code: public int geneCount() {
  		int count = 0;
  		for (int i = 0, n = _chromosomes.length(); i < n; ++i) {
  			count += _chromosomes.get(i).length();
  		}
  		return count;
  	}
docs: Return the number of genes this genotype consists of. This is the sum of
  the number of genes of the genotype chromosomes.
  
  @return Return the number of genes this genotype consists of.