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Comment by wturner | Hacker News Reader

The older I get the more I realize our biology has an agenda of its own. I wonder if people who smoke cigarettes are really unconsciously building up their immune systems for their great great great grand children for an unforeseen future where the atmosphere gets really bad and they need the immunity to live long lives.

These kinds of thoughts make for great sci-fi.

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You know Lamarkism was discredited long ago?

Anyway I do believe a good story could come from there.

Lamarkism might be seeing a revival. Not really! But something you might see as similar: epigenetics. Scientists are increasingly aware that gene expression is controlled by more than the genes themselves. Some of these control factors may be inheritable.

[citation needed] It's important to be clear what people are talking about when they mention epigenetics. What examples did you have in mind?

He gave you a citation. search on epigenetics. It's seen a lot of headlines in the last couple years.

Where do we see a specific citation in the thread below my question or nearby? A lot of different phenomena have been labeled "epigenetic" in the last few years, without great consistency. I have quite a large number of reference works on genetics at hand in my office, and I was asking specifically which study the HN participant to whom I was replying had in mind.

That's just biology evolving your brain in such a way that you are hardwired to discredit Lamarkism lest you start interfering with the great plan.

But could this work with a non-Lamarkian explanation: say most people would smoke, some of them have a random mutation which makes them resistant to it, so they would be more likely to have children and care for them, so the trait would become more common in next generation. Isn't it just darwinian adaptation then?

Except people rarely die before breeding age from smoking (ever?), so no effect.

I guess in older times even dying long after breeding could have had an effect: not being able to look after children => less chance of survival of children carrying same gene.

You are right that in modern society this effect is not so powerful probably, but if we take this reasoning forward, it could mean that diseases of old age will be more and more prevalent as there is no selection pressure for defense against them. Is this happening already?

> Except people rarely die before breeding age from smoking (ever?), so no effect.

Grandparents provide some survival and family size benefits.

with the stigma placed on smoking in many societies smoking could in fact inhibit ones ability to breed (or at least influence it).

Except that the heaviest smokers are often found in the lower classes who also breed more than their rich and middle class comrades.

Epigenetics is the modern incarnation of Lamarkism. While epigenetics doesn't affect the underlying genetic code, some forms of it modify the expression patterns of genes (look up heritability of methylation patterns) which often have an environmentally determined component.

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