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Two groups of researchers are questioning the results of an endeavor reported last year in which scientists edited the genomes of human embryos using CRISPR-Cas9. One team describes in Nature today (August 8) that when a similar method is applied to mouse embryos, their genomes end up with long deletions. The other critique lays out possible alternative explanations for the findings of the original study, specifically, the molecular mechanism by which the DNA is repaired after the nuclease cuts it.
The original authors used these challenges to apply extra scrutiny to their approach, and report in the same issue of Nature today that their results stand. “The additional retesting of the samples confirmed our original conclusion that this repair occurred as we described,” Shoukhrat Mitalipov, director of the Center for Embryonic Cell and Gene Therapy at Oregan Health and Sciences University and a leader of last ...
