Researchers are finding ever more powerful ways to use the genome editing tool CRISPR. In the latest, a UK group used the technology to remove a critical gene needed for human development in order to learn more about the earliest steps of how embryos form. In a paper published in the journal Nature, Kathy Niakan, group leader from the Francis Crick Institute, and her colleagues snipped out one gene from the genome of a one-celled, just-fertilized human egg.