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Mutations Helped Humans Survive Siberian Winters
sciencehabit writes "Researchers have identified three genetic mutations that appear to have helped humans survive in the frigid climate of Siberia over the last 25,000 years. One helps the body's fat stores directly produce heat rather than producing chemical energy for muscle movements or brain functions, a process called 'nonshivering thermogenesis.' Another is involved in the contraction of smooth muscle, key to shivering and the constriction of blood vessels to avoid heat loss. And the third is implicated in the metabolism of fats, especially those in meat and dairy products—a staple of the fat-laden diets of Arctic peoples."
Correct me if I'm wrong, but I thought the ability to process dairy was a more recent addition to the human species than 25k years ago. Or am I just being to damn pedantic?
I learned this from a Sauron Cyborg on Tanith.
I can do the same thing with Rockstar and CHEETOS.
I can think of one trillion-dollar industry that might be interested in knowing how to cause 'nonshivering thermogenesis' in fat cells on demand...
It's clear from the story, that UCP1 and UCP3 would give them an unfair advantage!
What functionality was there before the mutation?
I would find that very interesting.
Kill them with fire! They're the spawn of The Thing!
...gis sdrawkcab (usually not responding to ACs; don't bother posting as AC)
I read a theory once that I found interesting: that arterial plaque is a legacy of survival in an ice age or in an extremely cold environment like Siberia.
Here's how it goes, from memory: Humans get antioxidants from plants, but in extreme conditions plants were less available and humans may not have gotten enough antioxidants. Absent the antioxidants, free radicals posed a greater health risk.
Arterial plaque provided some defense against the deleterious effects of the free radicals, and helped the humans survive the freezing times... long enough to reproduce. Maybe in middle age the hardening of the arteries had deleterious effects of its own, but evolution is all about what helps reproduction, not so much what helps the individual live to a ripe old age.
This sounds sort of plausible but I don't have the background to evaluate it. It could also be one of those "wet streets cause rain" theories that invert cause and effect... is arterial plaque not the body's defense against free radicals but simply damage caused by them?
Mutations helped people survive. (- that is a period)
That fat chick is really hot!
(I'm sorry. One day these cries for help will be heard by the right people.)
In Russian Siberia, fat stores you!
just drink more vodka ... helps you stay warm and is good antifreeze
1. Just like the article says and unlike the Slashdot summary suggests, shiver-free thermogenesis is old and all mammals share it.
2. The researchers found traces of positive selection in a gene involved in shiver-free thermogenesis.
3. How do you look for traces of selection? A mutation in a DNA fragment coding for a protein can have two effects: either it changes the corresponding amino acid in the protein sequence (non-synonymous mutation), or it does not (synonymous mutation). This is because genetic code is redundant and different codons code for same amino acids, so a change from one codon to another does not have to change the protein. Synonymous mutations are assumed to be neutral for evolution (although they are not, not always).
Now, if you look at many possible variants of a gene and collect many different mutations, you can calculate whether the ratio of non-synonymous to synonymous mutations (called the dN/dS ratio) is (i) higher (ii) lower or (iii) quite like expected. Depending on the outcome of the test, you can say:
- if it is higher than expected, then there is a positive selection force at work (the gene is pushed towards change)
- if it is lower than expected, then we have a case of purifying selection; the gene is being actively maintained as it is, and any non-synonymous mutations are being removed from the population
- if it is neither lower nor higher, the gene is just not important
4. So, nice, you found that a gene related to non-shiver thermogenesis shows traces of positive selection. So what?
The answer is, not much. You do not always know which mutation was the one being selected. And even if you can pinpoint it, very often you will not be able to say what it actually does. So fine, you have a leucine replaced by arginine at position 186 in a protein chain; you might be able even to model the new sequence and see a delicate shift in the structure of the protein. How does it relate to the protein function? What has been modified or improved? No idea.
5. OK, why is that important? It is important because much of the genetic variability of the humans that we know is thought to have been fixated by genetic drift and other neutral evolutionary effects (like surfing the wave of colonization) - rather than selection. There are few examples of selection known. Light skin is one of them, and is thought to be an adaptation to the vitamin D deficiency caused by lack of sun at high latitudes. Mutation that keeps lactase being produced throughout life is another one. There were independent (convergent) events in both cases, by the way.
Look, humans are special. Special in the sense that humans are genetically extremely uniform, and the genetic differences between, say, native Australian, a blond-haired, blue-eyed Swede and a member of the Mbuti people from Africa are all together much smaller than between two chimpanzee individuals from groups living a few hundred kilometers apart. And moreover, these few mutations specific for some people but not for other seem to be more or less neutral in their character.
Finding differences that are *not* neutral, that are actually doing something is therefore an interesting thing. Notably, the few existing differences like that are linked to mundane things like metabolism or immune response (yes, some people are special because they don't fart after drinking milk, how is that for a superior race), and not, for example, to cognitive and brain development. The latter differences are found between humans and other primates.
It wouldn't surprise me if I had one or more of these mutations.
I find temperatures above 21C unpleasant. In December, I slept a couple nights in -25 temperatures in a -12 rated sleeping bag and was perfectly comfortable. I rarely wear a jacket above 0. I've taken a 45 minute casual swim in 10 water in nothing but shorts and felt a little chilled but fine (though it was sunny).
But I pay for it in the summer. Once it hits 23 my brain slows down. Around 26 it completely shuts off. I've experienced temperatures up to 40, but I'm glad those days are rare.
It's easy for me to overheat. I went on a winter hike in -15 weather and ended up getting moderate hypothermia -- because I left dressed in a "normal" amount of winter wear and sweat my clothing through. I was steaming. Thankfully I had a change of clothes, and two hours in a -7 sleeping bag got me warmed back up to normal.
People think I'm weird for enjoying -30. But I'd much rather have that than 30. I still find it odd that much of the world lives in near-constant 30 and find those high temperatures comfortable.
Be relentless!
... just saying
Mutations that are good for living in cold weather are probably bad for living in hot weather.
You don't want your body fat turning itself directly into heat if it's hot outside anyway.
But if you're living in Siberia you don't really have to worry about hot weather.
Brown adipose tissue
That's the right title: "only people with mutations survived".
It's not like humans mutated into something so that they could survive in Siberia but rather that humans who happened to have some mutations could survive and all the others died.
That small difference in wording is what defines natural selection (Darwinism, right) vs traits inheritance (Lamarckism, wrong).
... would be for body fur/hair to re-emerge? I wonder why this didn't happen? Ok , obviously they're wearing clothes and had fire but if you're STILL cold even with that assistence then surely having more body hair would help you keep warmer? Yet the asian peoples including those in siberia are LESS hairy than other races. Strange.
Same with me, I can stand the cold better than warm weather where I can just swim away in my sweat. :-/
I've always suspected it came from having one half of Finnish genes.
home
I have a mutant ass. Would you like to fuck it?
Goatse? THERE you are. Been looking all over for you baby. C'mere!
How many more nails in the coffin of "human races do not exists" and "ethnic differences are just skin deep" nonsense statements do we need before we all demand politics stay the funk off science?
Refusing to look into Galileo's telescope has always proved dangerous and wrong, no matter how many priests shouted "looking is evil"
There, fixed it.
How many will it take to shut people like you up?
You can father a child with any female individual from one of these groups and that offspring will be able to breed with any of the people in our world, so on and so forth. Of course there will be genetic variants expressed. That is normal and desirable in any population - we really need more diversity and mixing, not less. As a species we need as much opportunity to recombine genetics in favorable ways as possible (with inevitable unfavorable combos happening occasionally as well).
Any other approach would be regressive, prone to conserving bad mutations over good (6 fingers sound familiar?) and generally irresponsible.
A fool throws a stone into a well and a thousand sages can not remove it.
I dont see that he said anything outlandish to desrve hatred. He simply argued against the position of "races dont exist". He has a point; the races do exist, and they bring with them certain biological differences. And since that's all he said, I think you're overreacting a bit. Let's wait until he actually says something bigoted before crucifying him for it.
The guy who said the election was rigged won the presidency with the second-most votes.
Why would you have to lose anything?
Some mutations offer no advantage only a disadvantage. Why can't one just be an advantage without a trade-off. It is not like real life is like a Video Game or D&D where there is a goal for balance. Sometimes things are just better or worse than before.
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
I am sorry to inform you that the real goatse died a few years ago. Start mirroring before that part of our shared heritage disappears forever.
What is your muscle mass % like? Depends on the build/lifestyle, your BMR can be really working well for you there.
"Fat burning Sineria"- specially in Winter
What are the tradeoffs associated with these mutations?
In general, when you have a benefit, it's offset with a negative somewhere.
Also, now there are epigenetic effects. Maybe it's not a mutation at all, just a difference in expression?
Right now I'm carrying a fair amount of extra weight, but even when I was trim my temperature preferences were the same (I took the swim at the skinniest point in my adult life when I was buying shirt to fit my chest).
Be relentless!
Mutations that are good for living in cold weather are probably bad for living in hot weather.
You don't want your body fat turning itself directly into heat if it's hot outside anyway.
But if you're living in Siberia you don't really have to worry about hot weather.
No quite true. Siberia during ice age and Siberia today are two different climatic patterns. Nowadays it is not unheard of to experience up to 40C during spring/summer. So people fit to withstand cold are going to suffer during heat waves.
Sounds about right for me as well, thankfully not to quite the same degree as you. I overheat easily, like for instance riding my bicycle even in winter weather with just a regular jacket on. Forget about bicycling for long distances in summer, even in shorts and a t-shirt, I'm sweating like mad in minutes.
I have a theory that this is related to my inability to get below ~95kg. I work out hard 3-4 times per week (hard ~1 hour crossfit workouts), I always take the stairs, I've all but eliminated white rice, white bread and other simple carbs from my diet, I've cut down severely on my serving sizes, I've pretty much cut out all snacks completely (apart from the occasional piece of dark chocolate, one is human after all), I hardly ever touch alcohol and never in large amounts, and yet my weight stays right where it is.
I know my weight will balloon upwards if I start eating badly again (I was over 120kg at one point), but my current body fat percentage is ~30%, my BMI is ~30 and I just can't get rid of my belly etc. seemingly no matter what I do.
But at least I'm never cold, I guess.
Eat the rich.