code: public GeneSequence addGene(AccessionID accession, int bioBegin, int bioEnd, Strand strand) {
  		GeneSequence geneSequence = new GeneSequence(this, bioBegin, bioEnd, strand);
  		geneSequence.setAccession(accession);
  		geneSequenceHashMap.put(accession.toString(), geneSequence);
  		return geneSequence;
  	}
docs: Add a gene to the chromosome sequence using bioIndexing starts at 1 instead of 0. The
  GeneSequence that is returned will have a reference to parent chromosome sequence
  which actually contains the sequence data. Strand is important for positive and negative
  direction where negative strand means we need reverse complement. If negative strand then
  bioBegin will be greater than bioEnd
  
  
  @param accession
  @param begin
  @param end
  @param strand
  @return