A question regarding evolution.

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A question regarding evolution.

I was watching a program the other day that was discussing the latest theory on how wolves had become dogs. During this program they mentioned an experiment in Russia where foxes had been selected and bred for tamability. They said that when this was done there were physical changes in the foxes as well, such as changes in coloration, the ears became floppy, and other changes in behaviors such as barking and answering to a name (I would guess this is a change in 'intelligence'(?)). The foxes went through fairly drastic changes in a very short time period. My question is, if all these behaviors, and especially the morphological changes, are expressions of different genes, then how do they relate to the sole selection criteria of tameability? In populations, is it normal that we find that individuals with like temperaments (or any single selection criteria) normally have other common traits? Can we say "Look at so and so's eyes, he must be one mean bastard" (hypotheitcally)?   

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I read about that

I read about that experiment as well.  It seems that whenever humans domesticate an animal we seem to instinctually select traits that resemble the adolescent animal.

Such as the floppy ears and such.  It's like a subconscious thing we direct into which animals are allowed to breed.

So I think all those traits are traits that humans either intentionally or unintentionally select for.  Is this a good animal?  Does it look the cutest?  Does it behave the best, etc. etc.  Ok you get to breed.  I'd like to have more animals like you, you get to make some babies for me.

I've read that humans are actually doing similar things to ourselves without even noticing.

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Watcher wrote: I read

Watcher wrote:

I read about that experiment as well. It seems that whenever humans domesticate an animal we seem to instinctually select traits that resemble the adolescent animal.

Such as the floppy ears and such. It's like a subconscious thing we direct into which animals are allowed to breed.

So I think all those traits are traits that humans either intentionally or unintentionally select for. Is this a good animal? Does it look the cutest? Does it behave the best, etc. etc. Ok you get to breed. I'd like to have more animals like you, you get to make some babies for me.

I've read that humans are actually doing similar things to ourselves without even noticing.

I believe in this instance, from what I gathered from the show, the animals were selected only for tamability. They were selected based on their response to having a gloved hand stuck into their cage. The animals that were non-agressive to the gloved hand were bred. 

The differences in coloration and the floppy ears and such apparently were not necessarily traits that were expressed in the breeding animals, but were traits that came about within a few successive generations. They just seemed to be somehow linked to the genetic expression of tameness, not artificially selected for.

Apparently, much like they think may have happened with the wolf, tamability, or shorter flight distance in the wolf's case, was the sole selection criteria but through this selection criteria significant morphological changes came about within a few decades. The reason why this occurs is what I am asking about.

In the wolf's case it was very likely a completely natural evolutionary process (unlike the fox in the experiment that was selected and bred specifically for the experiment). I find it odd that selecting for a behavorial component can have impact on the physical structure of the animal, the fox with floppy ears and coloration change and the wolf with a smaller size and shorter muzzle. I was hoping someone might be able to explain why this occurs, or is something we should expect to occur.  

“Philosophers have argued for centuries about how many angels can dance on the head of a pin, but materialists have always known it depends on whether they are jitterbugging or dancing cheek to cheek" -- Tom Robbins


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Vessel wrote: I believe in

Vessel wrote:

I believe in this instance, from what I gathered from the show, the animals were selected only for tamability. They were selected based on their response to having a gloved hand stuck into their cage. The animals that were non-agressive to the gloved hand were bred. 

The differences in coloration and the floppy ears and such apparently were not necessarily traits that were expressed in the breeding animals, but were traits that came about within a few successive generations. They just seemed to be somehow linked to the genetic expression of tameness, not artificially selected for.

Apparently, much like they think may have happened with the wolf, tamability, or shorter flight distance in the wolf's case, was the sole selection criteria but through this selection criteria significant morphological changes came about within a few decades. The reason why this occurs is what I am asking about.

In the wolf's case it was very likely a completely natural evolutionary process (unlike the fox in the experiment that was selected and bred specifically for the experiment). I find it odd that selecting for a behavorial component can have impact on the physical structure of the animal, the fox with floppy ears and coloration change and the wolf with a smaller size and shorter muzzle. I was hoping someone might be able to explain why this occurs, or is something we should expect to occur.  

It's certainly interesting to investigate this.  I'll admit I've just read a few brief articles.  So I'm open to new experiments and results to explain the traits you have mentioned.

I'm just throwing out there what I have read about it.  I don't really know.

"I am an atheist, thank God." -Oriana Fallaci


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The first trait in any

The first trait in any domestication process chosen for would be relative docility. In a pack animal, additional requirements would entail establishishing one's self as superior.

In the case of a preadator, like a wolf, the domestication would likely take a bit longer than simply grabbing a tasty herbavoir of the plains.

First, there are hundreds of accounts of humans communing whith wild predators. The canine species, for whatever reason, seem receptive to this. Food left out attracts them, and they seem to have marginal fear of humans. They are obviously prime species for domestication. They are, also, at least individually, relatively easily dominated by a human.

I simply think of "Dances With Wolves" as cheesy as I thought the film was, I think that's the sort of initial relationships we'd be looking at.

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Experiments with fruit

Experiments with fruit flies and immunity to DDT have taught geneticists something surprising.  Basically, if you mess with one gene you mess with another.  Some fruit flies selected for immunity to DDT tend to form into circular formations on the glass walls of their container.  There were other anomalies too but it has been so long that I can't remember.

Selecting for something as complex as reliable docility must involve several sets and combinations of genes.  Foxes are not pack animals.  One of the reasons wolves were so easily domesticated was because they are born as members of a pack and there is only one breeding pair per pack.  Wolves are born and expect to remain subservient to the alpha leaders.  Man simply became the new pack alpha.

I wonder if these new foxes are truly domesticated yet.  Or do they fade into the wilderness at the earliest opportunity?  Docility is one thing.  Trusting enough to overcome a solitary nature and form a partnership is probably a whole other set of genes and unexpected changes.  They may end up looking like cats.


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OccamsChainsaw

OccamsChainsaw wrote:

Experiments with fruit flies and immunity to DDT have taught geneticists something surprising. Basically, if you mess with one gene you mess with another. Some fruit flies selected for immunity to DDT tend to form into circular formations on the glass walls of their container. There were other anomalies too but it has been so long that I can't remember.

Selecting for something as complex as reliable docility must involve several sets and combinations of genes. Foxes are not pack animals. One of the reasons wolves were so easily domesticated was because they are born as members of a pack and there is only one breeding pair per pack. Wolves are born and expect to remain subservient to the alpha leaders. Man simply became the new pack alpha.

I wonder if these new foxes are truly domesticated yet. Or do they fade into the wilderness at the earliest opportunity? Docility is one thing. Trusting enough to overcome a solitary nature and form a partnership is probably a whole other set of genes and unexpected changes. They may end up looking like cats.

Yes. This is what I was getting at. If I was undrstanding correctly what was being said it seems that by intentionally selecting for the genetic expression of docility there were physical changes in the animal that came about. It seemed odd to me that one specific selection criteria could have such broad effects. I was also amazed by the very short period of time (less than forty years) in which these changes came about.

The program itself was about how wolves likely became dogs, not by any active intervention by man, but by scavenging from refuse dumps and thereby succumbing to the selection for docility as expressed in flight distance, or how close they were willing to stay to human activity. In the scenario presented, wolves became dogs, physical changes and all, in a very short time period simply because the ones willing to stay close to the food source gained an advantage over those who fled. As with the foxes in the experiment, this behavioral selection criteria was sufficient to cause dramatic morphological changes in the period of perhaps only a few decades.

I found this fascinating as I had no knowledge of the fact that genetic expressions of behavioral and physical aspects of an animal were intertwined in a way that could cause this to happen. Is it a matter of some genes or sets of genes being expressed in more than one manner or is it that changes in one set of genes somehow affects another set of genes?

(In case you can't tell, my understanding of evolution is farily basic, mainly confined to the broad concepts.) 

“Philosophers have argued for centuries about how many angels can dance on the head of a pin, but materialists have always known it depends on whether they are jitterbugging or dancing cheek to cheek" -- Tom Robbins


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Here's a link that talks

Here's a link that talks about coat color and selection pressures in domesticated animals.

 

http://www.ratbehavior.org/CoatColor.htm


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OccamsChainsaw

OccamsChainsaw wrote:

Here's a link that talks about coat color and selection pressures in domesticated animals.

 

http://www.ratbehavior.org/CoatColor.htm

Wow! Thank you very much. That was exactly what I was looking for. I getted more smarter today! 

“Philosophers have argued for centuries about how many angels can dance on the head of a pin, but materialists have always known it depends on whether they are jitterbugging or dancing cheek to cheek" -- Tom Robbins


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