos, 0f, var.getSource());
+ StringBuilder attributes = new StringBuilder(32);
+ String id = (String) var.variant.getValue(ID);
+ if (id != null)
+ {
+ if (id.startsWith(SEQUENCE_VARIANT))
+ {
+ id = id.substring(SEQUENCE_VARIANT.length());
+ }
+ sf.setValue(ID, id);
+ attributes.append(ID).append("=").append(id);
+ // TODO handle other species variants JAL-2064
+ StringBuilder link = new StringBuilder(32);
+ try
+ {
+ link.append(desc)
+ .append(" ")
+ .append(id)
+ .append("|http://www.ensembl.org/Homo_sapiens/Variation/Summary?v=")
+ .append(URLEncoder.encode(id, "UTF-8"));
+ sf.addLink(link.toString());
+ } catch (UnsupportedEncodingException e)
+ {
+ // as if
+ }
+ }
+ String clinSig = (String) var.variant.getValue(CLINICAL_SIGNIFICANCE);
+ if (clinSig != null)
+ {
+ sf.setValue(CLINICAL_SIGNIFICANCE, clinSig);
+ attributes.append(";").append(CLINICAL_SIGNIFICANCE).append("=")
+ .append(clinSig);
+ }
+ peptide.addSequenceFeature(sf);
+ if (attributes.length() > 0)
+ {
+ sf.setAttributes(attributes.toString());
+ }
+ return true;
+ }
+ return false;
+ }
+
+ /**
+ * Builds a map whose key is position in the protein sequence, and value is a
+ * list of the base and all variants for each corresponding codon position