How and when organisms edit their own genomes

[Dan_Eastwood]

How and when organisms edit their own genomes
(Nature Genetics 2025)

The purpose of this Review is to provide an accessible overview of endogenous genome editing while offering insights and synthesis that will be of interest to domain experts. Although we acknowledge that the breadth of this topic has forced us to make occasional generalizations and omissions, our goal is not to obscure differences but instead to highlight similarities between editing systems even in very distantly related taxa. As the title of this work suggests, we will focus on the genetic mechanisms of editing (‘how’), with particular reference to DNA repair (Box 1), and also on the functional circumstances in which the editing occurs (‘when’). As a conceptual framework, we group editing systems into three categories (deletions, insertions and substitution), and we will demonstrate that the editing systems within each category often enlist similar editing mechanisms despite superficially dissimilar results.

https://www.nature.com/articles/s41588-025-02230-1

I thought it might be a good idea to post this for discussion before the other guys get a chance to mangle it. Pretty sure this is paywalled, but I have access, if needed.

[Mark_Sturtevant]

I had learned long ago about the strange phenomenon of what is called “chromatin diminution”, where sometimes extensive parts of the genome are discarded in the somatic cell line. This occurs in a range of species, including ciliate protozoa (where it happens in the non-germ line nucleus), and in various invertebrates and vertebrates. Here is Wikipedia on it: Somatic genome processing - Wikipedia I did not see anything about why or how, which is possibly bc I did not look hard enough, or bc it has not been really looked at yet.
It’s possible that the mechanism in which parts of a genome are spliced away in chromatin diminution is similar to the other genome editing mechanisms. It would be cool if these seemingly disparate instances are similar. Why not convergent evolution at the genetic level?