Can someone explain why somatic mutations accumulate?
Recent study that hypothesized the theoretical limit on human lifespan due to accumulation of somatic mutations, especially in non-mitotic cells (e.g. heart and brain). https://www.nature.com/articles/s41514-026-00421-6
Why would repair mechanisms fail continually in a way that allows them to accumulate? I understand proofreading enzymes are imperfect, but this isn't like mitosis where if you miss it welp too bad the mutation is permanent now. Presumably in non-mitotic cells they have proofreading enzymes going up and down the entire DNA strand repeatedly forever (as long as the cell continues to live)? Why would they keep missing errors despite checking multiple times AND letting them accumulate? #science