Researchers at Rice University found that CRISPR-induced double-strand breaks in the DNA caused numerous large unintended on-target genetic damages, including large and small deletions and insertions and chromosomal rearrangements of genetic material.
The latest in a long series of papers has been published, detailing the unintended effects of CRISPR gene editing. The new review summarises the many types of serious unintended on-target (at the intended edit site) DNA damage resulting from CRISPR/Cas gene editing.
The review appears as the European Commission and the U.K. government maintain their pretense that gene editing is a precise, predictable and controllable technique and that food plants made with this technology are therefore as safe as those produced by conventional breeding.
The authors of the new paper, from Rice University in the U.S., reviewed the literature on CRISPR gene editing in human, primate and mouse cells.
They found that CRISPR-induced double-strand breaks in the DNA caused numerous large unintended on-target genetic damages, including large and small deletions and insertions and chromosomal rearrangements of genetic material.
And they note that even large on-target gene modifications are not detectable by standard methods.
Because the unintended effects of CRISPR gene editing highlighted in the new review are on-target mutations at the intended edit site, improving the targeting of the editing tool isn’t going to solve these problems, as GMWatch has warned before.
CRISPR’s ‘potentially irreversible safety risks’
As we’ve come to expect, the authors of the new review are from the clinical gene therapy arena rather than the agricultural genetic engineering arena. As an example of the widespread concern about CRISPR’s imprecision in the clinical arena, a recent article in Forbes warns that gene editing “comes with potentially irreversible safety risks.”
This lie of omission leads to the grotesque and ironic situation where conflicted scientists and misguided politicians parrot sales pitches about precision and predictability, even as the scientific evidence of the opposite mounts up.
Inadequate screening for unintended effects
The authors of the new paper draw attention to the inadequate methods that many genetically modified organism (GMO) developers use to look for unintended effects of gene editing.
While they state that on-target large gene modifications can occur at high frequencies, they point out that they are “undetectable by standard short-range PCR [polymerase chain reaction]-based assays, leading to data misinterpretation, reduced efficacy, and potential safety concerns in therapeutic gene editing.”
GMWatch has repeatedly drawn attention to the biased and inadequate screening methods generally used by genetic engineers in the agricultural arena, which means they will miss many unintended effects.