I was reading about the Russian fox-breeding experiment which has resulted in tame, domesticated, foxes.
This process resulted in physical changes in the animals, shorter legs, floppy ears etc
This also appears to be the case in other animals that were domesticated. What’s the reason for this?
Thanks!
As I understand it, by selective breeding for particular traits, such as ‘tameness’, they are promoting certain genes that also happen to influence physical attributes. The fact that they were able to do it so quickly is what is amazing. Think about the common wolf-like ancestor to modern dogs. By constant breeding over 10,000 years man has turned a wolf-like animal into you next door neighbor’s toy poodle.
Note that genes are not the full story. Changes in gene expression can happen much, much sooner, and as it turns out, mothers can pass on these gene expression patterns.
Gene expression changes are “temporary”, it would mean the foxes would retain the ability to revert to their “wild” phenotypes. This is almost certainly what is happening here, because selection on the level of genes is very slow, especially for changes this dramatic.
A lot of the things we’re breeding for are traits that are found more in young than in adults, so the easiest path towards those traits turns out to be to breed for youthful traits in general (this is called neoteny). So getting the juvenile psychological traits often means also getting the juvenile physical traits.
That’s what I was going to say as well- the selection process that goes on for domestication acts on a package of traits- in the case of foxes/wolves/dogs, it selects for certain behaviors and a certain degree of neoteny, since cuter animals are perceived as less threatening.
It’s like saying that if you somehow bred men for muscle mass, you’d probably have a bunch of classically masculine looking males- heavy brow ridges, chins, beards, etc… since that stuff is a result of the same things that cause more muscle mass.
Thanks for the answers everyone, that makes sense!
It’s not just about cuteness-- In fact, cuteness is probably almost entirely one of the side effects. It’s more about the young being more willing to accept an adult as an authority figure.
You can select on the basis of genetic traits very rapidly, providing that you practice rigorous selection and that the trait selected for is governed mainly by a single gene. For example, it would be easy to select for blue eyes in humans if you selected your breeding population from only blue-eyed individuals. The offspring would be 100% blue-eyed.
I used to train and breed English pointers and setters for field trials. I was always amazed at the skill some of the breeders had when it came to recognizing very specific physical and behavioral traits that would accurately predict a dogs behavior as a field trail bird dog and breeder. Not unusual to see dogs that could hardly qualify as a pet any more than a tamed wolf or any other wild animal. Changes in the teeth, ears, jaw set etc have also been reported by experts in the field. They are often accused of cross breeding but some of the ones I knew did not find that neccessary.
And that might connect with the “dangerous dogs” argument…that the individual dog must have been mistreated… Nah it may have been the mother or grandmother that was mistreated,
and then epi-genetics have reverted to a wild instinct…
Why the grandmother ? Well the ovum you grew from was made while your mother was a fetus inside the grandmother… Chemical signals from your grandmother may have steered your epi-genetics.
Or, what seems to be happening in our society, which is the exact opposite.
So you end up with a bunch of Justin Bieber clones.
The russian fox experiment has fascinated me for a long time. It was my understanding that we didn’t know what, precisely, causes the change in appearance. It has something to do with adrenaline levels (which has something to do with increased aggression). Neotany also has something to do with it. But precisely why the tame foxes get bushy tails, drooping ears and look like dogs is still a mystery as i understand it. The extremely aggressive foxes they also selectively bred look nothing like the tame ones. Totally different sub-species if you ask me.
And I have read somewhere (and have no idea what it would mean or if it’s true) that poodles are the dogs that are genetically closest to wolves.