A Crack in Creation

Jennifer A. Doudna, PhD, and Samuel H. Sternberg, PhD, detail the history, ethical and safety issues, and likely applications of the gene-editing tool CRISPR, which enables scientists potentially to eliminate genes that cause cancer and other diseases, make food healthier, and even bring back extinct creatures like the woolly mammoth.

CRISPR

The CRISPR process, the authors explain, developed from research into an unusual DNA array found in bacterial cells. The array consisted of two types of alternating DNA sequences. One type, termed “repeats,” always contained an identical set of about 30 letters of DNA. These repeats were palindromic; their letters read the same forward and backward. Between each repeat was another DNA set, the interspace.