8 ms·

It's not like people suffering from celiac's disease and eating gluten fail to thrive in our society. They still reproduce and raise families, most people do.

It's not like people suffering from celiac's disease and eating gluten fail to thrive in our society. They still reproduce and raise families, most people do. How is evolution going to improve that situation?

portofcall 9y ago
Evolution doesn’t work like that, it’s not a force with goals except reproductive fitness. In this case our society compensates for their issues, and their reproductive fitness is maintained. In the wild they would disproportionately starve and die, and that would also be a valid evolutionary response. It may also be thst gluten intolerance doesn’t particularly matter to rates of reproduction before it kills you, outside of civilization. If what kills you does so after you pass your genes along, evolution doesn’t even notice. There might be some hidden benefit too, such as with sickle cell and malaria, or more commonly the defective genes are part and parcel of a critical system.
- lxmorj 9y ago
  Food intolerances could help discourage monoculturing, which is a pretty systemic risk to the food supply.
overcast 9y ago
Seeing as we're the only species on this planet that keeps the sick/weak/disabled alive to reproduce. It doesn't fair well in the long term.
- DoubleCribble 9y ago
  Also the only one where the infertile & the dead can reproduce, sometimes together (in vitro + sperm donor). Natural selection has been dealt a mortal blow.
- danieltillett 9y ago
  In the long term we can correct all genetic faults with technology. Natural selection is a very crude tool. What we have more of an issue is smart people are not having children, or not having as many as they can. The only resource in short supply on the planet is smart people.
  - 2snakes 9y ago
    But is intelligence a lethal mutation? Big picture perspective, nuclear arms and environmental degradation...
    - danieltillett 9y ago
      All of those things are a sign we need more, not less intelligence. Given the current selective pressure against high intelligence it is not too wrong to say it is lethal genetic trait.
    - echlebek 9y ago
      The Kurt Vonnegut novel "Galapagos" is about how natural selection selected against intelligence, and the resulting evolution of humans. https://en.wikipedia.org/wiki/Gal%C3%A1pagos_(novel) https://en.wikipedia.org/wiki/Gal%C3%A1pagos_(novel)
- watwut 9y ago
  We are winners of natural selection. And we are not the only ones with compassion, actually. We are only ones with ability to help - maybe there is some evolutionary advantage in that.
ctdonath 9y ago
There are interesting world maps depicting [in]tolerance of various common foods: wheat, milk, alcohol, etc. Humans are adaptively omnivores - those intolerant of one food (when identified) can avoid it via plenty of alternatives. http://www.okwave.com/uploads/attachments/post/image_9/27964/allergymap.gif http://www.okwave.com/uploads/attachments/post/image_9/27964...
gascan 9y ago
Hypothetically we've weakened the selection pressure against those traits, but they still have some impact. A celiac who continues to eat gluten will not be at their best or healthiest. They will have an uphill battle in life compared to everyone else. A celiac who stops eating gluten might spend more on food than other people, minorly impacting their life. (Or, maybe they eat more vegetables than average, and thus being celiac becomes an advantage!?) On a massive population scale, they will on average have some fitness modifier, and their genes will still be selected for or against- just more slowly. Just think of more severe conditions. There are many once-fatal or severely-debilitating conditions where we've enabled people to survive and possibly even reproduce- but the deck is still heavily stacked against them, and they do not on average tend to have large families with lots of successful kids. So a once-fatal trait becomes less severe, but it's still selected against.
danieltillett 9y ago
The evolutionary selection pressure found in modern society is not the same as for most of human history. Celiac's was not a issue before agriculture (no wheat) and the genes responsible have been under negative selection since the rise of agriculture in Europe until about 100 years ago. Agriculture was so recent that non-adaptive genes have not been fully removed from the population, nor have adaptive ones (like digesting lactose in adulthood) fully spread through the population. Humans were part way through a massive selective sweep (adaption to agriculture) when the industrial revolution happened. If this had taken 100,000 years rather than 10,000 years then Celiac's would have become almost non-existant.
- sitharus 9y ago
  In addition to lacking wheat pre-agriculture there's a reasonable amount of evidence that the modern increase is due to the elimination of gut parasites - previously the increased immune activity in the gut was beneficial (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4403024/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4403024/). There's also some research that suggests modern high-gluten wheat varieties have more of the proteins that trigger coeliac disease (https://www.nature.com/articles/srep44609 https://www.nature.com/articles/srep44609)
jamesrcole 9y ago
> It's not like people suffering from celiac's disease and eating gluten fail to thrive in our society. They still reproduce and raise families, most people do. I think that's an interesting empirical question. The question is the degree to which their genes propagate vs people without celiac disease. There seems to be a generic component to celiac disease, so obviously the effect can't be strong enough to wipe out the disease (and also worth remembering that there may be positive effects of those genes), but does it actually affect their evolutionary fitness to some degree? (and I think you'd find many people with celiac disease would say that it makes it difficult for them to thrive, in a more everyday use of the term 'thrive')

portofcall 9y ago

Evolution doesn’t work like that, it’s not a force with goals except reproductive fitness. In this case our society compensates for their issues, and their reproductive fitness is maintained. In the wild they would disproportionately starve and die, and that would also be a valid evolutionary response. It may also be thst gluten intolerance doesn’t particularly matter to rates of reproduction before it kills you, outside of civilization. If what kills you does so after you pass your genes along, evolution doesn’t even notice. There might be some hidden benefit too, such as with sickle cell and malaria, or more commonly the defective genes are part and parcel of a critical system.

lxmorj 9y ago
Food intolerances could help discourage monoculturing, which is a pretty systemic risk to the food supply.

overcast 9y ago

Seeing as we're the only species on this planet that keeps the sick/weak/disabled alive to reproduce. It doesn't fair well in the long term.

DoubleCribble 9y ago
Also the only one where the infertile & the dead can reproduce, sometimes together (in vitro + sperm donor). Natural selection has been dealt a mortal blow.
danieltillett 9y ago
In the long term we can correct all genetic faults with technology. Natural selection is a very crude tool. What we have more of an issue is smart people are not having children, or not having as many as they can. The only resource in short supply on the planet is smart people.
- 2snakes 9y ago
  But is intelligence a lethal mutation? Big picture perspective, nuclear arms and environmental degradation...
  - danieltillett 9y ago
    All of those things are a sign we need more, not less intelligence. Given the current selective pressure against high intelligence it is not too wrong to say it is lethal genetic trait.
  - echlebek 9y ago
    The Kurt Vonnegut novel "Galapagos" is about how natural selection selected against intelligence, and the resulting evolution of humans. https://en.wikipedia.org/wiki/Gal%C3%A1pagos_(novel) https://en.wikipedia.org/wiki/Gal%C3%A1pagos_(novel)
watwut 9y ago
We are winners of natural selection. And we are not the only ones with compassion, actually. We are only ones with ability to help - maybe there is some evolutionary advantage in that.

ctdonath 9y ago

There are interesting world maps depicting [in]tolerance of various common foods: wheat, milk, alcohol, etc. Humans are adaptively omnivores - those intolerant of one food (when identified) can avoid it via plenty of alternatives. http://www.okwave.com/uploads/attachments/post/image_9/27964/allergymap.gif http://www.okwave.com/uploads/attachments/post/image_9/27964...

gascan 9y ago

Hypothetically we've weakened the selection pressure against those traits, but they still have some impact. A celiac who continues to eat gluten will not be at their best or healthiest. They will have an uphill battle in life compared to everyone else. A celiac who stops eating gluten might spend more on food than other people, minorly impacting their life. (Or, maybe they eat more vegetables than average, and thus being celiac becomes an advantage!?) On a massive population scale, they will on average have some fitness modifier, and their genes will still be selected for or against- just more slowly. Just think of more severe conditions. There are many once-fatal or severely-debilitating conditions where we've enabled people to survive and possibly even reproduce- but the deck is still heavily stacked against them, and they do not on average tend to have large families with lots of successful kids. So a once-fatal trait becomes less severe, but it's still selected against.

danieltillett 9y ago

The evolutionary selection pressure found in modern society is not the same as for most of human history. Celiac's was not a issue before agriculture (no wheat) and the genes responsible have been under negative selection since the rise of agriculture in Europe until about 100 years ago. Agriculture was so recent that non-adaptive genes have not been fully removed from the population, nor have adaptive ones (like digesting lactose in adulthood) fully spread through the population. Humans were part way through a massive selective sweep (adaption to agriculture) when the industrial revolution happened. If this had taken 100,000 years rather than 10,000 years then Celiac's would have become almost non-existant.

sitharus 9y ago
In addition to lacking wheat pre-agriculture there's a reasonable amount of evidence that the modern increase is due to the elimination of gut parasites - previously the increased immune activity in the gut was beneficial (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4403024/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4403024/). There's also some research that suggests modern high-gluten wheat varieties have more of the proteins that trigger coeliac disease (https://www.nature.com/articles/srep44609 https://www.nature.com/articles/srep44609)

jamesrcole 9y ago

> It's not like people suffering from celiac's disease and eating gluten fail to thrive in our society. They still reproduce and raise families, most people do. I think that's an interesting empirical question. The question is the degree to which their genes propagate vs people without celiac disease. There seems to be a generic component to celiac disease, so obviously the effect can't be strong enough to wipe out the disease (and also worth remembering that there may be positive effects of those genes), but does it actually affect their evolutionary fitness to some degree? (and I think you'd find many people with celiac disease would say that it makes it difficult for them to thrive, in a more everyday use of the term 'thrive')