Genes are the DNA based blueprint of the human body. Our genes provide the information cells use to grow and function. In some cases the cellular expression of aberrant proteins is caused by corrupted or missing genes, or by faulty modifications to the downstream products of genes. Traditional pharmaceutical-based treatments typically modify components of the cell or its environment to induce a therapeutic response. Gene therapy, however, is focused on utilizing viral-based technologies that deliver therapeutic genes to human cells or tissues to correct the genetic defect directly. These viral based technologies, known as vectors, have naturally evolved capabilities to deliver therapeutic genetic material to living cells.