[philgoetz]

Probably. On the other hand, cells which have a shorter lifespan might have more mutations, since some mutations are introduced during replication--several per genome per replication, I think? On the other other hand, if they're produced from stem cells, that would keep the mutations down.

It probably also is related to the fact that neurons use a lot of energy and have a lot of mitochondria. Energy requires oxidative phosphorylation in the mitochondria, which produces a lot of free radicals, which damage DNA.

Yet, 1700 (the number they reported is 1700, not 1000) is about typical. Many cancer cells have been sequenced; typical findings are that about 100 genes in cancer cells have acquired mutations, about 10 of which contribute to the cancer. Genes comprise about 1% of DNA; this suggests that the typical somatic cell has 1000 to 10,000 acquired mutations. (1000 assuming that all 90 mutations past the 10 that caused the cancer happened after the tissue went cancerous; 10,000 assuming they all happened earlier. Though that linear interpolation is a bad estimate, because genes and intergenic DNA mutate at different rates, owing to transcription and chromatin.)

However, if they sequenced just the exome (the expressed genes) rather than the entire genome, then 1000 is 10x typical. I can't tell, since their paper is paywall-protected.