Hacker News Reader

Comment by dekhn | Hacker News Reader

I can't see any way that you could regrow a limb without "touching genes". And Levin doesn't say that in his video. At the very least, limb regrowth would require synthesis of many mRNA and their protein products, under the control of transcription factors.

View on HN

Yes, but you don't do that. The cells themselves do it. You only trigger that mechanism and you do it by opening and closing specific ion channels in specific patterns.

The article is specifically about a difference in the mTOR protein, so in the end, a genetic difference. You will not trigger a limb regrowth in humans by opening and closing specific ion channels in our cells.

> You will not trigger a limb regrowth in humans by opening and closing specific ion channels in our cells.

Levin's research begs to differ. He did successfully regrow an amputated leg in a frog.

I seem to think you're interpreting that in a way that is not consistent with our current understanding of limb regrowth.

This is the paper: https://www.science.org/doi/10.1126/sciadv.abj2164 and it clearly states they treated a frog (xenopus, a common model organism), which does not normally regenerate when it's an adult. The paper clearly states that they treated with a set of factors that they believe induced a developmental plan- implemented by the transcription of DNA, translation of RNA, and expression of proteins. The initial treatment was removed, and the effect continued.

Also there's nothing about ion channels in this- the factors they used must have been actively transported- they bind to protein receptors.

I’ve watched at least half a dozen long presentations and interviews from dr levin and I’d say the previous commenter is essentially repeating it exactly how Levin describes it. To be fair it’s not exact. What I understood from the interviews is that they have been imaging bioelectrical activity in organisms during development and claim to have deciphered patterns associated with growth of certain structures. He talks about a certain ion channel drug (one used for epilepsy I believe) which they used to reproduce the bioelectric field previously observed and the organism grew a leg. Multiple legs actually, wherever they wanted. Also working eyes on arbitrary locations.

So from a high level they say they have figured out how to “speak” to cells in a sense and instruct them to start building certain structures. And they emphasize that they aren’t making any changes to the genome or manage any of the low level processes themselves.

Unless you can point me to some succinct papers or summaries, I'm going to continue with my believe that the dog wags the tail, not the other way around.

Frogs are not humans. Amphibians do have the genetic potential for limb regrowth.

Genes encode proteins and do not contain any other information.

The celular machinery and its goals are separate from genes and can be controlled without "touching genes".

"Genes encode proteins and do not contain any other information": this is entirely false. It's well established that genes contain non-encoding regulatory regions (which happen to be very important for the process we're discusion).

All the cellular machinery ultimately derives from genetic regulation and protein expression. You can't make more of it wihtout making more mRNA, translating that to protein.

This is bio 101, basic stuff, unless I'm completely misreading what you're saying.

Reply on news.ycombinator.com