As we are able to grow human organs in/on other animals (ear on mouse, liver in pig, etc) could we transplant the human vocal apparatus to a chimpanzee, with a view to it learning speech by imitation?
I’ve heard of the Russian dog-head transplant thing, and I’d love some transplanted cow’s stomachs to digest cellulose but these seem too complicated and would need a structural overhaul to accomplish. I would think the ‘voicebox’ would be more like a plumbing job though.
This part is only sort of true.
Ears are mostly cartilage, which aren’t generally subject to problems of tissue rejection. The ears grown in mice aren’t human organs but animal organs inserted into humans.
Pig livers aren’t actually transplantable, yet. The few trials in humans so far have involved using pig livers as temporary blood filtering apparatus. No actual transplantation.
Basically, we really can’t transplant complex animal organs into humans or grow real human organs in animals yet.
I think we’re getting close with growing corneas in pigs, but again, it’s a situation with lower chances of rejection (no blood vessels in corneas).
This doesn’t follow at all.
The transplants so far have involved close structural and physical matches (i.e. stuff that should already be there anyway) with low chances of rejection.
It’s several giant leaps to go from there to implanting structures willy-nilly into other animal and hoping they’ll work like they do in the original animal. Tissue rejection will almost certainly occur and be quite painful.
See the movie O Lucky Man.
The internet tells me the larynx has nine distinct cartilages - don’t other primates have similar structures? They already vocalise, albeit quite unimaginatvely - has your concern for animal pain coloured your science?
Speech is heavily tied into brain structures like Broca’s area. Chimps may have some analogue brain features, but their capability with sign language - while impressive for non-human language - would still be considered sub-par for a retarded human.
Even with the proper brain structures, studies on feral human children suggest that we have certain key windows of opportunity to learn language. You miss your chance when you’re a toddler and you’ll never master the language. So language is also not just an anatomical construct.
In other words: you’d need a brain transplant to go along with the organ.
This, and more so. The earliest experiments with chimpanzee language acquisition attempted to teach chimps to talk, and these projects were total failures. According to something I read (25 or so years ago), the chimp failed to speak, with symptoms that resembled aphasia, which is an inability to speak (in humans) due to certain types of brain damage. This led to the discovery that Broca’s area, although present in other primate’s brains, is poorly developed and rudimentary.
This area of the brain is specifically involved with production of speech, as opposed to understanding of language. This idea led to later experiments which attempted to teach language to chimpanzees via other media – manual sign language or manipulation of visual or tactile symbols. Those attempts showed some basic success – although the language was rudimentary, it went far beyond anything that any animal was ever expected to learn at the time.
Since then, there have been many experiments attempting to teach language to various animals. None of them ever approached the level of human language. Several of the chimp language experiments have become very famous (Washoe, Nim, Lana come to mind). Penny Patterson’s work with Koko the gorilla have been widely reported, and likewise Irene Pepperberg’s work with Alex the African grey parrot.
Other projects have been done with dolphins (Herman et al) and sea lions (Schusterman).
ETA: Invariably, the failures to learn language beyond the rudimentary has been rooted in the brain structures, rather than in the physical vocal apparatus (which, in most species, would also be a limiting factor, if brain structure wasn’t already the limiting factor).
Ahh, some abilities are tied into brain structures. This must be why my experiments into transplanting elephant trunks onto people are failing. I need to transplant the elephant’s brain, too!
You are welcome to your sarcasm, Dumbo.
No. Looks like your ignorance of biology and medicine and liking for a good fantasy has clouded your judgement. The possibilities for successful inter-species transplantation of anything, given current or foreseeable technology, are extremely limited. Furthermore, the human vocal apparatus certainly does not consist solely of cartilage. It would be rejected if transplanted into another species. Quite apart from the fact that that would cause great suffering (probably death) for the animal, it means that the transplanted organ would be destroyed.
The human FOXP2 gene is critical for the neurology of speech. People with mutations of this gene have speech development problems. Additionally, humans have a gene that reduces muscle development round the skull/jaw, which is also critical to speech.
Short answer - it isn’t just a lack of appropriate equipment that stops chimpanzees from speaking. There are a bunch of differences that allow human speech.
The larynx isn’t just the cartilage. It’s also the nerve endings, blood vessels, other connective tissue that hook into the person.
The ear ‘transplants’ were only transplants of cartilage - not of any of the stuff that actual ‘hears’. Likewise, the pig liver experiments have only been to temporarily filter blood, not as a semi-permanent replacement.
I have no idea what concern for animal pain has to do with it. Any attempt at a voicebox transplant would only be useful for seriously maiming or killing the subjects involved and wasting the organ, not to mention wasting the time and effort of the surgeons and staff.