Mouth Sets Healing Standard | Hacker News Reader

Mouth Sets Healing Standard

scientificamerican.com

30 pointsdraenei13 comments

Or, in my case, a small scratch from my toothbrush flares up into a super painful canker sore.

Don't suffer from this myself but I saw a reddit thread on this recently. It seems that SLS-free toothpaste is helpful for many people. Some other tips in there too. May be helpful for you.

https://old.reddit.com/r/LifeProTips/comments/8zadwn/lpt_if_...

> Morasso and her colleagues also tested this idea by genetically engineering mice to have more of those factors, the 'directors', in their regular skin tissue—and sure enough, those mice had significantly faster skin wound healing than did control mice.

Okay, what is the downside? I suppose there should be one, otherwise evolution would have generated mice with faster-healing skin.

Generally, the downside of having tissues grow / heal faster is increased growth rate of cancers. I'm speculating, but exposure of the skin to the sun's ultraviolet radiation may have helped determine the trade-off.

Also, I would argue that there isn't a large selective pressure for skin to heal faster. Once a wound has scabbed over, the risk of infection is relatively low.

It occurs to me that letting the wound scab over first would also protect fast replicating cells from UV radiation.

> evolution would have generated

Evolution isn't a guided process. Its just random mutations which occasionally workout preferably. Its like rolling a billion sided die a bunch of times and thinking you should have rolled a 7 by now.

Yeah, but you can say that of a lot of things. For example, the air molecules in the room are not guaranteed to spread out evenly, and at some point may concentrate near the corners. That doesn't mean we should be wearing space-suits all the time to avoid decompression.

I think its pretty obvious that evolution has not created perfect beings. Our backs, for example are still poorly adjusted to our bipedal lifestyle. whales still have legs, a Babirusas tusks can grow into its skull.

Randomly mutating genes until you get a string of successful ones is significantly harder and less likely than air molecules happening to clump up.

Edit: The litmus test for a mutation sticking is not that it improves on something, but that it does not lower the chance of survival. There are a massive amount of possible mutations that don't decrease survival chance. For example hair color. Would a green-haired human really have an evolutionary disadvantage?

Why are you arguing against claims no one has made here? No one said evolution is “guided”. No one said the current creatures which exist are in any way perfect. You’re having a pedantic argument against straw men.

amelius asked why all of our skin does not heal like our mouth. Stating there should be some evolutionary disadvantage "otherwise evolution would have generated mice with faster-healing skin". Evolution does not have some kind of internal bias towards applying past positive mutations in other places, and random mutations are not exhaustive. We have no reason to suspect that a "mouth skin everywhere" mutation has already happened and did not work out.

Guided is perhaps not the right term, "goal-directed" being a better one.

A guess, energy cost. Humans have broken free from calorie limitations. That isn't true in general for animals. Success in genetics is surviving until reproduction.

> But we can't genetically engineer humans.

But we can; it is just an opinion that we should not.

At least with CRISPR, they're discovering unfortunate side effects and unintended mutations: https://www.google.com/search?q=crispr+side+effects

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