DNA isn’t so neat as to cleanly separate every change. Thus this could be related to a host of changes that collectively represent a noticeable advantage. With circulatory issues being the #2 killer in the US it’s likely for the circulatory system to be undergoing rapid change.

Increased blood flow to the hand may mean a more efficient circulatory system increasing athletic performance and lowering disease risks etc.

> #2 killer in the US it’s likely for the circulatory system to be undergoing rapid change.

Primarily killing people past reproductive age though.

Those people still influence the young, though. They have a huge impact on their young childrens' diets and habits, and I think epigenetics can throw a wrench into things by affecting how genes are expressed based on environmental factors.

If you're talking about a mutation that will increase the reproductive success of your children(or more likely grandchildren in the case of reduced chance of a heart attack), then the advantage would have to be even greater because of the high chance that your descendants don't have the same mutation.

I'm not saying there's no natural selection occurring, but that saying that heart disease is the #2 killer of Americans out of context likely overstates the selection pressure heart disease causes.

Does it also impact fertility?

Heart disease can impact cognitive function, fertility, economic status, etc well before death.

Yes, but the vast majority of people who die from heart disease don’t develop it until they are older. Which is why it’s misleading to talk about it being America’s #2 cause of death when discussing evolutionary pressure.

Heart disease starts at a young age. Mentioning deaths is relevant to demonstrate how common it is, not that the only impact is death.

No it doesn’t. At least not normally. Google the prevalence rates of heart disease in people under 40.

About 0.6% of people under 40 have the most common type of heart disease

https://www.heart.org/idc/groups/heart-public/@wcm/@sop/@smd...

Again pointing out that it is the 2nd most common killer vastly overestimates its evolutionary impact. The same is true of cancer.

Normal blood pressure increases steadily with age. https://www.idealbloodpressureinfo.com/blood-pressure-chart-... Target and maximum heart rates similarly decline from your teens.

The point where these get called a precursor to heart disease is largely semantics. But they do impact heath before it’s noticeable as a problem.

You’re trying awful hard to save your point.

Target heart rate declining and blood pressure rising with age in no way implies that most people who later die of heart disease are somehow less reproductively fit when they are younger.

You say that, but the connection seems likely which is my point. The indirect symptoms of heart disease such as loss of athleticism and cognitive function would be important.

Heredity is one of the stronger predictors of heart disease so it’s got a strong genetic component beyond diet and lifestyle. So, it’s really just a question of how early meaningful symptoms show up as the physical differences already exist during people’s reproduce years.

It seems like an obvious test if do differences in Forearm arteries have fewer heart attacks. And do they correlate with higher blood pressure in people’s 20’s to 30’x.

>You say that, but the connection seems likely which is my point. The indirect symptoms of heart disease such as loss of athleticism and cognitive function would be important.

Only if as you say the meaningful symptoms show up during common reproductive years.

So far I see no evidence that that is the case.

>Heredity is one of the stronger predictors of heart disease so it’s got a strong genetic component beyond diet and lifestyle.

Again there is no evidence that it is common that hereditary heart disease that generally affects people 50+ has meaningful symptoms during reproductive years.

And there is even less evidence that these symptoms are meaningful enough to impact fertility to such an extent that it creates significant short term evolutionary pressure.

You're taking 1 condition which is common in later life and saying: well maybe some people with that condition actually develop it earlier in life, and just maybe some people that develop it earlier have some externally significant symptoms, and maybe some of those people have specific symptoms that would make them less likely to reproduce all else being equal.

Each step of that funnel is a complete unknown, and each step diminishes the overall impact that genes that control the most common forms of hereditary heart disease have on reproductive fitness.

I agree. There are plenty of reasons why this could be happening, including reasons that have nothing to do with any sort of selection at all. I've updated my comment to clarify what I'm responding to.

Well, Natural Selection doesn’t necessarily mean that only advantageous genes survive the Darwinian hustle, it can also mean that in the absence of negative external pressure also neutral variations are not systematically culled.

It’s like living in a civilized society; you don’t have to worry of starving tomorrow so you take on making art...

Yes, I agree. I'm mostly responding to the authors' speculation:

> “This increase could have resulted from mutations of genes involved in median artery development or health problems in mothers during pregnancy, or both actually. If this trend continues, a majority of people will have median artery of the forearm by 2100.”

It seems like we're on a terrible path with this absence of evolutionary pressure. What's happening to all the babies who survive today that would have died in childbirth had they been born at any time in human history before 100 years ago? Since infant mortality was so high, it must have been an close battle for evolution to keep it under control. Now the brakes are off and whatever mutations were regularly killing babies (and mothers) are now free to propagate to subsequent generations.

Not that that's necessarily a bad thing. We've already evolved to become dependent on technology (cooking, clothing, shelter) and it probably does us good by freeing up our body's resources to do other things better. So perhaps becoming dependent on healthcare for childbirth will eventually happen too and nobody will be worried when women can only give birth by C-section or whatever.

A related issue is immunization. People are so worked up about the politics that they don't want to think about this, but could it be that immunizing ourselves is taking away the evolutionary pressure to maintain a good natural immune system? Multiple generations of measles vaccinated people might end up like the native Americans who were vulnerable from their ancestors having never experienced measles.

This seems like a whole alternative kind of morality - protection of the genes of future generations. But it goes against the popular short term moralities that people have so it seems too objectionable.

I can’t even decide where to start picking apart these arguments... it’s mostly just a “the skies are falling” fear-trip occurring whenever some significantly new status quo emerges.

Sure, literacy made people less willing to spend their lives farming for a pittance, but we managed to industrialize farming and some of those peasant families contributed to society more than a couple loads of bread.

Let’s put it this way: we’re on the path to fully disassemble cellular processes, we won’t need natural selection to tune our immune system when we can design a better one ourselves

Those are valid points. However, immunization has virtually eradicated entire families of diseases with serious, life-altering side effects. I would argue that the short-term benefits outweigh the potential long-term consequences in this case, especially if we continue to vaccinate children against these diseases.

That being said, I think it's far more likely that genetic conditions and predispositions to disease will be resolved through genetic engineering, not natural selection.

Yea, it's not obvious whether we should be sacrificing people today to maybe save future people, especially if we can genetically engineer it all away. But our ancestors (or rather the humans that weren't our ancestors) were certainly sacrificed for our benefit.

I don't think we'll evolve our way out of genetic diseases or we would have already. Rather, it seems like we'll degenerate into higher rates of them without ongoing selection pressure keeping the rate low.

Similar evolution with no selection pressure:

https://www.independent.co.uk/news/science/wisdom-teeth-evol...

I don’t think Darwinism is scientifically established. It has become a bit of a sacred cow because of its opposition with religion, but it is merely a good explanation compatible with the data. That doesn’t prove it. It may be that life evolves and adapts through other mechanism than mere selective pressure.

Selection pressure probably doesn’t apply to evolution in the present tense as evolution is not a conscious entity. Survival of the fittest could have only a past tense application ie the cause of evolution traits surviving. In this case evolution doesn’t know if 3 arteries is good or bad it just happens those people have more kids and their kids have more kids until one day all the 3 artery people die because of some disease where having 3 arteries means you are more likely to die. This will leave 2 artery people living on and from their perspective looking back it’s then selection pressure.

You are assuming this is completely random, and perhaps it is. But the evolutions about wisdom teeth for instance seem logical.

Yeah maybe I don’t know how that could happen though. Epigenetics maybe?

There is no such thing as "Darwinism" outside of Creationist propaganda.

Evolution by natural selection is directly observed in labs, farm fields, and jungles alike. Biologists are not seeking to "establish" it, but to refine it and place it in context with evolution by sexual selection, by genetic drift, by mutualism, and by other influences less well characterized, not least epigenetics, which acts at the scale of individuals.

I.e., lots of "mechanisms" are known. None contradicts any other. What mix is responsible for a change is often hard to tease out.

Darwin wrote about both natural selection and sexual selection. Which do you imagine to be "Darwinism"?

You would better get your information from people not seeking actively to delude you.

I’ve always wondered that. Like why hasn’t evolution itself evolved as well?

evolution itself does evolve. Eusociality or sexual dimorphism, group dynamics and all kinds of complex phenomena obviously weren't present in the primordial soup but are pathways themselves carved out by evolution.

Rate of mutations may change, new mechanisms of evolution may turn up, humans ironically by understanding our genome have acquired the ability to manipulate it in intelligent fashion, and so on.

What has led you to believe that evolution is not itself continuously evolving in each lineage? What do you imagine DNA is for? What do you imagine sex is for? Do you imagine that sexual reproduction always existed, or that it has had no effect on the lineages where it occurs, or their relative prevalence? How do you imagine those lineages became so prevalent, among multicellular organisms?