Do catastrophic events have any affect on human populations?

Something like the recent Earthquake in China, or for a more extreme example the Black Death in Europe, kill off a large number of the population. Are such events selective enough about who lives and dies that they can alter the genetics of the population?

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"I worry that, especially as the Millennium edges nearer, pseudo-science and superstition will seem year by year more tempting, the siren song of unreason more sonorous and attractive." - Carl Sagan, 1995

It's thought that the prevalence of sickle cell and beta thalassemia genes in people from tropical or mediterranean climates is because carriers of those traits are more resistant to malaria. Is that the kind of thing you are looking for?

Nick

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Nick Theodorakis

Sickle cell anemia is a genetic response to malaria. Those with only one gene (carriers) are more resistant to malaria. The problem comes when a person inherits a gene from both parents, therefore being an active case of the disease. In essence, nature trades the lives of the few (sickle cell) for the lives of the many (malaria).

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T. Anderson

Maybe these events can select people with a tendency to live outside buildings...

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It's my understanding that truly catastrophic events have no predictable effect on human evolution because the event is pretty much nonselective (ex: earthquake strikes at night, survivors are determined by which buildings didn't collapse).

But, if the event is such that the local population is severely reduced (and then not immediately replenished by a larger group) , any uncommon traits that randomly survive can rapidly establish themselves in the remaining population if they offer selective reproductive success. Based on human genomic work, it is thought the modern human population passed through such a population bottleneck not all that long ago.

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If they can get you asking the wrong questions, they don't have to worry about the answers.

Whether or not you are killed in an earthquake is pretty much random. It's not related to your genotype. By contrast, whether or not you die in a malaria epidemic is highly correlated with your genotype.

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"A witty saying proves nothing" Voltaire.
"All your bias are belong to us" Ara Pacis.

Hmm, I could think of a few things in your genotype that might produce phenotype differences that affect earthquake survival--Bone thickness, blood clotting, ability to withstand the elements and famine, etc. I just don't think severe earthquakes occur often enough to provide much selection pressure.

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When a roof falls on your head, I don't think the exact thickness of your skull makes much difference.

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"A witty saying proves nothing" Voltaire.
"All your bias are belong to us" Ara Pacis.

I´d place my bets on the ability to detect infrasonic waves preceding a quake. Maybe Mugaliens has something to say about that.

[runs for cover]

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What brings us together is stronger than what pulls us apart