Only a hundred and fifty years have passed since Gregor Mendel’s discovery of simple Mendelian inheritance. In a remarkably short amount of time humans have achieved such impressive feats as sequencing the entire human genome and gaining understanding of the causes of most genetic disease. Now that researchers have all this information at hand, the focus has shifted to the design of reagents that can target specific genomic sequences. The rapid advancement of genome-editing techniques holds much promise for the field of human gene therapy. From bacteria to model organisms and human cells, genome editing tools such as zinc-finger nucleases (ZNFs), TALENs, and CRISPR/Cas...