An artist's rendition of genome engineering using enzymes from the microbial CRISPR/Cas immune system. The Cas9 nuclease can be recruited to distinct locations on the genome by RNA "guides" to introduce breaks in the genome and facilitate editing of the DNA sequence. The CRISPR-based genome engineering technology is efficient and simple to use and may find broad applications in both research and medicine. This image relates to a paper that appeared in Jan. 3, 2013, issue of Science Express, published by AAAS. The paper, by Le Cong at Broad Institute of MIT and Harvard in Cambridge, Mass., and colleagues was titled, "Multiplex Genome Engineering Using CRISPR/Cas Systems."