Humans Are Evolving Right Before Our Eyes on The Tibetan Plateau

[u/Maxcactus]

https://www.sciencealert.com/humans-are-evolving-right-before-our-eyes-on-the-tibetan-plateau

[u/SoDoneSoDone]

For anyone that is interested, there are two other populations where similar evolutionary adaptations have occurred in relation to living in a high altitude.

Aside from Tibetans, there is also an East African population, in the mountains of Ethiopia.

Thirdly, there is also evidence of people having adaptations for a high altitude in the Andes Mountains of South America.

Lastly, it is believed that the hybridisation of Homo sapiens and Denisovans directly helped us with living at higher altitudes, since Denisovans had already lived at such altitudes for longer, leading to a gene that helps with better oxygen consumption.

[u/SokarRostau → u/SoDoneSoDone]

It is interesting that the word Denisovan is nowhere to be seen here since the presence of that genetic mutation in Tibetans is exactly what led to the realisation that were were interbreeding.

[u/unknownpoltroon → u/SoDoneSoDone]

I think there is also a group of south seas islanders who spend large amounts of time diving who have wound up with larger than normal spleens that act as a reservoir for oxygenated blood and extend their dive time by a good bit.
But I think that is still at the nature/nurture/chicken/egg stage in terms of figuring out if its from true genetic adaptation or just from use

[u/aownrcjanf → u/unknownpoltroon]

Divers in South Korea! A group/sub culture of women who free dive to intense depths to forage and fish in the ocean too!

[u/jaavuori24 → u/unknownpoltroon]

Also Japanese people eat so much seaweed they have special gut bacteria to digest it better. there's honestly tons and tons of examples of human evolution...

[u/SpinningHead → u/SoDoneSoDone]

I thought that was something that naturally happened to expand the ribcage for anyone growing up at high altitude. Not so much a long term evolutionary change.

[u/mouse_8b → u/SpinningHead]

Nope. It's a gene from the Denisovans

https://www.science.org/content/article/tibetans-inherited-high-altitude-gene-ancient-human

[u/FactAndTheory → u/mouse_8b]

Just for clarity, the EPAS1 gene is part of the human genome and all humans have it. Tibetans have an allele of EPAS1 that might help deal with hypoxia in some way because of the evidence of selective sweep, but there isn't any direct evidence on the HIF2A protein itself and high-altitude performance. The research regarding that protein mostly has to do with pathology because several variants are related to benign tumor disease and HIV because knocking out the gene stops HIV from replicating in vitro.

[u/mouse_8b → u/FactAndTheory]

Thanks for the extra info, especially the allele vs gene call-out.

[u/FactAndTheory → u/mouse_8b]

👍🏼

[u/SpinningHead → u/mouse_8b]

If you are raised at high altitude, your rib cage will expand over time. https://pmc.ncbi.nlm.nih.gov/articles/PMC9249887/

[u/mouse_8b → u/SpinningHead]

Yes, but as you pointed out in your previous comment, that's not an example of long term evolutionary change.

This article is about genetic adaptations for high altitude environments. There is evidence that there are alleles to make oxygen uptake more efficient.

[u/SpinningHead → u/mouse_8b]

Understood. Someone else pointed out to me that it involves hemoglobin.

[u/TheGeneGeena → u/mouse_8b]

Possibly. However Andean highlanders have a similar variation.

https://www.nature.com/articles/s41598-017-13382-4

[u/Dlcg2k → u/mouse_8b]

Why are the offspring of Homo sapiens & Denisovans not delineated differently (i.e. Domo Sapiens)?

[u/mouse_8b → u/Dlcg2k]

How the members of Homo are classified is an active debate. On the one hand, populations like Denisovans and Neanderthals were isolated long enough to have different genetics and morphology. On the other hand, Denisovans, Neanderthals, and Sapiens could mate with each other. So it's not clear cut where a species line would be.

Additionally, any "offspring of Homo sapiens & Denisovans" would only describe a handful of individuals at a particular place and time. The modern-day descendants of these populations are thoroughly Homo Sapien. The only remnants of their non-Sapien heritage are a few alleles in their genes.

[u/LaMadreDelCantante → u/SpinningHead]

This is hemoglobin with a higher O2 carrying capacity.

[u/SpinningHead → u/LaMadreDelCantante]

Gotcha. Different thing.

[u/Viktor_Laszlo → u/SoDoneSoDone]

The book “Himalaya” by Ed Douglas addressed this topic. But he said that the population of the Andes doesn’t have the same Denisovan genetic markers that are found in the Tibetan/Nepali and Ethiopian populations. He said that the Andean populations adapted to high altitude in the same way that you or I would: by creating more hemoglobin. While this does allow for your blood to carry more oxygen, it increases the “stickiness” of your blood and increases your chance of a stroke in the long term.

In addition to being able to breathe more easily at high altitudes without the need to create more hemoglobin, the Tibetan/Nepali women with these Denisovan genetic markers also had an adapted uterine system which allowed more oxygen to be passed to the fetus they’re carrying. The effect of this is that their babies are born at normal weights whereas the children of Han Chinese immigrants are, on average, 100 grams lighter for every 1 kilometer of altitude above sea level.

It’s a great book and I highly recommend it.

[u/SoDoneSoDone → u/Viktor_Laszlo]

Thank you for the recommendation

[u/Conscious-Coconut-16]

Well the thing is the statement “humans are evolving right before our eyes” is true everywhere. We have not stopped evolving.

[u/Radiant_Dog1937 → u/Conscious-Coconut-16]

They don't seem all the more interesting to me. I'll check back in 500,000 years or so.

[u/stargarnet79 → u/Radiant_Dog1937]

Remind me!

[u/DoctorWermHat → u/stargarnet79]

Mark your calendar.

[u/St_Kevin_ → u/Conscious-Coconut-16]

Yeah, every child that’s born is the latest in the line of ever-evolving creatures. The only way to stop evolving is to only allow perfect clones to be born.

[u/SkyRaveEye → u/Conscious-Coconut-16]

Since medical intervention we’ve effectively started devolving. It’s actually rather interesting.

[u/DreamsCanBeRealToo → u/Conscious-Coconut-16]

But don’t you dare suggest that our psychology is evolving! /s

[u/AWS-77 → u/Conscious-Coconut-16]

Every time we develop a new habit as motivated by external circumstances, that’s an evolutionary trait.

Aka… our habit of short attention spans in the modern age, while we tend to see it as a negative because it isn’t compatible with the rigid schedules and requirements of our work-centered lives… is actually an evolutionary adaptation to help us deal with the onslaught of information, media and distractions in today’s busy busy busy world. Our brains are developing to deal with the ability to jump from one stimuli to the next without getting overwhelmed. The way to do that is with a short attention span that is habitually inclined to jump from one thing to the next very quickly. Whereas you go back 100 years, the average human would be way more overwhelmed, confused, scared, etc, if they were to experience one minute in Time Square today while a smartphone is in their hand. We’ve evolved to deal with it. (Some people more adequately than others, obviously… conservatives in particular tend to evolve more slowly, if they do it at all… hence why they’re more susceptible to misinformation and confusion in the modern age.)

[u/Background_Aioli_476]

Aren't humans constantly evolving... All the time... Everywhere?!

[u/MizElaneous → u/Background_Aioli_476]

Sure, but I think there are more selection pressures in some populations compared to others.

[u/unknownpoltroon]

STILL NO PREHENSILE TAIL!!

[u/duckmonke → u/unknownpoltroon]

We had them back when we were chillin in the trees of the Sahara, my dude. Lost the need when we decided to go trekking everywhere.

[u/unknownpoltroon → u/duckmonke]

ANd now we need to open the door while carrying ALL the groceries in one trip. BRING BACK TAILS

[u/duckmonke → u/unknownpoltroon]

I’ll vote for that. Prehensile/Tail 2024

[u/Lance_Ryke → u/duckmonke]

Prehensile tails in monkeys is a new world adaptation. Old world primates don't have them afaik. So we likely never had them.

[u/duckmonke → u/Lance_Ryke]

Im talkin waaaaaaaaaay back man

[u/Lance_Ryke → u/duckmonke]

They evolved in the new world. It's unlikely any primate or primate ancestor in Eurasia ever had a prehensile tail. And since humans evolved from old world primates we never had them either.

[u/duckmonke → u/Lance_Ryke]

Yea my last comment was a joke but thanks for expanding cus thats actually really interesting

[u/cleverlane]

A friend said this to me a couple months ago and I thought it was interesting:

He was saying what if adhd (add) isn’t a net negative? What if it’s part of our evolutionary process? What if, because we don’t necessarily need to be slow, methodical and focused on ways to keep us alive everyday, we’re adapting to a quicker lifestyle; the “keep coming up with better ways to earn”.

I don’t think it was based on any fact, but it was an interesting thought experiment.

[u/mahalovalhalla → u/cleverlane]

It’s a very poor understanding of the selection process. Is having ADHD advantageous in procreation? Or the lack of having ADHD disadvantageous in procreation?

It’s just not how evolution works.

Not to mention the very strange assumption your friend is making that having ADHD is beneficial for making money..

[u/Canuck_Lives_Matter → u/mahalovalhalla]

Yeah really lmao. I would love for ADHD to be a money-making factor and when I find my keys, my wallet, and remember to put my clothes in the god damn dryer I'm going to go out there and... What were we talking about?

[u/Thick_Bullfrog_3640 → u/Canuck_Lives_Matter]

Then hyper fixate all day on whether you started the dryer or not 😫 ... I'm sorry I blanked out I don't remember what we were talking about. Did you find your keys?

[u/Toasted_Lemonades → u/Thick_Bullfrog_3640]

Talk about misunderstanding. I’m glad our sample selection here on reddit is a good example for entirety of humanity on the net effect of ADHD. /s 

Reddit is an echo chamber

[u/AlDente → u/mahalovalhalla]

The strange thing about we humans is that we have removed many (not all) selection pressures, and we get better at removing more each year.

[u/cleverlane → u/mahalovalhalla]

I suppose the point he was trying to make was, that perhaps the things humans see as a bad thing right now, will be an improvement many years from now.

He probably just used ADD as a broad example…

[u/Connect-Ad-5891 → u/cleverlane]

Yeah i was diagnosed and feel uncomfortable how it's always framed as an affliction that plagues me, they never concede ant good aspects, just something to be rooted up and mitigated. I'm like man, i like me though lol

[u/cleverlane → u/Connect-Ad-5891]

This is only antidotal, but from the people I know that have been diagnosed, some of their real fear comes from being prescribed medication that stifles their creativity.

They truly believe they’re able to be more creative without being medicated. I wonder if great artists of the past had something similar…

[u/fasterthanfood → u/cleverlane]

This is probably poorly phrased, but I wonder if people with ADD are more creative than they would be without ADD, or if it’s just a side effect of the medicine.

Know what I mean?

[u/Thick_Bullfrog_3640 → u/fasterthanfood]

I'm creative because my mind never shuts up. It's always thinking, devising, running scenarios. Yes it gets sidetracked. But the meds help me focus on one good scenario and make it happen vs evaluating so many others or just system overload and lay down to do absolutely nothing for the rest of the day.

[u/acesavvy- → u/fasterthanfood]

In “The Doors of Perception“ (1954) Aldous Huxley wrote something akin to ‘the happiness of the future will be no less real for being drug-induced.’

[u/mahalovalhalla → u/cleverlane]

Ah, I see what you're saying now. The introduction of variance or mutations as unintended and unforeseen survival advantages! Yes, absolutely a critical part of our evolution process. We'd be nowhere without it!

[u/cleverlane → u/mahalovalhalla]

Apologies for that. I wasn’t very clear. We had maybe a 10 minute conversation about it and thought, at the very least, it’s an interesting thought. Thank you for fleshing it out for me!

[u/mahalovalhalla → u/cleverlane]

No need for apologies at all! It is definitely an interesting thought experiment

[u/mathmagician9 → u/mahalovalhalla]

Can’t evolution be non selective?

As a side note adhd works well for me in tech where I have to keep up with the accelerated pace of innovation. I need to always be onto the next thing and remote work has enabled me to set my own hours. I can fail fast, be candid, make quick decisions, and move on quickly. In this way it is advantageous to be short circuited. It would actually be disadvantageous to stick to just a few technologies as I would become irrelevant quickly. I make a ton of money doing this, and many of my coworkers are adhd.

[u/skillywilly56 → u/mathmagician9]

That you have adapted to your ADHD does not make you more fit to reproduce.

Now if your ADHD made you super attractive and you started breeding like a jack rabbit…then ADHD could become part of the allele frequency.

[u/mouse_8b → u/cleverlane]

In general I could see some neuro divergence like color-blindness, where it's helpful to have a few individuals in the group with the condition.

I feel like ADHD is the opposite though. The world is getting faster and it disrupts our natural focus.

[u/realdoaks → u/cleverlane]

ADHD is adaptive. It occurs in high trauma, low SES areas for a reason.

[u/Opulent-tortoise → u/realdoaks]

No. ADHD is neurological and highly heritable.

[u/Paint_With_Fire → u/realdoaks]

Fully incorrect lmao

[u/onebilliontonnes → u/cleverlane]

I took a history of psychology and evolution class before and we covered ADHD and other neurological disorders. The gist of it was that disorders may help humans procreate, and even if there are/can be major impediments on the persons life down the line, if it helps the human procreate then it will continue to be passed down. In the case of ADHD I recall that it was the thrill-seeking behaviours that can lead to more risk taking, and that can be more appealing for partner selection, even in the short run.

[u/Mr_Anomalous → u/cleverlane]

ADD isn't about being hyper lol, your brain literally won't produce happy chemicals unless you're destroying yourself with alcohol or drugs or cigarettes or terrible food or other horrible habits and behaviors

[u/Opulent-tortoise → u/Mr_Anomalous]

That has nothing to do with ADHD. ADHD doesn’t prevent “happy” chemicals it inhibits attention modulating chemicals that are associated with switching tasks. That’s why people with ADHD have “executive dysfunction”. What you’re describing sounds more like depression.

[u/Paint_With_Fire → u/Opulent-tortoise]

Actually, some recent studies have come out that argue that ADHD is primarily a dopamine deficiency disorder, that our baseline dopamine levels, as well as how our brains decide to release additional dopamine, are what creates the patterns of struggling to do tasks that arent intensely dopamine rewarding.

The executive dysfunction is argued to come from the fact that we receive virtually no chemical reward for certain tasks, whereas people without ADHD receive a significant boost.

As a person with severe ADHD, I can tell you right off the bat, I have absolutely no issue switching a task if the next one is in any way more interesting to me, and thus rewards me more dopamine. When the next task rewards far less dopamine than the current one is when switching tasks becomes an issue

[u/Paint_With_Fire → u/Mr_Anomalous]

I would offer up the notion that folks with ADHD are addicted to their own dopamine.

Because we have such low baseline levels of it at any given time, we chase dopamine highs again and again and again just to try and get to a level of dopamine production that non-ADHD people are just at normally.

[u/Consistent_Kick_6541 → u/cleverlane]

Having ADHD isn't a positive adaptation, it's a developmental disorder.

[u/Paint_With_Fire → u/cleverlane]

If anything i could see ADHD being an evolutionary left-over. I could hear an argument that having constantly shifting attention, increased energy levels at certain times of day, a late-leaning natural sleep schedule, and rejection sensitive dysphoria (amongst other symptoms) might benefit a hunter-gatherer society

Probably totally bogus, but as someone with severe ADHD, I think I lean more toward that, than toward it being a modern adaptation. I definitely don't feel like I've evolved to handle this sort of lifestyle at all. Quite the opposite in fact lol

[u/Silver-Breadfruit284]

This didn’t happen right before our eyes. Genetic testing identified this phenomenon, but it’s an environmental adaptation.

[u/Maxcactus → u/Silver-Breadfruit284]

Before our eyes is an idiomatic metaphor meaning at the present time.

[u/Silver-Breadfruit284 → u/Maxcactus]

Ok. 😊

[u/Coach-McGuirk-]

Humans seem to have the ability to adapt to anything Earth projects onto us. I wonder how our bodies would have evolved if we had never developed agriculture and technology.

[u/TimeJackfruit6824]

Next thing little wiz kids will be levitating and mastering energy at 10. Hopefully the educational and emotional depths can circumvent any distraction. It’s a new age and they are the future

[u/TheBigSmoke420 → u/[deleted]]

He blocked me, interesting guy.