Adaptation to high-altitude hypoxia on the Tibetan Plateau
sciencealert.com
sciencealert.com
https://www.pnas.org/doi/10.1073/pnas.0701985104
> "Tibetans (the study sample were Sherpas, an ethnic group that emigrated from Tibet to Nepal ≈500 years ago) who are born and raised at high altitude have higher capillary density in muscles as compared with Andean high-altitude natives, Tibetans born and raised at low altitude, or lowlanders."
> "Are These Functional Adaptations Heritable? To evaluate the hypothesis that natural selection accounts for the functional physiological characteristics of Tibetan highlanders relative to Andean highlanders or of highlanders relative to lowlanders, a primary consideration is the presence of heritable variation in the traits under consideration. However, the genetic underpinnings of these quantitative traits are mostly unknown (with the exception of nitric oxide). These traits are also influenced by individual characteristics, including age and sex."
> "With respect to identifying specific genetic loci contributing to high-altitude functional adaptation, efforts so far have not been successful."
An accurate headline would replace 'are evolving' with 'might be evolving' for this work.
TIL the human body for the last billion years does not store oxygen in the mitochondria, despite the wide swings in the oxygen levels in the atmosphere, probably due to its destructive effects. In other words: the air is toxic. We breathe it enough, we die.
Oxygen is the oxadative species that drives our biochemistry. It's a fuel.
Oxygen is highly reactive. It is a fantastic evolutionary gradient as it has tons of free and readily available energy to harness. But of course it's also what also wears us down by putting oxidative stress on our cells, DNA, and molecular biology. It causes all sorts of damage as a byproduct of what it is.
Oxygen is life and death.
The particulates suspended in the air are yet another problem ...
Isn’t this true of anything in excess? For gases - nitrogen, oxygen, carbon dioxide, etc all have this effect. In fact some states are using nitrogen for executions, although it’s not exactly humane (warning: https://en.wikipedia.org/wiki/Execution_of_Kenneth_Eugene_Sm...).
What effect are you talking about? Those gases all have very different, unrelated effects.
> In fact some states are using nitrogen for executions
The nitrogen isn't harmful; the cause of death is the amount of oxygen (zero), not the amount of nitrogen (slightly more than normal).
> although it’s not exactly humane
That's just propaganda. Exceptionally dishonest propaganda. You should be ashamed to repeat it.
Cool. Got any reasoning as to why? Here’s mine:
[quote] An autopsy of Smith's body was conducted by the Alabama Department of Forensic Sciences. The autopsy showed Smith exhibited signs of negative-pressure pulmonary edema, had "dark maroon blood" and fluid present in his lungs along with "marked congestion", and had "frothy fluid" in his trachea. Another death row inmate scheduled to die by nitrogen hypoxia in Alabama in November 2024, Carey Dale Grayson, hired an expert to analyze Smith's autopsy results in August 2024. After a review, the expert called the results "highly concerning."[33][34] Dr. Brian McAlary, an anesthesiologist, wrote in an argument on Grayson's behalf that Smith likely panicked due to an automatic response to the inability to breathe oxygen and that Smith's panic may have been avoided if he had been given a sedative prior to his execution. A second expert, Dr. Thomas Andrew, the chief medical examiner of New Hampshire, agreed that Smith should have been sedated before his execution because nitrogen hypoxia introduces "a sense of the absence of oxygen, air hunger, and all of the panic and discomfort that is part and parcel of that way of dying."[34]
Volker Türk, the United Nations High Commissioner for Human Rights, condemned Alabama's use of nitrogen gas to administer Smith's death penalty and stated that the method had amounted to a potential form of torture and degrading punishment.[35][36] [end quote]
> You should be ashamed to repeat it.
Such ad hominem attacks are against the site guidelines.
That actually isn't an ad hominem attack. But you can have one anyway: you are clearly not even slightly concerned with whether the things you say are true. Doing any amount of research would immediately show you that you are - in the very most charitable interpretation - acting as a useful idiot for ideologues. Stop trying to spread blatant falsehoods.
> Dr. Brian McAlary, an anesthesiologist, wrote in an argument on Grayson's behalf that Smith likely panicked due to an automatic response to the inability to breathe oxygen
This is impossible, since no such response exists. The only breathing-related automatic response that humans have is that they become distressed in the presence of excessive carbon dioxide.
That is why every industry that may potentially expose people to low-oxygen environments endlessly repeats the warning: if you go into an atmosphere of all nitrogen (or any other non-oxygen gas, but most commonly nitrogen), you will die without ever realizing that anything is wrong. If you see your friend collapse, do not attempt to rescue them, because you will die too.
That is what people who are rescued from low-oxygen environments report, and it's what is universally observed in the case where somebody is in a position to observe. There is no perceptible difference between breathable air, and air that contains neither oxygen nor carbon dioxide.
> A second expert, Dr. Thomas Andrew, the chief medical examiner of New Hampshire, agreed that Smith should have been sedated before his execution because nitrogen hypoxia introduces "a sense of the absence of oxygen, air hunger, and all of the panic and discomfort that is part and parcel of that way of dying.
Again, this is known to be false, and since both of these people have medical credentials, we can safely say that they are knowingly lying. But you should aspire to be better than they are. There is no such thing as "a sense of the absence of oxygen"; that is not something that humans can feel.
As I mentioned to you, doing any nonzero amount of research would immediately falsify everything you've said.
Here's a discussion of industrial nitrogen accidents: https://www.quora.com/If-you-walk-into-a-room-full-of-100-ni...
> As a safety engineer, I was involved in an incident where nitrogen, N2, had back flowed into a breathing air line. The young man and woman went down, but were observed on CCTV by other workers and pulled to safety. They described their experience as amazing since they had been working in a very quiet, brightly lit green painted room. They said it was like changing the channels on a TV when in the next second, they were on their backs on a cold night looking up at the stars with people standing all around shouting and a fire engine coming up the road with its siren screaming.
> Those two people reported no problems or discomfort at all. One second they were working, the next second they were outside on their backs wondering what the Hell was going on.
Here's an industry flyer discussing the problems involved with using nitrogen: https://www.airproducts.com/-/media/files/en/312/312-12-023-...
> Nitrogen is sometimes mistakenly considered harmless because it is nontoxic and largely inert. However, it can act as a simple asphyxiant by displacing the oxygen in air to levels below that required to support life.
> Being odorless, colorless, tasteless, and nonirritating, nitrogen has no properties that can warn people of its presence.
> At extremely low oxygen concentrations, unconsciousness and death may occur in seconds and without warning.
Are you suggesting that criminals simply have radically different biology than employees do? Were you just hoping that no one would know any facts?
Only in function; they're very different in form. The Tibetan suite of adaptations uses more efficient hemoglobin; the Andean suite uses larger amounts of hemoglobin.
This is generally explained as reflecting the much, much, much, much greater age of the Tibetan suite.
There is a third standard example of a suite of high-altitude adaptations in humans, found in Ethiopian highlanders. For whatever reason, it sees almost 100% less discussion.
Probably because people don't think of Africa as having much extended elevation. And by-and-large, the continent is pretty flat (only Australia and Europe-ignoring-the-Alps are flatter).
It's very difficult to find (or even define) a list of non-mountain high points in the world, but "average elevation of country" (which is only unreasonable for a handful of the largest countries) is easier to find, and Ethiopia is only around 19th place in such lists (17th if we exclude Greenland and Antarctica which are not actually countries), not even the highest in Africa.
Still an interesting article, though!
Lactase metabolism is new, in the last 19k years. European skin colours and blue eyes appear to be very recent too, maybe 3.5k years.
Almost certainly there are all kinds of super interesting human evolutionary changes that are occurring now, with our huge population that won’t be visible for thousands of years…
[0] at least since this https://johnhawks.net/weblog/our-new-paper-on-why-human-evol...
I don't care about living forever, I just want to see what happens in 10k years. Just out of curiosity.
I think there might be more of these effects.
By suppressing the consequence of genetic predispositions and vulnerabilities, it lets those genes propagate more freely and invisibly than they would have been doing before. It helps individuals and communities today in a way we can't possibly refuse, but sets up the species to become perpetually dependent on an elaborate, brittle medical infrastructure. Genetic engineering and eugenics could eventually address that, but those invite scifi horrors of their own. We seem to have set ourselves into a bit of a trap.
How is this any different than the transition from hunter-gatherers to agriculture caused us to "become perpetually dependent on an elaborate, brittle agricultural infrastructure"?
Agriculture took hold in numerous civilizations and indeed introduced one of the primary threats of collapse for those civilizations. Throughout history, we can see civilizations collapse when their dependence on agriculture faltered, which happened often enough.
But neither the technology (agriculture) nor its failures (blight, famine, etc) were universal and so it hadn't become a threat to the species as a whole.
Modernity, however, has become aggressively global and more successfully universalizing. We not only invite every community into it, we insist they do so for their own good. Further, its technological contrivances (and therefore their brittleness) are more intense because of industrialization and later accelerating technology. As it continues to progress and expand, it brings the whole species into its gamble and raises the stakes of that gamble at the same time.
It's hard to know what genes or traits will be advantageous over the next centuries. The biggest place where our technological advantage still has large gaps that our biology can compensate is disease, and there it's almost random -- a gene that results in a novel protein which is normally advantageous or disadvantageous might have the opposite effect if it makes you exceptionally vulnerable or resistant to a new disease.
It is a bit weird to me that the scientific press doesn't talk more about how evolutionary pressure applies here. I think that people are wary to talk about this because it can end up sounding like social Darwinism, or that they believe "Idiocracy" was a scientific documentary.
But it's inescapable, for example, that education rates are now strongly negatively correlated with fertility. While "level of education" is obviously not inherited genetically, I don't think it's too much of a stretch to hypothesize that genetic factors play a role in someone's educational attainment. And, currently, the more education you get, the less likely you are to reproduce (statistically, of course).
Sex evolved to feel really good because for most of human history having sex would usually, eventually lead to babies. Reliable birth control has fundamentally broken that link. Similarly, when a major factor preventing you from reproducing was starving to death, being smarter or cleverer was an evolutionary advantage. I'd argue that advantage no longer exists.
Another simple anecdote: I recently went to my uncle's funeral, and his family was very religious (Catholic). My father, on the other hand, rejected religion and raised us all atheists. My father has 6 descendants, my uncle 24. Again, "religiosity" is not a genetically inherited trait, but I think it would be foolish to believe genetic predisposition plays 0 role.
I say all this just to highlight that, eventually, the "collapse in birthrates" will take care of itself - people with a strong desire and ability to procreate will outcompete, at least in terms of offspring survival, their peers. This will have a huge, profound effect on world society that most academics are too scared to talk about.
You can easily say that city dwelling is strongly correlated with higher education rates, and higher noise pollution, therefore high noise pollution is strongly negatively correlated with fertility. Correlation doesn't equal causation.
> Reliable birth control has fundamentally broken that link.
Reliable birth control has severely reduced unwanted pregnancy, but there's a whole host of people who would like to have children that can't.
I think you're right for the wrong reasons. Correlation does not equal causation. I think it's very clear it's our modern lifestyle. Our diet. Many of us are over weight. Most of us are sedentary. We're consuming higher percentage alcohol and weed. We're consuming other drugs. There are microplastics in our blood stream and the food we eat. There are chemicals like BPAs that were in our products for years before we removed them. Pollution. The list goes on. I would rule out these factors first before ever considering the idea that evolution is at play.
The fact that you have said this makes me think you have misunderstood my point.
I am not arguing that genetic differences are responsible for any change over the past couple generations. I am strongly arguing that there is now an enormous new selection pressure, i.e. a new factor that strongly affects fertility rates, and over time (and, perhaps a very long time) that genetic inheritance will respond to that selection pressure. That is inherently how evolution works.
People love to say "correlation is not causation", but all evolution really works with in the first place is correlation. That is, the environment changes, and then organisms that happen, through "the genetic lottery", to not be able to reproduce in that new environment are outcompeted by those organisms that do. My argument is that the environment that determines whether humans reproduce has changed drastically over the past ~100 years or so, and that this will affect which genes are likely to be more prevalent in the future. I am not arguing this genetic change has already happened.
Far from inescapable, this is just a phantom of noisy data.
It's easy to find statistically communicative population slices where family size is quite high and so is level of education (ignoring that "level of education" is a culturally specific and disputable measure in the first place).
What we really see is that integration into the modern US/EU-inspired "universal middle class" urban culture, which now spans the globe, seems to correlate with lower birth rates and family sizes. But there are countless factors contributing to what makes that culture unique and that could easily be playing a role in the birth rates and family sizes.
That said, it does suggest that the this "modern" culture needs to induct outsiders in order to maintain its scale since its proving relatively poor at growing its own population among insiders. What that means for the future is unclear, and if you're personally all in the on the "modern", it can easily look concerning or even bleak in the way you describe.
Note also that natural selection is about correlation not causality. If an lab accident blows up MIT, that will select against intelligence, even though intelligence wasn't causal.
So, evolution - just framed correctly.
But you can absolutely see evolution across generations of any animal. Humans included.
We are addicted to stories with protagonists, heroes and villains, and so that's how these stories are framed. But that's the exact opposite of what is happening, and everyone knows it, but apparently we just accept it as inevitable.
You could reword it to say that "moths that were more hidden in soot were more likely to survive." But that doesn't change anything? The individual moths involved had no intention. They did not choose to favor genetics that give them a darker look.
I have a pet peeve, which I’m clearly not articulating well, which is that journalistic coverage of this topic relies on two false metaphors: 1) the products of chance can be described as intentional or directed to a positive destination, and 2) a species over time can be anthropomorphized into an individual who has that intent. “How The Rhine Got His Hide,” that sort of thing. Journalists need a story with protagonists and that’s what happens.
That’s my pet peeve, I don’t expect it to bother everyone the same amount, but that’s what my original post was about.
This gets more complicated with actually living things. That is, if you had "How the Ship of Theseus got its mast," I doubt you would necessarily think of any active choices from the ship. See the same for "how chickens came to lay an egg a day" and you would perhaps think there was a bit more active choice on the chickens of old. Realistically, they were both the result of external choices to the subject.
I personally have used the word for many years, and have seen it extensively pre-LLM. To me, it’s only a red flag when someone starts producing content that doesn’t match their prior history of writing with a sudden explosion of vocabulary.
Will male risk behavior be more similar to female risk behavior, 10000 years from now?
Nowadays, the use-case for masculine bravery is more or less obsolete. It had a purpose when there were wild animals roaming around human habitations, but nowadays it may very well trick a man into becoming a war casualty.
Historians of the future might look back on pro-conscription advocates as those who stood in the way of the modern human.
As the world moves back to increased nationalism, some cultures are increasingly militaristic while others become keyboard warriors. Over evolutionary time, that could create different enough human subspecies? Maybe we'll see Klingons after all.
It sounds like you're using a relatively loose definition here. Masculine bravery is not constrained to only the physical realm.
being brave may still be a quality if it's paired with other qualities
10k years is a lot, try predicting what happens in 10 years..
I know several people who have escaped a war-torn country and had a successful life elsewhere, instead of getting affected by military propaganda, and possibly losing everything just because of other people's territorial conflicts.
Edward R. Murrow
What is it with people nowadays, can't there be at least some room for touching this type of sensitive topic?
My post seems to become a downvote magnet. I just wanted to try an unusual perspective that is seldom talked about.
As for general jingoistic propaganda, it's as old as time. I'd also consider it immoral and irrational. Interesting though, as it benefits societies and not (fighting) individuals, and so should have a complex evolutionary dynamics (maybe like with worker bees). _Dulce et decorum est pro patria mori_.
One especially big confound here is remembering the distinction between having sex and having children. From an evolutionary standpoint, the latter is the only thing which matters and unlike animals humans have contraception which completely changes the situation. From an evolutionary perspective the stereotypical bad boy who’s sleeping around constantly might not have even as many children as the cautious, financially stable guy who is monogamous because the former guy’s partners are looking for fun while the latter’s is intentionally trying to start a family.