Meanwhile, 140k years ago, our 3rd civilization approached our current level of tech. Fashion designers, specifically a group lead by Argot the Great, decided the tail made pants difficult, and broke the lay of suit jackets.
So they hired radicals to genetically engineer a retrovirus, to remove the tail. This worked, but due to unconsidered balance issues, all tail devoid children lost the capability for bipedal balance and therefore walking.
Most of these children, during their formative years spent their time on all fours, and thud their hand dexterity was pitiful, and society crumbled when they came of age.
It was another 46k years before a brain mutation emerged, re-enabling bipedal balance, but by that time all traces of the old civilization was lost, and thus, progress began anew.
Rarely is human genetics this simple. For ages geneticists thought large swaths of the human genome were "junk" and over time more and more of it has been proven to have a purpose or function, it just wasn't readily apparent for various reasons.
Think of the human genome as sort of the ultimate dependency hell...
Nature does not refactor. There's the laryngeal nerve somewhere in the neck of mammals that has to go around a blood vessel. On Giraffes, this runs all the way down the neck, around said blood vessel, than back up, all that just to connect two places in the upper neck that are inches apart. Evolution writes the ultimate spaghetti code.
Early developmental biology (by “early” I mean early pregnancy) is the shit you Do Not Touch. Each step of development is highly dependent on the previous steps (assuming this bit’s here, that bit’s there, etc.). If you make a change it’s extremely likely to be fatal or have negative consequences like birth defects, and the likelihood of a bad outcome climbs steeply as you move the change earlier and earlier in the process. That’s why pretty much every animal - humans, tigers, whales, lizards - looks the same when they’re a teeny tiny little fetus.
My example is testicles! Testicles begin in the same place as ovaries, which made a lot of sense back when we were coldblooded! Having a pair of balls dangling in a soft pouch between your legs isn’t a strategy you adopt if you can help it. In the alternate timeline where lizard people rose to dominate the earth instead of humans they don’t have “Ouch, I’ve been hit in the balls!” humor.
But the testicles form next to the kidneys early on in the developmental process (and as we’ve established, you don’t fuck with those stages), so they have to migrate south VERY late in the development! Because they SCHLOOP on down after everything else is pretty much in place, it weakens the abdominal wall, which is why men are more prone to certain types of hernias than women are.
Nature hires a million devs and then kills the project if they do not hit a deadline.Nature mixes it up with sex and creatures hunting one another. There are no chill moments.
There are many crabs because of convergent evolution, in this analogy that has nothing to do with refactoring. That is more similar to competing products having a lot of the same features.
If it didn't fulfil a function, then random mutations and deletions during Meiosis would quite quickly get rid of it. Even if it only serves to support the structure of chromosomes or some similarly arcane purpose that we will only discover in a decade or so, it still has a function.
Yes, the genome-layer is nondeterministic. But there are also more layers that are probably just as nondeterministic, adding more complexity to your view.
Other layers include: epigenome-layer, transcriptome-layer, proteome-layer
Each layer can compensate for deficiencies in another layer.
So lets say you knock out a gene in utero and it has a phenotype. But when you do the same procedure in an adult organism, there is no phenotype, although the gene should be important in an adult. It's like phenotype and genotype are two states whose correlation is dependent on many variables. In this example at least time.
It needs to be done at the embryonic stage before cell division so that as the cells replicate, they inherit the desired changes. The technology isn't quite there yet to transfect every single cell in an adult body with a virus containing the desired genetic modifications. Also, I can only imagine the downstream of effects of the body transcribing this modified dna in a fully-developed human. Have you ever seen the movie The Fly?
Ah, I see. I meant monkeys. (and learned the difference, german does not really have a word for ape and I always believed monkey and ape are similar words).
Probably good that we lost them. Judging by photos [1] of some of the rare cases of humans who were born with tails human tails wouldn't be aesthetically pleasing. Although perhaps human tails that are the result of something going awry might not be a good indicator of what human tails would be like if we had kept them.
If we'd never lost tails, probably we wouldn't find then so "un-human". Also, presumably most people would have "normal" (as in, the same as most others) tails, rather than like the images in that article.
That sounds like an opportunity for a whole industry to emerge tbh.
Hi we are Tailstyle! For far too long we’ve been accepting that our tails need to be naked like the rest of our bodies. Today I am offering you a share in our company for a very good price. Sharks, listen, everyone knows that wigs and toupees are amazing. What if I told you that my company we can put semi-permanent hair on your tail to look like a tiger! Or a panther? Or you could even have your tail look like that big flying dog in that one movie from the 80s you know which one I mean.
And not only that. We’re also making tail socks that you can wear for special occasions! Christmas tail socks. Wedding tail socks. Funeral tail socks. Homecoming ball tail socks. You name it!
Yeah but those guys would probably pivot to making lizard tails for the people. That’s respectable too. I just think the demand for fur-covered tails is a bigger potential market.
I'm not sure that would be as much of a problem as one might think, considering that many if not a majority of males today do just fine with their faces covered in pubes.
"The parietal eye is found in the tuatara, most lizards, frogs, salamanders, certain bony fish, sharks, and lampreys...It is absent in mammals, but was present in their closest extinct relatives, the therapsids"
Wings are so fascinating. Flying animals have their whole body, from their brain, digestive system, down to their bones internal structure and function [0] optimized for flight. That's where we see species giving up flight ability to get a stronger body, and I wonder what it would take for us to do the reverse to be able to use these wings in any way.
We'd definitely have to give up long gestation and with that, live birth, and probably a good amount of cranial capacity due to weight and energy budget tradeoffs.
Bats do not have the cranial size of humans; that's kind of the point. They may have a loosely comparable cranium to body mass proportion, but allometric mass scaling matters with respect to physiological adaptation, quite a lot[0].
The actual article in Nature points out that there have been independent tail-loss events in non-hominoid monkeys. Which makes it all the more frustrating that gibbons aren't mentioned anywhere. Given when they identify the mutation as having occurred, we can tentatively conclude that gibbons lack a tail for the same reason other apes do: 25 million years for the mutation, and 16.8 million years for the divergence of gibbons from the great apes.
So I’m guessing this is less like, “we found the flag that toggles tail production” and more “we found a chunk of code that belongs to tail production”?
The first bit of the article sure makes it sound like this DNA is what does it all.
The scientists believed that the extra AluY element was functionally working to block out a part the TBXT gene (exon6). In their mouse model, they first directly snipped out exon6, and found that mice that were heterogeneous wildtype TBXT and exon6 removed TBXT developed a full spectrum of tail phenotypes from no tail to full length tail. At this point, the statement is "These results provide further evidence that the presence of TBXTΔexon6 is sufficient to induce tail loss".
They then tried to "more realistically" replicate the scenario. Instead of just snipping out exon6, they tried inserting in various elements into the mouse TBXT gene to emulate their model of how AluY is cutting out exon6. They attempted a few different methods which resulted in different models that would end up with different relative amounts of TBXT missing exon6 being produced. I'm having a hard time tracking all their conditions and lines at this point, but they seem to claim here that higher amounts of exon6 drop out correspond to shorter tails.
They also found that they could not get any viable mice with exon6 snipped from both copies of TBXT.
TBXT itself is a transcription factor, meaning that it controls the expression of other genes. There's probably a set of genes elsewhere that together make up the "tail-making machinery" that TBXT heavily interacts with. In this sense, TBXT 'might' be the most important single point lever, but at the same time not be fully in control of the underlying machine.
What does seem persuasive is that idea that this mutation kicked off some rate of tail lose in our ancestors, which then lead to some sort of selection advantage. The advantage was then made more durable by accumulating additional mutations to lock in the phenotype. In addition, once the "tail making machinery" is inactive, we have no idea how those genes might have been repurposed. I think it's in this sense that the scientists say that we probably can't bring tails back just by "fixing TBXT".
We found the flag that toggled tail production, but the tail production code is no longer in the codebase so turning on the flag again wouldn't do anything anymore.
The code might still be there, but there are no tests for it, there have been millions of years of spaghetti code refactoring in between, and there aren't even any checksums on the storage to verify data integrity.
I have always lamented the loss of the tail. Every time my dog, though almost entirely asleep, wags its tail to acknowledge my presence, I always say to myself "Now, THAT is efficiency."
I'm not a furry, but I'm open to the possibility of getting that back!
My favorite "Scan Scene" from The Congress (Ari Folman's film based on Stanislaw Lem's novel "The Futurological Congress"), in which Harvey Keitel's character "Al" tells Robin Wright's character "Robin" the twisted tail of "Joey Fairytail"...
"The Congress" is to "The Futurological Congress" is to Stanislaw Lem like "Blade Runner" is to "Do Androids Dream of Electric Sheep" is to Philip K Dick.
Both great movies loosely based on both great but very different books by great authors, each with something unique and deep and important to say, that all stand on their own and are worth knowing.
Hair is much worse in that regard, as the tail would be positioned too low to practically grab (it would asking for a knee to the face or punches to the back of the head or spine if you tried). I think the driver is more likely to be bipedality. A tail doesn't provide a lot of benefit for balance or rearside whisker utility when moving on two legs, and would interfere with sitting and lying postures. I think humans are probably too large for practical prehensile tails too.
>and would interfere with sitting and lying postures.
I think that assumes that a hypothetical modern human tail would still be attached to the spine. A tail structure attached to the main body only through soft tissues could be flexible enough at the root to not be an issue.
I imagine it would involve taking the one that is connected and evolving one that isn't (slow selection for a smaller connecting vertebra until it becomes vestigial). Floating bones aren't uncommon (you have one in your neck); the real wrench is that it's usually for entirely vestigial limbs, not vestigial portions of functional limbs. But I'm sure life could uh find a way.
I think it would be hard because without breaking the spinal cord. Floating "side" bones are possible, but I don't know any case where the spine has been split. The spine is too central to early devdelopment to mess with it without causing chaos in later steps of development.
The problem might be size, lots of smaller primates have tails which can be very useful as a fifth arm for holding onto branches. As you get larger, tree foraging becomes less viable and the tail less useful and it would need to be oversized to be able to function properly.
Most animals are less dexterous than primates anyway. Humans talk about needing (or name products) a third arm/hand; small monkeys and lemurs and the like swing from them or use like you might imagine we would as an extra limb in climbing.
A leg has rigidity due to its endoskeleton, as well as strong muscles with good leverage, which when conditions are right gives it insane strength as it can act as a mechanical lever.
Since a tail does not have a rigid endoskeleton, it can not act well as a lever. It's functionally a rope attached to your butt. Like even if you go full kangaroo mode and make the tail more muscular than the legs, making the tail rigid by flexing really hard, it basically turns into an inefficient leg with enormous mechanical disadvantages.
But the lack of ridigity also means that it's actually quite hard to control someone through it.
If you grab someone's leg, especially near the foot/ankle, you are relying on the rigidity of the joints to be able to control their torso (and therefore their ability to fight back). The most disadvantageous position to be in is to have someone behind you, while they fully control your ankle/foot. Now you can't fully turn your body to face your opponent.
For a sufficiently flexible tail, that would not be the case. Some could be behind you and control your tail near the tip, and you could still fully turn into your attacker with your torso.
This isn't to say that a tail can't become a liability.
On the ground is perfect for kicking them in the nuts, leg/torso strikes, sweeping their legs, or various control locks. It's a near ideal place to be to also get your opponent on the ground. You can also get a solid kick or sweep in, or throw them off balance on the way down too, if you're ready for it.
The legs are the strongest part of a human, the arms don't compare at all. And fighting from the ground can be VERY effective if you know what you're doing. Or don't just curl up and wait to die.
Ideally you'd be on your feet and able to move faster of course, and I wouldn't recommend against an opponent with a spear or other ranged weapon - but then they wouldn't be trying to grab my foot or leg anyway eh?
Right, but if we're seriously talking about the liabilities that having a tail has in a fight, then presumably most of the scenarios would involve attacking from behind. Remember also that this would be mostly quadraped animals too. Legs would have been strong, but likely still arboreally adapted, so a relatively strong upper body as well.
In such a scenario, you'd probably attack from behind from a bit of an angle to force strikes from the other leg to be severely cross body.
My original point was not that attacking the leg was easy, my point is that a flexible tail doesn't give you much leverage and control and may not be as much of a liability as you think, since if you could access the tail anyways, you probably also had their back.
It's always a race to get the critical hit or lock in.
But unless the 'grabee' doesn't do anything, someone grabbing one foot from someone is likely using both hands (and most of their upper body) to attempt to control it - and there is a second foot/leg out there free to cause a lot of damage if they're willing.
It's not a 'one and done'/'game over' scenario by any stretch of the imagination if the party is even a little motivated.
Though I suspect most folks in this thread have no exposure to an actual fight beyond watching a video somewhere, so....
Coming from a stand-up striking Muay Thai perspective the only low risk way to grab a leg is intercepting a kick. You are then out of range of their upper body attacks and have total leverage physically and tactically. At that point unless the fighter whose leg is grabbed is extremely experienced in keeping a one foot balance by avoiding sweeps (ignoring the fact that one can bring the fight to the ground in MMA or BJJ etc - which imo is not preferable in a street fight) they're in a supremely disadvantaged position and at the will of the grabber. In a tournament, though, these situations usually resolve very quickly one way way or the other.
With your background. Can you extrapolate on how a tail would impact you? Would it be a big negative to have something that can be grabbed.
Also. Chimps/Primates. Don't they fight more in packs.
So if the competition was 5 on 1, would the tail become an even greater disadvantage. It would be even harder to maneuver or run, become someone could grab the tail.
I have two separate thoughts on the matter. One is whether a tail would provide me with additional balance and/or striking power. Potentially as a counterweight during round housed kicks or spinning back kicks. The second is that a tail by itself would be an inferior weapon to punches, elbows, knees, and kicks due to its relative fragility and potentially high nerve density.
So this leads to a utilitarian equation - is the additional counterbalance going to provide a sufficient edge to override the risk it adds of a relatively weak limb that can be grabbed?
As long as we're inventing limbs, why not put spikes at the end of the tail, like a stegosaurus' thagomizer. I bet that would be pretty fun to fight with.
Having done muay thai for several years - this is why muay thai doesn’t do well in less regulated environments, like MMA or actual street fights.
Because muay thai has a very structured set of rules and an environment which constrains it so that is the case. much less so than western boxing obviously, but the issue is even more obvious there.
generally still way better than no training of course.
BJJ folks consistently beat Muay Thai competitors in MMA for this reason.
being able to do both, plus some krav maga strikes? even better! though most krav maga if done with full earnestness would get you thrown in jail outside of a legit self defense scenario.
I agree with the octagon scenario, but not with a streetfight. If you're outnumbered, it is not advisable to go to ground. That is when rapid high damage strikes and the ability to dodge, block, or soak hits make you not just a physical weapon but psychological.
By the way, in full traditional muay thai, both quick and prolonged stand-up grappling is trained for.
I never said it was a good idea to go to ground in a street fight - but if you end up there (very possible!), Muay Thai isn’t going to help you technique wise. Conditioning would of course.
BJJ is as often about transitioning to and from, and controlling on the ground fighting - so having both would be pretty solid ‘academically’ probably.
It’s not like if you get jumped in a dark alley by someone they’ll just back off and let you get up if you fall down. Unless they were really stupid anyway.
Same with broken bottles, random street junk used as weapons, knives, multiple opponents, etc.
Which neither are going to teach you much about practically in real life, but better than nothing.
I think I forgot to mention how the best way to win a fight is to not get in one? Haha.
There are also a large number of banned moves in MMA. Nothing is perfect. Grabbing someones foot/leg isn't a one and done deal, either way, because we do actually have two and they're pretty powerful.
The tail seems like vestigial anatomy (originally useful in fish) that has three possible states in mammals: 1. Repurposed for a new function (tree swinging, signals) 2. Not much used but still in the repo (mice) 3. Garbage collected (apes).
I'm curious about the "garbage collected" theory as there doesn't seem like a lot of selection pressure to remove tails simply due to them not being useful and consuming energy to grow. The appendix is a far more likely candidate for garbage collection as it has no obvious function and can easily cause death if it bursts.
I suspect that there's another reason that apes lost their tails - most likely related to walking on two feet.
Yeah, I suspect a lot more people have experienced diarrhea than appendicitis. If preserving gut bacteria is important enough, then the appendix clearly does have a function.
But it might not be that important at all; do people with an appendectomy struggle more to recover from diarrhea?
Be careful with assuming functionlessness, in general. Evolution does not like spending energy on sticky-out bits that are prone to injury, or good handles for predators to catch, unless they provide some serious advantage.
Presumably as primates got bigger, tails were less useful (not strong enough to be prehensile appendages, and not as handy for balance if you climb methodically instead of carefree leaping).
Just give it a few years and besides pointed ears this will be doable. Anyways, I was thinking about whether our ancestors also wagged their tails, just like dogs and cats use them. And what were the triggers inside our nervous system.
If we're doing germline edits, the obvious thing to fix first is vitamin synthesis. There are a bunch of useful things other living things synthesise from first principles, and we don't so we need to eat something that has already synthesised the thing we wanted, and we can't cook or preserve it in any way that destroys the material we needed or it won't work. That's what scurvy is, a tree or a lizard just makes its own vitamin C, but humans don't, so, if you're stuck on a ship eating preserved food for months your body runs out of vitamin C and you get very sick and eventually die. But synthesising vitamin C isn't hard per se, it's just that the synthesis instructions can be deleted and the humans are descended from an ancestor who had such a deletion, we can put it back.
Once vitamin synthesis is back working, next up is amino acid synthesis. Amino acids are the constituent parts of proteins, your DNA is a bunch of instructions to fasten together a series of 22 different coded amino acids to make proteins. When you eat something, any proteins are broken back down into amino acids. Given some amino acids you can in principle make the others, but humans only make about half of them this way. As a result if your protein mix is wrong you are eating amino acids, and your body needs amino acids but some of them are different amino acids - and instead of synthesising the ones needed from spares you don't need using energy, which is abundant in most human societies, you just get sick and eventually (if you don't fix your diet) die. We should fix that.
I'm surprised how the conversation shifted from genetics to unethical germline editing of things that barely have clinical relevance. The rates of scurvy in the 21th century are low and definitely don't warrant super invasive editing germline cells (!), changes which become hereditary. Adding vitamin synethesis is super complex: it's not just a single SNP change but would require a whole new enzyme system. It's a very fine line from opening up a big old can of eugenics worms. Adding extra tRNAs is sometimes done in microbiology but any health benefits are extremely questionable. I've never before seen germline editing be a proposed 'solution' to malnutrition.
Vitamin synthesis is one of the most pointless things to add because it is something that is lost in many lineages over evolutionary time. The reason is that as long as there are environmental sources of a molecule the pressure to retain the ability to synthesize that molecule natively is zero or even negative, because the synthesis pathways for some of those molecules are quite nasty. You could do it, but those people would probably have increased cancer rates due to running nasty biochemistry in their own cells and eventually their descendants would lose the ability the synthesize it again because vitamin C is naturally present in their environment unless they are e.g. British sailors stuck on a boat for months with a evolutionary strange diet.
The main issue is that evolutionary pressures have optimized for and against certain things that have fragile interplay of consequences with other genes.
While it will become possible to restore auto-synthesis functionality, there are unknown risks associated with germ line edits reengineering Vit C or essential AA synthesis.
It's currently illegal to do so in 70 countries. Specific, very positive beneficial edits that protect against infections, malnutrition, or pathological diseases should be allowed.
I mean, do you want Zootopia, or do you want that weird (strangely enjoyable) Jamie Foxx Netflix movie? Because one might be mundane, but at least you don't have to worry about some guy blowing you across the block with his shrimp powers.
Like that might be a bit problematic due to the existing ears but whatever - like, if designed well you might as well have an extra pair of fluffy cat/dog/fox ears and use it for improved echolocation. ;-)
Makes you wonder why we naturally selected for ancestors who didn't have the vitamin synthesis machinery. Clearly there must have been some evolutionary disadvantage associated with vitamin synthesis, or else as you say it's clear benefits should have conferred an evolutionary advantage and still be with us today.
Not necessarily. If any early human diet that produced enough calories for them to live and procreate also happened to have plenty of vitamins, then synthesizing your own really didn't confer any evolutionary advantage.
I'd also note I don't see any reason we'd want to synthesize our own vitamins now. It's virtually impossible to get a vitamin deficiency unless you try to eat a very restrictive diet for some other reason.
There was little selection selecting against the loss it when it was abundant in out ancestors diet at that particular time and place. so by the time it became an issue it was already missing from the gene pool and as it is easier for a mutaion to break a gene than it is to gain function so its unlikely to mutate back into the genome by chance.
If we are on this topic then we need to discuss a genetically modified gut microbiota. We do not need to edit genetically ourselves for some pityful vitamins. Microbiota could give us all we want. It could enable us to digest plastic, so we could eat food without removing its packaging. We could reduce severity of our waste problems by digesting plastic into relatively harmless poop.
Actually, considering how low the birth rates in developed countries are, humans would probably (very slowly) become less and less suitable for modern life.
I would hope that phones would not remain the last point in the evolution of a personal computing device in so far as to make it able to steer the evolution of humans.
>You probably need at least 7-9 generations to select "strong pinky shelf" as desirable
It not only has to be convenient, but also to be sexually selected (partners with that seen as more attractive) or helping with survivability (partners with that live longer and get to reproduce more), which ain't really applicable anyway.
Which is the reason we don't have traits for any other minor "convenience" attribute either, but instead for long standing evolutionary benefits.
Surely it's more to do with the chances of raising viable offspring. A change that makes a person more desirable to the opposite sex is very likely to be selected for even if it makes the person more likely to die in their 50s.
Don't blue eyes support the "sexual selection" over "life or death" view of evolution though? Blue eyes don't provide any benefits to the owner other than possible sexual selection and surprisingly, they evolved before fair skin (which does provide a benefit for people in northern latitudes to produce enough vitamin D).
>Don't blue eyes support the "sexual selection" over "life or death" view of evolution though?
Is it a choice? Evolution has both "life and death" and "sexual selection" aspects.
And "sexual selection" itself is tied to "life and death" - it just concerns the life and death (or rather: existence or non-existence) of the offspring and not the person.
So, in any case, it has to be big enough to affect whether the person gets an advantage in living more themselves, or gets an advantage for having children come to life.
I'd even generalize it to 'it's about passing on ones genes'.
Death before one has had a chance to do so (or before any necessary utility towards one's offspring has passed) is evolutionarily 'bad'.
Things that help reproduction and success for one's offspring? Evolutionarily 'good'.
The tricky part is that a large portion of ANY human population is, near as I can tell, 'excess'/'hedging' population, and so will be 'doing poorly' in any given set of circumstances. Think of it as 'build time attribute randomization' when there is a random situation picked that people couldn't predict in advance.
That means that population wide, when circumstances change, the portion that is doing poorly vs doing very well can shift appropriately so the overall population survives. It is quite expensive, but seems necessary for us to have survived so long overall with the sheer number of apocalypses we know of (from plagues to invading armies), and the undoubtably countless ones we have forgotten.
Even in case something helps with survivability, the benefit must be strong enough to be selected for. Even today people are dying because of appendicitis, can't imagine the death rate in the pre-modern era.
And they're unhygenic. Sheep farmers for instance routinely cut the tails of their flock because it is difficult to shear and becomes a breeding ground for blowfly larvae. That said, i saw a movie called Shallow Hal(2001) which had a scene in which a man was shown to have a tail. Now it may have been cgi, but it made me think that there must be a minority of humans with that mutation.
There is no "why" -- it happened and was not selected against; it may have been adaptive and that is a kind of why, I guess. I think it would be better to be clear about this in science communication.
Of course there is a why. It happend and not only was it not selected against, presence of a tail was selected against. Meaning it was, or came along with a beneficial adaptation. That benefit is why it took over our gene pool and why we don't have tails now.
So they hired radicals to genetically engineer a retrovirus, to remove the tail. This worked, but due to unconsidered balance issues, all tail devoid children lost the capability for bipedal balance and therefore walking.
Most of these children, during their formative years spent their time on all fours, and thud their hand dexterity was pitiful, and society crumbled when they came of age.
It was another 46k years before a brain mutation emerged, re-enabling bipedal balance, but by that time all traces of the old civilization was lost, and thus, progress began anew.