3 ms·
They buried the lede: Even if the driving mutation identified in the study could be undone, “it still wouldn’t bring back the tail.” Oh well.
by K0balt 3y ago
They buried the lede:
Even if the driving mutation identified in the study could be undone, “it still wouldn’t bring back the tail.”
Oh well.
- Waterluvian 3y agoSo 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.
- layer8 3y agoProbably the difference between necessary and sufficient.
- icegreentea2 3y agoThe 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".
- GordonS 3y agoJust wanted to say thanks for this excellent summary!
- ummonk 3y agoWe 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.
- snovv_crash 3y agoThe 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.
- GoodPepper50 3y agoSo close!
- 7thaccount 3y agoThe greatest thing on this thread is how disappointed we all are for some bizarre reason lol. It would be cool to get them back for better balance.
- sebastiennight 3y agoA prehensile tail would do so much for my cooking skills... the possibilities are infinite. Wait - I finally found a use case for Neuralink that I can cheer for!
- underlipton 3y agoYou don't necessarily even need invasive surgery to control an additional limb: https://spectrum.ieee.org/human-augmentation https://spectrum.ieee.org/human-augmentation
- GoodPepper50 3y agoExactly! And why stop at only one extra appendage?
- datavirtue 3y agoThey aren't trying hard enough,then.
- Natsu 3y agoThere are some people who are born with tails, though: https://www.webmd.com/baby/what-is-a-human-tail https://www.webmd.com/baby/what-is-a-human-tail