Title says it all. Wikipedia says that it has been artificially created in mice in the lab, but that’s not what I’m talking about.
Obviously, many Downs babies in the animal world would not live very long in the wild, but I would think that with all the monkeys and apes* that have been in captivity, that some would have bee observed with that syndrome it occurs naturally.
Is there any reason that this would be a uniquely human genetic problem?
*to pick some species closely related to us
I am unsure how you would be able to assess this in a non-human animal.
Anecdotal only but I have spent a great deal of time around dogs. I have witnessed some dogs that I would consider mentally retarded (as compared to other dogs). I mean that literally. There was no formal testing, no particular measure applied except my experience with other dogs but the impression of some retardation was distinct. Not Down’s Syndrome in particular…not sure how I would spot that in a dog. More a general, “That dog’s retarded” sort of thing.
Given that we support the dogs they are quite capable of surviving and living a long life and being dogs not much was required of them beyond being friendly and cute. In the wild I am pretty sure such a dog would not last long.
Given we are all mammals (with mammalian brains to go with that) I would guess we can all suffer the same defects. Wouldn’t surprise me at least.
That’s why I mentioned other primates in the OP. Monkeys and apes look enough like us that a Down Syndrome individual should be visually recognizeable, and DNA testing could confirm it.
In fact, since Downs has a neotonous effect, it would make a non-human primate look even more unlike the adult form than an affected human does.
Well you are restricted to species that have homologous chromosomes in order to have a comparable trisomy. The Great Apes have 24 pairs compared to our 23 (because we have two fused into one) but they do have a homologous chromosome 21 and a Down Syndrome like chimp with such a trisomy was described in 1969. From the linked pdf:
That region does seem to be conserved among the Great Apes. The mouse model you reference was creating a trisomy of the chromosome that contains homologous genes in the mouse.
I am sure that trisomies occur in the wild and some are even born, but I doubt that may survive for long.
Hmm…thinking on this Down’s Syndrome is a chromosomal disorder. Different animals have a different number of chromosomes in a different order.
A human has 46 chromosomes and a dog (as an example) has 78. Apes have 48. (cite)
I would presume then a chromosomal disorder on a given chromosome in humans will not be seen in other mammals. Or rather, the effects of a chromosomal disorder will be different.
Like Allie’s simple dog?
Ha!
Yeah.
I love the one where they were moving.
More about the simple dog - moving house. I love Allie. Love her.
My cat is, well, I don’t know if you could say necessarily mentally retarded, but pretty damned stupid compared to other cats I’ve owned or known. Also she’s the only one of her 5 siblings that survived, and that’s only because we kept her inside most of the time. All of the rest died due to accidents, making me think the entire litter was retarded.
I have seen puppies which had something similar, but of course there’s no way to determine. One of the key characteristics is a small tongue and feeding problems, which I’ve seen many times in “runts” who also had roundish faces and different eyelid folds.
The genetics are obviously much different, so I don’t think you could call Downs proper, just Downs-like.
Good points, but don’t let the different number of chromosomes confuse you, though. You’ll find that all mammals are pretty closely related, genetically, and although the genes might be mixed up differently, they are still mostly the same.
But for any mammal with our Chromosome 21 fused onto another chromosome, a trisomy of that chromosome would probably produce some other disorder, or it might just be fatal. The larger the chromosome, the more like a trisomy of it will being fatal. Our chromosome 21 is one of the smallest (the higher the number, the smaller the size), which is probably why Downs Syndrome (trisomy 21) is not always fatal.
DSeid: Interesting find. I felt sure there must be some “Downs Syndrome” chimps out there somewhere.
Same way we do in humans… chromosome testing.
A cite for trisomy 18 in bonobos:
http://placentation.ucsd.edu/bono.html
The face is very different from a normal bonobo baby
http://www.bonobos.com/blog/news/exclusive-interview-with-bonobo-expert-sue-savage-rumbaugh/
Of course, trisomy 18 in humans is not the same as Down’s Syndrome (trisomy 21), but the above is to note that trisomies HAVE been observed in animals.
In general, a trisomy in humans is disabling enough that it’s either not survivable at all, or survivable only with extra support that your average animal species would be unlikely to provide.