throw new UnsupportedOperationException(errorMessage);
}
final IndexedIdentifier identifiers = reader.getTargetIdentifiers();
// add MT as a synonym for M:
identifiers.put(new MutableString("M"), identifiers.getInt(new MutableString("MT")));
targetIdentifiers = new DoubleIndexedIdentifier(identifiers);
isIndexed = reader.isIndexed();
// reader.close();
// reader = null;
targetSequenceNames = new ArrayList();