+10 if I could. Especially since the article notes that such mutations can be caused by "exposure to excess ultraviolet radiation". AKA sunburn?

There is a difference in where the mutations occur in the body. Sunburn still primarily causes mutation in and near the skin. radiation can cause mutations in the organs deeper in the body which are less robust against radiation, for the exact reason that the skin is usually a sufficient barrier.

I mean, yes, sunburn is excess ultraviolet radiation, but there are lots of other (more severe) forms and it’s pretty straightforward to understand they mean “excess [beyond the type experienced in the comparison populations, namely, the general population, who tend to experience minor exposure to excessive ultraviolet radiation, aka sunburn].”

This isn’t the “gotcha” you think it is.

And how can we rule out that the mutations are not introduced in time at rest? All these blood samples are more than 20 years old.

Mutations are caused by errors in DNA repair mechanisms. Radioactive particles smash into DNA, breaking the bonds that hold it together. You have a whole system for DNA repair in your cells, but it's not 100% accurate, and so the more times you have to repair things, the more errors you're going to see.

And the reason you'll never see it in random frozen samples from 20 years ago is that your cells have to be alive for it to happen, and those ones aren't.

Thing is, if your freze something, that does not stop its internal decay due to radiation, e.g. carbon 14, kalcium etc, its just that the errors which occur arent multipled and the relatively short time is insufficient. But freeze a corpse for a millenia and it will turn into swiss cheese from self radiation, even if it was healthy when you froze it.

Well you are right when you consider that a "mutation" can just be caused by the DNA copy/repair mechanisms. But what if a chemical degradation could also cause it? Perhaps a sample dna lost bases and the sequencing read the resulting base sequence as a new mutated sequence? I am just being skeptical.

The samples were stored at -80°C, where any chemical degradation process would be slowed down immensely if not come to a virtual halt.

Maybe the scientists manufactured the data with CRISPR. /s

In seriousness, we can come up with lots of out-there scenarios. But this finding is intrinsically interesting enough to warrant discussion, critique, and further analysis.

Your critiques aren’t a failure of the system, or a “dunk” on the scientific establishment. This open, democratic dialogue is _the entire point of the scientific publication process._

I am actually not critical of the deductions.I never even considered bad intentions.

Being skeptical is required to get to reality. Do we really know if the storage procedures/ thawing procedures can't have a side effect of mutations on the samples? We are still learning too much about the epigenetics and we already know low temperatures can have adverse effects on tissues. So I just voiced my idea on this.

See the twin study, as mentioned by someone else.