Heidi Ledford, Nature News, 20 September 2017, http://www.nature.com/news/crispr-used-to-peer-into-human-embryos-first-days-1.22646
Developmental biologists in the United Kingdom have identified differences in the OCT4 gene between mouse and human embryos by using CRISPR/Cas9 to disrupt OCT4. While disruption of OCT4 results in abnormal embryo development in both mice and human embryos, human embryos lacking the protein quit developing earlier than mouse embryos and showed a completely different pattern of gene expression. Additionally, the OCT4 human embryo mutant showed abnormalities in cells that give rise to the placenta. The researchers hope their work can be sued to improve IVF treatments and explain why some pregnancies fail.