Off target effects from CRISPR is not new. The method leverages DNA repair mechanisms in the cell to do the recombination. All errors involved in those DNA repair mechanisms (there are distinct ones) would apply here。
Moreover - this is biology. Biology is messy. Mistakes are the reason why the system works (evolution). To say that off-target effects were unanticipated is nonsense. Rather - how many off target effects will there be, can they be predicted, and can their effect be predicted.
But if CRISPR cuts off a single DNA sequence, surely the repair mechanisms won't damage a random gene far away. My very limited understanding is this paper is reporting widely spread damage on the genome.
The original bacteria CRISPR can only cut off pre-defined sequences, but the artificial gene tech CRISPR can add and edit as well. I'm wondering if the later two modes are the sources of the genome damage.
> but the artificial gene tech CRISPR can add and edit as well.
I was under the impression that addition and editing capability were essentially done by injecting the sequence that is desired and performing the cut. Then you simply rely on the repair mechanisms to have a chance to put the new segment in instead of the old segment. Is that not the case?