private static Type typeOfBiallelicVariant(Allele ref, Allele allele) {
if (ref.isSymbolic())
throw new IllegalStateException(
"Unexpected error: encountered a record with a symbolic reference allele");
if (allele.isSymbolic()) return Type.SYMBOLIC;
if (ref.length() == allele.length()) {
if (allele.length() == 1) return Type.SNP;
else return Type.MNP;
}
// Important note: previously we were checking that one allele is the prefix of the other.
// However, that's not an
// appropriate check as can be seen from the following example:
// REF = CTTA and ALT = C,CT,CA
// This should be assigned the INDEL type but was being marked as a MIXED type because of the
// prefix check.
// In truth, it should be absolutely impossible to return a MIXED type from this method because
// it simply
// performs a pairwise comparison of a single alternate allele against the reference allele
// (whereas the MIXED type
// is reserved for cases of multiple alternate alleles of different types). Therefore, if we've
// reached this point
// in the code (so we're not a SNP, MNP, or symbolic allele), we absolutely must be an INDEL.
return Type.INDEL;
// old incorrect logic:
// if (oneIsPrefixOfOther(ref, allele))
// return Type.INDEL;
// else
// return Type.MIXED;
}
public boolean hasSymbolicAlleles() {
for (final Allele a : getAlleles()) {
if (a.isSymbolic()) {
return true;
}
}
return false;
}
public static VariantContext createVariantContextWithTrimmedAlleles(VariantContext inputVC) {
// see if we need to trim common reference base from all alleles
boolean trimVC;
// We need to trim common reference base from all alleles in all genotypes if a ref base is
// common to all alleles
Allele refAllele = inputVC.getReference();
if (!inputVC.isVariant()) trimVC = false;
else if (refAllele.isNull()) trimVC = false;
else {
trimVC =
(AbstractVCFCodec.computeForwardClipping(
new ArrayList<Allele>(inputVC.getAlternateAlleles()),
inputVC.getReference().getDisplayString())
> 0);
}
// nothing to do if we don't need to trim bases
if (trimVC) {
List<Allele> alleles = new ArrayList<Allele>();
GenotypesContext genotypes = GenotypesContext.create();
// set the reference base for indels in the attributes
Map<String, Object> attributes = new TreeMap<String, Object>(inputVC.getAttributes());
Map<Allele, Allele> originalToTrimmedAlleleMap = new HashMap<Allele, Allele>();
for (Allele a : inputVC.getAlleles()) {
if (a.isSymbolic()) {
alleles.add(a);
originalToTrimmedAlleleMap.put(a, a);
} else {
// get bases for current allele and create a new one with trimmed bases
byte[] newBases = Arrays.copyOfRange(a.getBases(), 1, a.length());
Allele trimmedAllele = Allele.create(newBases, a.isReference());
alleles.add(trimmedAllele);
originalToTrimmedAlleleMap.put(a, trimmedAllele);
}
}
// detect case where we're trimming bases but resulting vc doesn't have any null allele. In
// that case, we keep original representation
// example: mixed records such as {TA*,TGA,TG}
boolean hasNullAlleles = false;
for (Allele a : originalToTrimmedAlleleMap.values()) {
if (a.isNull()) hasNullAlleles = true;
if (a.isReference()) refAllele = a;
}
if (!hasNullAlleles) return inputVC;
// now we can recreate new genotypes with trimmed alleles
for (final Genotype genotype : inputVC.getGenotypes()) {
List<Allele> originalAlleles = genotype.getAlleles();
List<Allele> trimmedAlleles = new ArrayList<Allele>();
for (Allele a : originalAlleles) {
if (a.isCalled()) trimmedAlleles.add(originalToTrimmedAlleleMap.get(a));
else trimmedAlleles.add(Allele.NO_CALL);
}
genotypes.add(Genotype.modifyAlleles(genotype, trimmedAlleles));
}
final VariantContextBuilder builder = new VariantContextBuilder(inputVC);
return builder
.alleles(alleles)
.genotypes(genotypes)
.attributes(attributes)
.referenceBaseForIndel(new Byte(inputVC.getReference().getBases()[0]))
.make();
}
return inputVC;
}
public static VariantContext createVariantContextWithPaddedAlleles(
VariantContext inputVC, boolean refBaseShouldBeAppliedToEndOfAlleles) {
// see if we need to pad common reference base from all alleles
boolean padVC;
// We need to pad a VC with a common base if the length of the reference allele is less than the
// length of the VariantContext.
// This happens because the position of e.g. an indel is always one before the actual event (as
// per VCF convention).
long locLength = (inputVC.getEnd() - inputVC.getStart()) + 1;
if (inputVC.hasSymbolicAlleles()) padVC = true;
else if (inputVC.getReference().length() == locLength) padVC = false;
else if (inputVC.getReference().length() == locLength - 1) padVC = true;
else
throw new IllegalArgumentException(
"Badly formed variant context at location "
+ String.valueOf(inputVC.getStart())
+ " in contig "
+ inputVC.getChr()
+ ". Reference length must be at most one base shorter than location size");
// nothing to do if we don't need to pad bases
if (padVC) {
if (!inputVC.hasReferenceBaseForIndel())
throw new ReviewedStingException(
"Badly formed variant context at location "
+ inputVC.getChr()
+ ":"
+ inputVC.getStart()
+ "; no padded reference base is available.");
Byte refByte = inputVC.getReferenceBaseForIndel();
List<Allele> alleles = new ArrayList<Allele>();
for (Allele a : inputVC.getAlleles()) {
// get bases for current allele and create a new one with trimmed bases
if (a.isSymbolic()) {
alleles.add(a);
} else {
String newBases;
if (refBaseShouldBeAppliedToEndOfAlleles)
newBases = a.getBaseString() + new String(new byte[] {refByte});
else newBases = new String(new byte[] {refByte}) + a.getBaseString();
alleles.add(Allele.create(newBases, a.isReference()));
}
}
// now we can recreate new genotypes with trimmed alleles
GenotypesContext genotypes = GenotypesContext.create(inputVC.getNSamples());
for (final Genotype g : inputVC.getGenotypes()) {
List<Allele> inAlleles = g.getAlleles();
List<Allele> newGenotypeAlleles = new ArrayList<Allele>(g.getAlleles().size());
for (Allele a : inAlleles) {
if (a.isCalled()) {
if (a.isSymbolic()) {
newGenotypeAlleles.add(a);
} else {
String newBases;
if (refBaseShouldBeAppliedToEndOfAlleles)
newBases = a.getBaseString() + new String(new byte[] {refByte});
else newBases = new String(new byte[] {refByte}) + a.getBaseString();
newGenotypeAlleles.add(Allele.create(newBases, a.isReference()));
}
} else {
// add no-call allele
newGenotypeAlleles.add(Allele.NO_CALL);
}
}
genotypes.add(
new Genotype(
g.getSampleName(),
newGenotypeAlleles,
g.getLog10PError(),
g.getFilters(),
g.getAttributes(),
g.isPhased()));
}
return new VariantContextBuilder(inputVC).alleles(alleles).genotypes(genotypes).make();
} else return inputVC;
}