> What % is too human to harvest for organs

I don't think it's really measurable, because a meaningful "%" implies a relatively context-free, relatively uniformly distributed importance to genetic sequence.

The most immunogenic sugar is glycolylneuraminic acid. Humans are incapable of making this sugar so it's immediately recognizable as alien by the human immune system.

You could in theory disable production of this sugar with a single base pair mutation which (if that's how you did it) would make this .000001% sequence difference extremely important over almost any other sequence point.

As a side note it's a matter of speculation that the lack of this sugar is an evasion mechanism for species-jumping flu.

Edit: tick thing was wrong, I had misremembered! Thank you smart reader who has since deleted their comment calling me out.

I don't think it is all that uncommon for regular human-to-human transplant recipients to be on immunosuppressants for life. If I'm not mistaken, that's the case for all organ recipients, but there may be exceptions. I think the concept of "immunocompatibility" can refer to a spectrum of outcomes that we haven't gotten down even for transplants within our own species.

Yes all transplant patients receive immunosuppressants. The only transplant that wouldn't would be an allogenic stem cell transplants (uses the persons own stem cells), however these people typically don't have an immune system to begin with.

They’re not making the pig more human, they’re removing the markers of ‘foreign’ that would make it an immune target. So it’s a nice vanilla organ that minimally attracts the attention of the immune system.

According to another article: https://www.usatoday.com/story/news/health/2022/01/10/human-...

> Three genes were turned off that might otherwise have triggered an immediate immune rejection – the recognition of a pig organ as coming from a different species. Six human genes were added to prevent blood from coagulating in the heart, improve molecular compatibility and reduce the risk of rejection.

> One final gene was turned off to keep the pig from growing too large.

So they actually did make the pig a tiny bit human.

imho complaining about anything that doesn't touch the brain is really pushing it

Just removing some sugars can't possibly work, since the pig heart will lack correct MHC class I molecules, which will make it a target. So the patient will need permanent immune-suppression.

Plenty of transplant recipients from deceased or living human donors are on permanent immunosuppression. Depending on the organ and the person, day-to-day life can be almost completely normal. Source: I am a liver transplant recipient.

On the other hand (and I am being flippant... Slightly) how do you know that removing this one gene doesn't unlock consciousness?

>how do you know that removing this one gene doesn't unlock consciousness?

i'm not the poster you're replying to, but for me the answer is this :

consciousness appears to me to be a constellation of traits rather than a trait itself that would be easily acquired with a genetic shift.

One could then say : 'What if the one we flip is the thing that finishes the constellation of traits that activates consciousness?' , and sadly I must confess that I believe that if that were to happen to an entity without sufficient communications methods that it would probably remain unknown and subject to whatever experiences whatever sensory organs it may have provides it, while we remain entirely unaware for some time.

Also, a point that I agree upon by the poster who replied to you with me ; we don't seem to hold conscious entities in very high regard -- only human ones.

relevant SMBC: https://www.smbc-comics.com/comic/intelligence-2

A strange idea but theoretically possible. Although it wasn't one of the genes targeted in this study, humans are the only animals which have the Neu4Ac form of the sialic acid sugar, instead of Neu5Ac, and the brain is one of the regions that is most heavily sialiated in humans and could be one of the things that sets us apart.

https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC7153325/

I mean pigs are already "conscious" on some level, I'm sure.

I'd definitely think of pigs conscious given they can play video games: https://www.bbc.com/news/technology-56023720

> how do you know that removing this one gene doesn't unlock consciousness?

The words you're looking for are sentience or even sapience.

Speaking of chimeras, there is a Greg Egan short story from his book "Axiomatic" about a human leopard chimera which is bred by an eccentric billionaire specifically to pose for a painting. The actual story is even crazier.

I think the nervous system is really the only part that I'd have ethical concerns about.

If they can grow a pig with a 99% human heart, I don't see why that should be more ethically concerning that harvesting a 100% pig heart.

The concern, I think, that it's obviously unethical to grow a 100% human child and then harvest its heart, right? You're talking about a living, feeling, thinking person! Causing them to suffer or to die is morally wrong, conversely, their life and their right to life have precious, incalculable, sacred value. The thought of harvesting, murdering a human being for one of their organs is repulsive, harvesting them for food is cannibalism and a taboo of the highest order.

And yet many humans eat bacon for breakfast without a second thought. On the operating table, the human heart and pig heart would probably be indistinguishable to a layperson, so why is the one sacred and the other free for the taking?

This is an ethical concern which is so completely removed from reality that it borders on satire. This is why no one takes bioethicists seriously anymore.

What part do you think opens that door?

Human organ recipients also need immunosuppressants forever, outside of rare cases. This particular case sounds like a very small modification to the source pig, not a pig carrying a human organ.

I mean I imagine there's research trying to do exactly that: you can identify beating heart cells very early on in embryos, and chimeric organisms are a thing. I imagine someone somewhere is trying to swap out those early cells with human heart cells to see if you can literally grow a pig with a human heart.

I think people will only accept 3d printed organs, pig and animal things are too controversial for some people.

I was listening to a podcast on the CBC about AI and consciousness, and the idea that humans are distinct from an animal (beastmachine, great name for a butcher shop btw) comes from Descartes, who we revere in philosophy (for fair reasons)..

I think we can't blame people for wanting to separate themselves from animals.