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Scientists have traced human tail loss to a short sequence of genetic code

cnn.com

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Re: Scientists have traced human tail loss to a short sequence of genetic code

#91

Post by tsimionescu »

canadiantim wrote: post #87
tialaramex wrote: post #69

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…

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.

Re: Scientists have traced human tail loss to a short sequence of genetic code

#92

Post by smegger001 »

canadiantim wrote: post #87
tialaramex wrote: post #69

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…

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.

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.

Re: Scientists have traced human tail loss to a short sequence of genetic code

#93

Post by tgbugs »

tialaramex wrote: post #69

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…

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.

Re: Scientists have traced human tail loss to a short sequence of genetic code

#94

Post by LorenzoGood »

lazide wrote: post #90
LorenzoGood wrote: post #84

Earlier quoted context omitted.

Although when striking is involved, leg locks loose much of their effectiveness.

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 l…

For me the main example of leg locks failing in MMA is Ilia Toporia's knockout of Ryan Hall in the UFC.

Also, many powerful leg locks entries fail to succeed in MMA, due to overcommitment of limbs.

Re: Scientists have traced human tail loss to a short sequence of genetic code

#95

Post by [deleted] »

tialaramex wrote: post #69

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…

[deleted]

Re: Scientists have traced human tail loss to a short sequence of genetic code

#96

Post by Gibbon1 »

guerrilla wrote: post #86
ginko wrote: post #32

Why does the article mainly focus on the great apes? All apes, including gibbons lost their tails.

I feel like people don't focus on gibbons enough in general. It's all great apes and monkeys all the time.

I agree with this 100 percent

Re: Scientists have traced human tail loss to a short sequence of genetic code

#97

Post by Ovah »

tialaramex wrote: post #69

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…

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.

Re: Scientists have traced human tail loss to a short sequence of genetic code

#98

Post by lazide »

LorenzoGood wrote: post #94
lazide wrote: post #90

Earlier quoted context omitted.

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 l…

For me the main example of leg locks failing in MMA is Ilia Toporia's knockout of Ryan Hall in the UFC. Also, many powerful leg locks entries fail to succeed in MMA, due to overcommitment of limbs.

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.

Re: Scientists have traced human tail loss to a short sequence of genetic code

#99

Post by datameta »

lazide wrote: post #90
LorenzoGood wrote: post #84

Earlier quoted context omitted.

Although when striking is involved, leg locks loose much of their effectiveness.

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 l…

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.

Re: Scientists have traced human tail loss to a short sequence of genetic code

#100

Post by icegreentea2 »

lazide wrote: post #79
kjkjadksj wrote: post #74

Earlier quoted context omitted.

You can’t land a kick when someone has your foot. Gravity exists, you will immediately fall onto your butt as soon as you lift the other leg.

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. You might find BJJ pretty interesting. [ https://renzogracieacademy.com/about/what-is-brazilian-jiu-j... ], [ http…

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.

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