Fig. 1: Human 8-cell embryos mediate robust mitochondrial base editing with DdCBE.

a Experimental workflow of DdCBE injection in human embryos and genotyping analysis. b Percentage of total sequencing reads with C·G base pair converted to T·A in ND4-DdCBE-injected 1-cell, 2-cell, 4-cell, and 8-cell embryos of 3PN. c Experimental workflow of DdCBE injection for off-target profiling in human 2PN embryos. d On-target efficiency of ND4-DdCBE in human 2PN embryos. Embryos injected with ND4-Dead-DdCBE + GFP or only GFP mRNA showed no base editing on the ND4 site. e Mitochondrial genome-wide off-target loci identified from human 2PN embryos injected with ND4-DdCBE. No SNV was identified in control embryos injected with ND4-Dead-DdCBE + GFP or GFP mRNA only whereas several SNVs were identified in embryos injected with both GFP and ND4-DdCBE mRNA, possibly due to off-target editing. f Sequence logos generated from sequences with off-target C·G to T·A conversions by ND4-DdCBE on mitochondrial DNA genome. Bits reflect sequence conservation at a given position. g Normal morphology of human 2PN embryos injected with ND4-DdCBE at different developmental stages. h Comparable developmental rate between uninjected human 2PN embryos and the ones injected with ND4-DdCBE. Data are presented as means ± SEM. P values were evaluated with the unpaired student’s t-test (two-tailed).