My molecular biologist friend's comment on this is pretty on-point, so I though it was worth sharing: This is one of the first gene therapy studies I've seen t

My molecular biologist friend's comment on this is pretty on-point, so I though it was worth sharing: This is one of the first gene therapy studies I've seen that didn't end with "but we accidentally gave our subjects aggressive leukemias, whoops". Extending telomeres is interesting! And there's a lot of good data that critically short telomeres can lead to and cause cellular senescence and death. But telomeres are just end-caps of entire chromosomes worth of DNA. They are interesting with regards to aging partly just because they are measurable and quantifiable, but aging is so much more complicated and multifactorial than just telomere length, that manipulating telomere length and saying this solves aging is an overstatement. Cancers can express telomerase and immortalize themselves just fine, for example. Manipulating telomeres to investigate aging reminds me of this classic joke. A cop pulls up late at night to a biologist slowly walking a spiral around a streetlight, staring at the ground intently. "Uh, sir," says the cop, "what are you doing?" "Looking for my keys," replies the biologist. "I dropped them somewhere on this street. "I see," says the cop. "But why are you just looking around this light?" "Light's better here", he replies.