Controversial CRISPR-causes-unwanted-mutations study possibly tainted by use of closely-related mice

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In May 2017, a study claimed that the revolutionary CRISPR gene editing technique can cause thousands of unwanted and potentially dangerous mutations. The authors called for regulators to reassess the safety of the technique.

But doubts were raised about these claims from the very beginning, not least because it was a tiny study involving just three mice…Now a paper…has proposed a simple and more plausible explanation for the controversial results.

When Stephen Tsang of Columbia University Medical Center and colleagues compared the entire genomes of two CRISPR-edited mice with a third one, they found thousands of shared mutations in the two edited mice.

Tsang and co attributed to these mutations to CRISPR…Tsang and colleagues claimed that by sequencing the entire genome, they found off-target mutations missed by studies that only looked at sites resembling the target sequence. But there is a much simpler explanation, says the latest study: the two CRISPR-edited mice just happened to be more closely related and thus shared more mutations.

The shared mutations in the edited mice were nowhere near DNA sequences resembling the one were targeted for editing, [the researchers] point out, so it’s far from clear why CRISPR would cause mutations in these same sites in two different mice.

[Read the full study here (behind paywall)]

The GLP aggregated and excerpted this blog/article to reflect the diversity of news, opinion, and analysis. Read full, original post: CRISPR gene editing technique is probably safe, study confirms