Molecular characterization of human targeted and control embryos. (a) Immunofluorescence analysis of TEAD4-targeted and control embryos for TEAD4 (red), CDX2 (green), SOX2 (yellow) and DAPI (blue). (b) Immunofluorescence analysis of TEAD4-targeted and control embryos for TEAD4 (red), CDX2 (green), GATA3 (purple) and DAPI (blue). DNA was extracted from the immunostained blastocysts and was subjected to NGS. The exact editing efficiencies and mutational signatures can be found in Supplementary Table SVII—embryos 23, 24 and 25 as they are presented from top to bottom in Fig. 4b. TEAD4,transcriptional-enhanced associate domain family member 4; CDX2, caudal-type homeobox protein 2; SOX2, SRY-box transcription factor; GATA3, GATA-binding protein 3; NGS, next generation sequencing; DAPI, 4',6'-diamidino-2-phenylindole.