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The Silver Fox Experiment


Tommy Coyote
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The scientists here probably already know all about this but I thought it was really interesting.

 

A scientists bred silver foxes to see if he could domesticate them. And it worked. It took him 20 generations. But the more interesting thing was how the animals changed physically over time. He was breeding the most docile animals generation after generation.

 

The domesticated animals had shorter faces, smaller teeth, soft and droopy ears, curly tails and altered color. The domesticated foxes looked a whole lot more like domesticated dogs.

 

I read another article similar to this not too long ago where a fur breeder did the same thing and he claimed it only took 6 generations.

 

I wonder why domestication changed their physical appearances so much? Anybody know?

 

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Must just be that the genes are linked somehow- maybe on the same chromosome? So if you get one you're more likely to get the other. Or it could be that you are selecting for other things (reduced adrenaline) and those things make the physical appearance more likely to change.

 

The sad part of the Belyaev story is that Dmitri Belyaev's big brother Nikolai also worked in this area, and I believe on this project. Unfortunately the Soviets at the time were wedded to Lysenkoism (like a nonsensical gene-denying 'science' that got popular for political reasons). Genetics was, to put it mildly, not in fashion and so Nikolai got executed without trial. That's why there is now only one Belyaev who discovered the physical changes in domestication.

 

Dmitri Belyaev managed to continue his work, largely by talking about it as studies in physiology rather than genetics, and managed to last until the political atmosphere eased a bit. Fair play to all the scientists, and people of all stripes*, who managed to get through those days and did politically dangerous things for the sake of science and humanity.

 

*For example psychiatrists who would declare political dissenters 'insane'. Sounds like a bad deal for the dissenters? The psychiatrists often did so to try and help their patients avoid death or imprisonment- some of the psychiatric hospitals at least had food and an absence of beatings.

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I'm not sure what projects you're referring to, but the one many years ago in Russia or Siberia was with foxes being raised for fur.

 

In that case, what they were trying to do was to breed foxes that were easier to handle, so they selected foxes that had l the least flight distance at first, and then kept selectively breeding for foxes that were more and more friendly to humans.

 

So the selection pressure was for decreased flight response and lack of fear (then friendliness) towards humans.

 

They were very surprised -- and a bit dismayed as I recall -- to find that the physical characteristics also changed. Coat color and pattern changed so much that the foxes were no longer usable in the fur trade, though they followed their keepers around like dogs.

 

Interesting stuff, and an excellent example of how breeding for one characteristic can drastically alter others.

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Source, GentleLake? That sounded snippy, of me, sorry- I just haven't heard that version of the story before.

 

The Belyaevs were geneticists, and I had thought that Dmitri had actually predicted physical changes would occur because of a potential connection between melanin and adrenaline. They also bred hyper-aggressive foxes, and tame and aggressive rats, minks, and otters. They did things like have tame foxes raise aggressive fox kits, to see how far it was purely genetic.

 

While he was head of a fur breeding programme, he was dismissed from that position about a decade before beginning his famous experiment: at the time he was head of an institute of genetics and cytology.

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Sorry, but I don't know. I remember it from a documentary I saw on TV many years ago, but don't even remember if it was entirely about the fox experiment or just a section from a larger theme (I suspect the latter, but am really not sure).

 

Don't have time to research it now (I still need to follow up on the biotin thing LOL) but will try to see if I can find anything on it later.

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I saw that same documentary. It showed them walking down rows of wire cages. The friendlier ones looked very much like dogs with floppy ears and colored coats. I quickly found this clip below on YouTube. I wish I could remember where I originally saw it, maybe national geographic or something on Netflix.

 

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It was a closed population in that they were captive bred in a fur farming operation.

 

They said (in the documentary) that they were selected for lack of fear, but it's hard to say how the closed genetic pool may have contributed.

 

ETA: The clip provided above doesn't say anything about the foxes' pelts being unsuitable for the fur trade.

 

I know I've seen several references to this breeding project, and I may well be collapsing information from more than one source.

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My recollection of the Silver Fox genetics story is the same as Simba. Yes they did some line breeding, but the behavioural characteristics that they were selecting for was basically 'friendlier/more domesticated;'

 

ETA - oh I've just seen that while I was writing this post that waffles posted a link to a review article on the work..thanks for this

 

Another interesting bit of work on how dogs evolved to communicate with humans is the family dog project in Hungary that is currently headed by Dr Adam Miklosi

http://familydogproject.elte.hu/index.html

 

there is a short National Geographic video describing some of his work

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Dear Doggers,

 

This forum is a wonderful resource.

 

This fox study is often cited as crucial evidence for the theory of neotony (ie, wolves are "tamed" into less intelligent, less resourceful but human adapted canines) by selection for retention of juvenile behaviors (willingness to learn new things, submissiveness to humans) and such juvenile taming is evident in the retention of juvenile morphological features - as with the russian foxes.

 

I believe this is nonsense, canine phrenology, but at least until recently ( today?) neotony was the accepted theory of how dogs became our useful companions.

 

Donald McCaig

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That reminded me of something. Some people down the street had a wolf or a wolf-dog. It looked like a wolf. It was the smartest dog I have ever seen. But it was a horrible pet.

 

I watched that dog one day go over the whole fence line looking for a way to get out. It checked both the top of the fence and the bottom of the fence. Went completely over the whole thing.

 

I've never seen a dog do something like that. But they couldn't keep it in the yard and eventually animal control got it. But only after hours of chasing it around the neighborhood. I had tried to get ahold of it after the owners simply gave up and turned it out. It was too shy. I couldn't get anywhere near it. Even with hotdogs.

 

They say that about wolves that you can tame them but they never can be trained. They aren't wired to communicate with humans like dogs are.

 

And one of the things they mentioned in that study was that the foxes became more and more social over time. Wild silver foxes are solitary but the domesticated ones weren't solitary any more.

 

Interesting.

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https://en.wikipedia.org/wiki/Domesticated_silver_fox

 

http://cbsu.tc.cornell.edu/ccgr/behaviour/Index.htm

 

Phrenology? No but perhaps nephrology (since it may be linked to adrenal gland function but endocrinology would be better term). Lower hormonal production likely linked to tamer behaviour. Different hormonal level also expressed genes differently, which can lead to different looks and behaviours.

 

Looking different and acting different happen simultaneously, but not yet proven if they are linked. A->B, and A->C does not necessarily mean B and C go together (but does show a correlation).

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Sorry, but I don't know. I remember it from a documentary I saw on TV many years ago, but don't even remember if it was entirely about the fox experiment or just a section from a larger theme (I suspect the latter, but am really not sure).

 

Don't have time to research it now (I still need to follow up on the biotin thing LOL) but will try to see if I can find anything on it later.

 

Was probably Nova on PBS "Dogs decoded", fox experiment starts at 36m20s or so (there are some border collies starting at 27m with a pup and then Betsy and the 300words she knows)

http://topdocumentaryfilms.com/dogs-decoded/

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https://en.wikipedia.org/wiki/Domesticated_silver_fox

 

http://cbsu.tc.cornell.edu/ccgr/behaviour/Index.htm

 

Phrenology? No but perhaps nephrology (since it may be linked to adrenal gland function but endocrinology would be better term). Lower hormonal production likely linked to tamer behaviour. Different hormonal level also expressed genes differently, which can lead to different looks and behaviours.

 

Looking different and acting different happen simultaneously, but not yet proven if they are linked. A->B, and A->C does not necessarily mean B and C go together (but does show a correlation).

Yes but CptJack posted this link on another discussion thread (about possible working talent in a dog with a large Barbie component in its pedigree)..though actually it is more relevant to this thread & also to the floppy ear discussion thread. IMO

 

The authors of this article suggest that the reason for many diverse alterations happening simultaneously may be due to alterations in neural crest cells. These are fascinating cells in the developing embryo that become a number of different structures in the animal. These include the bones of the skull, a number of hormonal glands (including the part of the adrenal gland that secretes adrenaline/epinephrine) and the melanocytes that are important for coat colour.

 

These authors hypothesise that during domestification a single gene mutation may occur to effect neural crest cell behaviour. Because this one set of embryonic cells have so many different roles during development, this single mutation could cause the apparently unrelated effects on coat colour, head and face shape and also some aspects of the altered behaviour (via alterations to the endocrine system).

 

(ETA ...and as the Merle mutation also effects neural crest cell behaviour, this may also explain why some people think that there may be subtle behavioural alterations in dogs with this coat pattern (again via alterations in the endocrine system))

 

As Mr McCaig says 'this forum is a wonderful resource!'

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From what I remember the project was started because fur farmers wanted a fox that was less aggressive. Dmitri Belyave began selecting the tamest foxes for breeding and by the 10th generation there were some major changes in appearance.

 

The foxes in the program were tested and had much lower levels of adrenaline from normal foxes. The genes responsible for adrenaline are connected to the ones responsible for melanin and that could possibly explain the change in coat color (I am not a scientist so I don't know if this is correct).

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@Maxi - I swear I could follow you around like a puppy dog and just read your posts.

 

 

Yes but CptJack posted this link on another discussion thread (about possible working talent in a dog with a large Barbie component in its pedigree)..though actually it is more relevant to this thread & also to the floppy ear discussion thread.

 

...

 

As Mr McCaig says 'this forum is a wonderful resource!'

I shall third the sentiment. It IS a wonderful resource.

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Yes but CptJack posted this link on another discussion thread (about possible working talent in a dog with a large Barbie component in its pedigree)..though actually it is more relevant to this thread & also to the floppy ear discussion thread. IMO

 

Looks like the 'neural crest hypothesis' gained a lot of traction in the popular press (eg was reported by The Economist and others) but the original paper is careful to characterize it as an interesting hypothesis that requires much more research.

 

Original paper: http://www.genetics.org/content/197/3/795.full

(see two last paragraphs of the conclusion)

 

Looks that it's at the 'that's an interesting idea' stage rather than well substantiated. I'm not ready to buy into it yet, how would it explain some dogs have pointy ears and others not, or why do some BC puppy ear sets change on a daily basis (being facetious here, it is an interesting idea but is it cause, consequence or coincidence).

 

P.S.: elephants have floppy ears ;-)

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Looks like the 'neural crest hypothesis' gained a lot of traction in the popular press (eg was reported by The Economist and others) but the original paper is careful to characterize it as an interesting hypothesis that requires much more research.

 

Original paper: http://www.genetics.org/content/197/3/795.full

(see two last paragraphs of the conclusion)

 

Looks that it's at the 'that's an interesting idea' stage rather than well substantiated. I'm not ready to buy into it yet, how would it explain some dogs have pointy ears and others not, or why do some BC puppy ear sets change on a daily basis (being facetious here, it is an interesting idea but is it cause, consequence or coincidence).

 

P.S.: elephants have floppy ears ;-)

 

@Mtnfrank

but the article CptJack originally posted the link to also states this idea needs more research. One of the main points of the conversation.com site (that is linked) is that it is a website where university academics can post articles that discuss a variety of issues..The main strength of this site is that the academics who write the articles have relevant expertise to comment..ie they are not really the 'popular press' that your post implies.

 

I did say it was only a hypothesis (ie idea/ theory/suggestion) and I only spent a bit of time explaining it because I thought neural crest cells were probably not something that a non- scientifically trained audience (of whom I presume are the majority of this forum) would necessarily have heard of.

 

The idea may not relate directly to the variety of ear positions seen in BCs (though the very fact that this is so varied means that you would almost inevtably have to hypothesise that further modying genes effecting cartilage rigidity post natallly are required in order to cause the diversity of ear position seen in the domestic dog).

 

however, it certainly is a very plausible and unifying suggestion of why face/head shape and coat colour changes are seen together

 

I also agree.that the neural crest cell (NCC) hypothesis almost certainly doesn't explain all the behavioural changes associated with domestification.

 

However If the 'NCC theory' is the cause of the coat colour/face shape changes then it is likely the effected gene for this part of the 'domestification syndrome' is located physically close to one of the 'behavioural' genes on a chromosome. This could then result in the NCC mutation 'hitch- hiking' along as the behaviour alteration is selected for by the scientists (i.e the 2 genes are 'closely linked' to use genetic parlance),

 

But yes more research is required... When is it not? (otherwise what would keep all the academc researchers employed?).

 

P.S Not really clear what the comment on elephants relates to...their ears have adapted to suit their needs.

 

ETA. You have to remember there is a difference between the original 'domestification syndrome' when dogs became 'man's best friend' (that the silver fox experiment may mimic) and any subsequent selection for any particular working/physical traits. The first relates to characteristics that distinguish all dogs from their wild ancestor, the second relates to particular breeds or even specific dogs. As working BCs are selected for their work ability.. ear position itself is not crucial (even if some prefer one particular position) . Therefore it is completely plausible to have a NCC mutation that may have caused 'floppy ears' during the initial ancestoral domestification process but then subsequent gene modifications occur later during dog evolution and it is these later alterations that determine whether ears in a particular dog stick up or flop.

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From what I remember the project was started because fur farmers wanted a fox that was less aggressive. Dmitri Belyave began selecting the tamest foxes for breeding and by the 10th generation there were some major changes in appearance.

I don't know, I mean, since he was already studying physiology plus was head of an institute in genetics, and selected tame or aggressive animals of many different undomesticated species, it seems like it was plausible to think that it was to investigate the genetics of domestication. I have heard that before, that it was about fur farmers. But because it's someone who was working in politically dangerous areas at a time when he had already had a family member killed for that reason, I am inclined to think it was more than that.

 

Especially since it has been framed (and not by you or anyone else in this thread, in any way, but when I initially started learning about it) as a 'hur hur silly Russian fur farmers' thing, which annoys me given what these guys had to face to get the basic academic work done the rest of the world was taking for granted.

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. Sorry. I'm still trying to figure out droopy ears. What is the point? Seems like prick ears make more sense. And what advantage is a shortened face?

 

Well the short answer is that they probably don't have any benefit for a wild canid... but you have to remember that short faces & droopy ears seem to appear when humans decide which 2 animals to breed together. This means that the selection pressure in this situation becomes very different than for animals that need to survive & breed in the wild.

 

The long answer has to do with genetic linkage and it is probably necessary to assume (i.e guess!) that whatever gene mutation(s) that cause(s) droopy ears & short faces is close to a gene associated with 'domesticated behaviour'. If you wish me to explain this concept in more detail (or someone else doesn't do it first), then I'll try to explain how genetic linkage works later on this evening as currently I need to do some outdoor chores while the sun shines ;)

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It's about time someone brought up Sheila Grew's classification of Border Collie working styles based on their looks. In her famous Key Dogs of the Border Collie Family she described four types based on phenotype. I found that idea fascinating when I first read it many years ago and find it so today as well.

 

Amy

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