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Comment by reliablereason | Hacker News Reader

How come almost all humans live longer than dogs then. Dogs don't smoke and they are very physically active, yet they generally die before the age of 20*.

The article is a based on a over generalisation from study results that are not applicable in the way that the article claims.

*The dog metaphor is sort of a joke, but it is true for the human case to, due to the fact that you cant factor out the genetic "effect" on behaviour.... ie. behaviour and genes are too intertwined to separate from each other. Smokers smoke in part cause they have the genes that make them more likely to smoke (or exercise, or overeat, or do whatever; just pick any example that is unhealthy).

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Dog aging is irrelevant. It's well-documented that dogs have a faster biological aging process due at least in part to the telomere caps on chromosomes which protect the DNA. Dogs lose these caps at a rate around ten times the human rate.

https://www.sciencedirect.com/science/article/pii/S221112471...

I remember seeing discourse recently saying telomere shortening is a side effect more than a cause of aging as a function and happens as a function of DNA damage. Important to consider

Sure, but it also has some correlation to body size. Larger animals generally live longer.

Then why do large-breed dogs die around 8 years of age when small-breed dogs can live to twice that easy?

I think it's fair to assume that we're not talking about the genetics of other species here.

Genetics does not draw neat lines.

In the same way that there is not a neat line where land meets sea, yet any reasonable person can distinguish the difference between the two and understand that they are not the same.

It's pretty obvious that it only applies to the same specie. If you live 100m from a highway, breath brake pad and tire particules all day, smoke 2 packs of cigs a day and drink 1L of vodka every morning you will statistically live a shorter life than your genetic twin who lives in an unpolluted rural area who eat pesticide free food and don't smoke/drink

That's all there is to it, some people smoke and live long, some people don't smoke and die young, but statistically no one smokes a lot and live longer as a result.

Just look at the leading causes of mortality, they're mostly behavior or environment related

I'd think of it in terms of a sort of species normative lifespan and indicators of aging. Let's say it's 80 effective years. What this study is saying that factors other than genes have much more more influence on whether you make it to (or even past) the normative lifespan/age. Not that the length of the generalized normative lifespan isn't a product of genes, or that individuals who appear as severe outliers aren't doing so because of genetic factors. But that the largest factor impacting premature expression of normative age or pre-normal-age death aren't genetically driven at the population level.

I would note, however, that this result is going to be extremely influenced by the society being studied. If famine is widespread, then many genetic factors won't matter. Similar for war, etc. (And this is probably partially why socioeconomic factors have a big influence.)

The article is talking about genetic variation within humans. The title omits this, making it an incorrect summary of the article (and it’s unclear what it even means)

i understand "affected by genes" to mean exactly "genetic variation". what else could it mean?

People might expect “affected by genes” to be an objective fact not related to the current variation of genes we actually have. For example, let’s say there’s a gene that reduces lifespan by 1 year that half of people have. If this gene spread so that in the future everyone had the gene, lifespan would suddenly be “less affected by genes” than before. (Because variation in this gene no longer exists, genetic variation will have less effect on lifespan.) But of course, lifespan is still being affected by this gene.

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