George Church

Without...

going all the way back to the embryo and forward again.

And there's various other things that are just short of that.

If you replace the cells, well, they'll fit into that niche.

They might displace the old cells.

You know, that's...

certainly within the realm of modern synthetic biology is for cells to take over niches.

I think the hardest part is brain, but even there, there's some evidence that if you bring, even though the brain doesn't really use stem cells that much, you could artificially bring in stem cells and they could artificially fit into a circuit and learn the circuit and then displace the old ones in some way.

Yeah, exactly.

Ship of Theseus.

Having, you know, trying to maintain the connections and the memories.

But, you know, there's some fairly straightforward experiments that need to be done before we can really even estimate how hard that problem is.

Or, you know, very often there's low-hanging fruit that people just...

think is improbable but it's there because biology has all these gifts that you know where the uh just hands over to us uh levers that we can flip like like vaccines this amazing gift that didn't have to exist but they they do yeah

There is nothing close to that today, but there's nothing, no law of physics that would prevent it.

There's going to be practical considerations like

You know, how many injections do you need to do to achieve that goal?

But we're getting better at targeting tissues.

You know, so for one of my companies, Dino Therapeutics, showed they could get a hundredfold improvement in targeting neurons in the brain, which is a big deal.

Now, if...