throw new IllegalArgumentException("Invalid spacer position"); //$NON-NLS-1$
}
spacerPosition = spacerPos;
//Create and set up a spacer library
TagLibrary spacerLib = new SpacerLibrary(0, NucleotideSequence.DNA);
//parse the spacer string and check that its valid
spacerSequence = ""; //$NON-NLS-1$
for (int i = 0; i < spacerString.length(); i++) {
Nucleotide nt = NucleotideSequenceHandler.getNucleotide(spacerString.