Scientists Successfully Edited DNA in Human Embryos in Lab Study
Researchers at Columbia University say they have achieved precise gene editing in very early human embryos, a result that pushes embryonic DNA repair from theory into the lab. The study has not yet been published in a peer-reviewed journal, and was posted online as a preliminary paper. The embryos were used only for research, not for implantation or fertility treatment.
Prof. Lina Bassel Salomon, head of national innovation and research in genomic medicine at Maccabi Healthcare Services, said CRISPR opened the door to targeted DNA repair, but early versions often cut both strands of DNA and caused errors, including chromosome damage. The newer method, called Base Editing, changes a single genetic letter without cutting out large sections. It trims only one DNA strand, which sharply reduces mistakes, and the new study tested whether that approach is safer in embryos and can correct disease-causing mutations with less harm.
The researchers focused on the PCSK9 gene, linked to high cholesterol and cardiovascular risk, and the HBG1/2 genes, tied to fetal hemoglobin and potential treatment of blood diseases such as sickle cell anemia. They reported relatively efficient editing, without the kinds of damage seen in earlier embryo experiments. They also found that when the editing system was delivered as protein, embryos developed to the blastocyst stage, but when it was delivered as RNA, development stopped early.
A major unresolved problem is mosaicism, meaning not every cell in the embryo is edited. Bassel Salomon said the results were not perfect, because different embryos showed different correction rates and no case reached 100% repair, but the lower damage still makes the work important. She stressed that clinical use remains far away, and that in most countries genetic changes in embryos before implantation are illegal, citing the 2018 China case involving He Jiankui, who was imprisoned after announcing genetically edited babies. For now, the study matters mainly as a proof of concept and a possible tool for future disease research, not for designing babies.
