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Someone here wrote "dysgenic breeding and medical progression" and was immediately so heavily downvoted that he removed that comment quickly. Breeding sounds h

Someone here wrote "dysgenic breeding and medical progression" and was immediately so heavily downvoted that he removed that comment quickly. Breeding sounds horrible, and I first needed to google dysgenic, which really makes that term even worse.. but still I wondered not only once: We as civilization with our medical advances (about that I am totally happy) remove or at least change selection pressure, so isn't it inevitable that we partly also "downgrade"? Further, given an illness that kills with lets say 50%, and that is influenced also by genetics: If we can now cure that, so make more people survive and reproduce with this, while factors and genetics stay: isn't it expected we may see this illness raise in the population? Really seriously interested about answers.. there must be a way to properly discuss this? What's the right terms for this? (Besides personally, my gut reaction would also be that change of environment and our lifestyle here is likely most significant factor).

dehrmann 3y ago
On one hand, modern medicine has just put human genetics and fitness at a standstill. On the other, infectious diseases we face have not been standing still.
nonameiguess 3y ago
In general, there are going to be a lot more people reproducing successfully now than compared to a thousand years ago, let alone ten thousand years ago, and some of those people may have genes that would be disadvantageous in a more cut-throat environment that kills a lot of people before they hit breeding age. I can't really say that scans as a plausible major causal contribution to various digestive tract cancers going from 5 per 100,000 to 6 per 100,000 before age 50 from 1990 to 2019. The proposition that any meaningful environmental pressure selected against genes that might cause you to die at 45 instead of 55 doesn't make a whole lot of sense. That is well beyond peak breeding age. These people's ancestors were always susceptible to cancer, but they either didn't live long enough to get it or environmental contaminants that actually trigger the susceptibility were not present. Now they are.
disharko 3y ago
I think it would be fairly easy to find evidence of directly linked survival -> passing on risk. There haven't been so many generations with modern (cancer) medicine that you couldn't trace whether many folks getting cancer young had recent ancestors who survived getting cancer young because of modern medicine. On the other hand, if there's significant overlap between all the historical causes of infant/small child mortality that we've eliminated over centuries, and susceptibility to early cancer, that would be much harder to identify.
GlibMonkeyDeath 3y ago
There is no need to discuss "breeding" in this context at all. The study is over 25 years, a single generation. The germline of any species does not change that quickly. Lots of things in the environment have changed in the last 25 years, though, correlated with any number of things (e.g. obesity.) It will take a while to establish the cause. All the glib hot-takes on HN about "chemicals" and "plastics" might turn out to be a part of the cause, but we will see.
red-iron-pine 3y ago
> Further, given an illness that kills with lets say 50%, and that is influenced also by genetics: If we can now cure that, so make more people survive and reproduce with this, while factors and genetics stay: isn't it expected we may see this illness raise in the population? Illness that doesn't kill before reproduction is irrelevant. Evolution is about spamming copies of yourself more than other strains of organism, and getting cancer at 45-55 is moot if you have 3 kids and a retirement plan mostly completed before then. plus genetically we're still basically cavemen, even if you can find pressures for things like dairy or alcohol tolerance in certain populations.
at_a_remove 3y ago
I believe you are correct. Historically, someone like me would have probably died prior to, say, marriage age. Now, if I wanted to reproduce, I have to ask the big question: do I want to risk saddling my child with what I have? Grandkids? Assuming we don't edit the genes out of embryos and we're not doing something like issuing reproductive injunctions, people with genetic illnesses who aren't particularly conscientious would be adding propensities for whatever to the gene pool. Nobody wants to discuss this because some German people were making noise about the idea eighty years ago and we can't have anything associated with that, to a point of senseless contrarity.

dehrmann 3y ago

On one hand, modern medicine has just put human genetics and fitness at a standstill. On the other, infectious diseases we face have not been standing still.

nonameiguess 3y ago

In general, there are going to be a lot more people reproducing successfully now than compared to a thousand years ago, let alone ten thousand years ago, and some of those people may have genes that would be disadvantageous in a more cut-throat environment that kills a lot of people before they hit breeding age. I can't really say that scans as a plausible major causal contribution to various digestive tract cancers going from 5 per 100,000 to 6 per 100,000 before age 50 from 1990 to 2019. The proposition that any meaningful environmental pressure selected against genes that might cause you to die at 45 instead of 55 doesn't make a whole lot of sense. That is well beyond peak breeding age. These people's ancestors were always susceptible to cancer, but they either didn't live long enough to get it or environmental contaminants that actually trigger the susceptibility were not present. Now they are.

disharko 3y ago

I think it would be fairly easy to find evidence of directly linked survival -> passing on risk. There haven't been so many generations with modern (cancer) medicine that you couldn't trace whether many folks getting cancer young had recent ancestors who survived getting cancer young because of modern medicine. On the other hand, if there's significant overlap between all the historical causes of infant/small child mortality that we've eliminated over centuries, and susceptibility to early cancer, that would be much harder to identify.

GlibMonkeyDeath 3y ago

There is no need to discuss "breeding" in this context at all. The study is over 25 years, a single generation. The germline of any species does not change that quickly. Lots of things in the environment have changed in the last 25 years, though, correlated with any number of things (e.g. obesity.) It will take a while to establish the cause. All the glib hot-takes on HN about "chemicals" and "plastics" might turn out to be a part of the cause, but we will see.

red-iron-pine 3y ago

> Further, given an illness that kills with lets say 50%, and that is influenced also by genetics: If we can now cure that, so make more people survive and reproduce with this, while factors and genetics stay: isn't it expected we may see this illness raise in the population? Illness that doesn't kill before reproduction is irrelevant. Evolution is about spamming copies of yourself more than other strains of organism, and getting cancer at 45-55 is moot if you have 3 kids and a retirement plan mostly completed before then. plus genetically we're still basically cavemen, even if you can find pressures for things like dairy or alcohol tolerance in certain populations.

at_a_remove 3y ago

I believe you are correct. Historically, someone like me would have probably died prior to, say, marriage age. Now, if I wanted to reproduce, I have to ask the big question: do I want to risk saddling my child with what I have? Grandkids? Assuming we don't edit the genes out of embryos and we're not doing something like issuing reproductive injunctions, people with genetic illnesses who aren't particularly conscientious would be adding propensities for whatever to the gene pool. Nobody wants to discuss this because some German people were making noise about the idea eighty years ago and we can't have anything associated with that, to a point of senseless contrarity.