private void insertDNA(int index, String str) {
		if (strands == null || strands[DNA_STRAND_BASE] == null || strands[DNA_STRAND_COMPL] == null)
			return;
		if (str == null || str.length() < 1)
			return;
		if (index < 0)
			index = 0;
		if (index > getLength())
			index = getLength();
		for (int i = 0; i < str.length(); i++) {
			char n = str.charAt(i);
			Nucleotide nuc = Nucleotide.getNucleotide(n);
			Nucleotide complNuc = nuc.getComplementaryNucleotide(false);
			strands[DNA_STRAND_BASE].addNucleotide(index, nuc);
			strands[DNA_STRAND_COMPL].addNucleotide(index, complNuc);
			index++;
		}
	}