[ExI] interesting new NOVA episodes

Kelly Anderson kellycoinguy at gmail.com
Mon Jan 31 17:34:54 UTC 2011


2011/1/29 Dave Sill <sparge at gmail.com>:
> Speaking of NOVA, did anyone catch "Dogs Decoded"? I thought the whole thing
> was fascinating, but two things especially interesting.

I really enjoyed that episode as well.

> One was an
> experiment in which people raised first puppies then wolf cubs. Dogs and
> wolves are genetically identical, but as the cubs grew up they didn't bond
> with their people and acted like wild animals.

Dogs and wolves are genetically similar. If they were identical, they
would be clones. What is fair to say is that they are for all
practical purposes, still the same species, since they can interbreed.
On that basis, it would seem that since there is evidence that humans
and Neanderthals interbred, that Neanderthals are "identical" to
humans, which I don't think anyone here would agree with.

The key I got out of the show wasn't so much that the wolf cubs didn't
"bond" with their humans, but rather that they were not able to pick
up on the subtle cues that the humans put out and were thus unable to
learn proper behavior effectively. Puppies outperformed great apes in
responding to pointing and facial cues. So somewhere in the genetic
mixing, dogs obtained a mechanism for reading human faces and gestures
that is unique to dogs. Wolves don't have that. Other primates don't
have that. Only dogs. Very interesting stuff.

> The second was the Russian
> experiment to domesticate silver foxes by selective breeding. They've been
> doing it for 50 years and have bred both a calmer strain and a
> more aggressive-to-humans one. Again, they're all genetically "the same",

Meaning only that they have not created a new species. The amount of
Serotonin in the brains of the two groups is off the charts different,
and that likely comes from the difference in genetics between the two
groups. I would guess that the amount of Serotonin has something to do
with the expression of the genes that make floppy ears, tail changes,
different coloration of hair and so forth.

> but when they have a tame mother raise an aggressive cub, it doesn't calm
> down at all. They've also found that as the calm strain becomes more
> domesticated, it gets more and more dog-like: shorter tail, curly tail,
> white markings, etc.

This wasn't in the show... but I heard from other (unverified) sources
that the original intention of the breeders who began this program was
to create foxes that were easier to handle for fur raising. They were
very disappointed when it didn't work out (the colored fur was not
acceptable for making fox fur coats) and I think at that point the
scientists took over because of the interesting results.

> It seems like a likely explanation for these two cases is epigenetics, but
> the NOVA episode said nothing about that.

I think there are genetic differences sufficient to explain what is
going on... it doesn't take very many gene differences to have this
sort of thing come out. Occam would probably go with gene drift over
epigenetics for most of what you're seeing. OTOH, the friendliness of
a specific animal would clearly go up with human handling. Ferrets
have to be raised with lots of human handling when they are little, or
they grow up to be completely wild. I can say from personal experience
that it is much the same with cats. I have a few cats that weren't
properly loved as kittens, and they are as wild as the outdoors.

I hope some of the foxes escape from their lab into the pet
marketplace, they are pretty darn cute.

-Kelly




More information about the extropy-chat mailing list