[nonbel]

I quickly looked through your links. The first article you link seems to lack any control group (which we need to assess the proportion of pre-existing mutant cells), the second is primary research but does not mention CRISPR-Cas9, and the other two are review articles that don't contain any quantitative data.

As mentioned, I only looked quickly, but I do not think any will be helpful on the point I am bringing up. Let me know if I missed it.

[AlexCoventry]

If you want to know why people are assuming NHEJ occurs at a double-stranded break, you might look at the dozen or so references in the first paragraph of https://www.ncbi.nlm.nih.gov/pmc/articles/PMC231204/pdf/1621...

[nonbel]

Frequency of survival is shown in table 2... it ranges from 5/1,000 to 1/100,000. So cell death is a 200-100,000 times more common result than NHEJ using those methods. I have no idea how well that would correspond to the conditions we are interested here, but see no way this paper can be taken to support NHEJ is a more likely result than cell death.

It also says: "Yeasts, like other eucaryotes, exhibit cell cycle arrest in response to DNA damage (17)."