Researchers identify NANOG gene role in human embryo formation

Researchers have identified the NANOG gene as the trigger that initiates the developmental program resulting in cells forming a human body. The team reached this conclusion by applying CRISPR base editing to disable the gene in fertilized human eggs donated by women undergoing IVF treatments.

When NANOG was disabled, none of the resulting cells developed into those that form the embryo itself. Embryos still appeared normal under a microscope, and current IVF selection relies largely on visual shape assessment.

Differences from animal studies Animal studies had shown NANOG plays a role in embryonic development, but the human results differed from those in mice. Disabling the gene in mouse eggs prevented formation of yolk sac progenitors, whereas the same change in human eggs blocked formation of embryo-forming cells.

The study also compared base editing with earlier CRISPR methods. Base editing changes a single DNA letter at a time, which the researchers said reduces the likelihood of unintended chromosomal abnormalities.

Limitations and next steps Mosaicism remained an issue, with half the edited human eggs still containing a mix of edited and unedited cells. The team stated that this rate would be too high for attempts to correct disease-causing mutations. Kathy Niakan at the University of Cambridge said a better understanding of these early stages could improve stem cell research and regenerative medicine.

The work was published in Nature with the DOI 10.1038/s41586-026-10792-1.