Book Review: Lifespan

Link:https://astralcodexten.substack.com/p/book-review-lifespan

Graphic:

Excerpt:

David Sinclair – Harvard professor, celebrity biologist, and author of Lifespan – thinks solving aging will be easy. “Aging is going to be remarkably easy to tackle. Easier than cancer” are his exact words, which is maybe less encouraging than he thinks.

There are lots of ways that solving aging could be hard. What if humans worked like cars? To restore an old car, you need to fiddle with hundreds of little parts, individually fixing everything from engine parts to chipping paint. Fixing humans to such a standard would be way beyond current technology.

Or what if the DNA damage theory of aging was true? This says that as cells divide (or experience normal wear and tear) they don’t copy their DNA exactly correctly. As you grow older, more and more errors creep in, and your cells become worse and worse at their jobs. If this were true, there’s not much to do either: you’d have to correct the DNA in every cell in the body (using what template? even if you’d saved a copy of your DNA from childhood, how do you get it into all 30 trillion cells?) This is another nonstarter.

Sinclair’s own theory offers a simpler option. He starts with a puzzling observation: babies are very young [citation needed]. If a 70 year old man marries a 40 year old woman and has a baby, that baby will start off at zero years old, just like everyone else. Even more interesting, if you clone a 70 year old man, the clone start at zero years old.

….

So Sinclair thinks aging is epigenetic damage. As time goes on, cells lose or garble the epigenetic markers telling them what cells to be. Kidney cells go from definitely-kidney-cells to mostly kidney cells but also a little lung cell and maybe some heart cell in there too. It’s hard to run a kidney off of cells that aren’t entirely sure whether they’re supposed to be kidney cells or something else, and so your kidneys (and all your other organs) break down as you age. He doesn’t come out and say this is literally 100% of aging. But everyone else thinks aging is probably a combination of many complicated processes, and I think Sinclair thinks it’s mostly epigenetic damage and then a few other odds and ends that matter much less.

Author(s): Scott Alexander

Publication Date: 1 Dec 2021

Publication Site: Astral Codex Ten

A Primer on Insurance Policies and Genetics

Link: https://www.soa.org/resources/research-reports/2021/primer-ins-policies-genetics/

Full report: https://www.soa.org/globalassets/assets/files/resources/research-report/2021/primer-ins-policies-genetics-report.pdf

Graphic:

Excerpt:

A new subset of Somatic non-blueprint information is the growing field of Epigenetics, defined as changes ‘above
the genetics,’ where it has recently been found that lifestyle choices also induce non-heritable physical or chemical
changes directly on a person’s DNA after birth, and can be measured by isolating the DNA and revealing these
features. The U.S. Center for Disease Control states: “Epigenetics is the study of how your behaviors and
environment can cause changes that affect the way your genes work. Unlike genetic changes, epigenetic changes
are reversible and do not change your DNA sequence.” (9)


An example of the latter is a finding that the tips of our chromosomes – called telomeres – can shorten or lengthen
in correlation with health status and ‘biological aging,’ a finding that was the subject of a 2009 Nobel Prize (10). An
additional example of epigenetics is in tobacco use, shown below, and generally discussed at the 2020 SOA Health
Conference by Dr. Brian Chen at this link https://webcasts.soa.org/products/actuarial-innovation-and-technologyupdate-on-recent-research#tab-product_tab_speaker_s.

Author(s): James Timmins

Publication Date: March 2021

Publication Site: Society of Actuaries