@imbj - Thanks for posting this... any treatments for this in dogs is great and great that there is ongoing research ongoing for all cancer in dogs and humans too!
Tame Russian foxes
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Okay, now that I have re-read some info I have on this. This is apparently an example of a promoter sequence change. Promoters are essentially regions of DNA which help turn on (or off) the expression of certain genes. Even small changes to the sequence of the promoters can have a large impact to the expression of certain genes. So in this case, as temperment was selected for, one or more promoter sequences which impacted those temperment-related genes (or more correctly genes which altered the brain development of the foxes to keep them in a more juvenile state) changed. One or more of these same promoters apparently controlled the expression of the genes related to other attributes such as coat color. So the genes weren't necessarily being changed themselves, just the regions of DNA which were turning them on or off were.
Hopefully that makes sense.
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Okay, now that I have re-read some info I have on this. This is apparently an example of a promoter sequence change. Promoters are essentially regions of DNA which help turn on (or off) the expression of certain genes. Even small changes to the sequence of the promoters can have a large impact to the expression of certain genes. So in this case, as temperment was selected for, one or more promoter sequences which impacted those temperment-related genes (or more correctly genes which altered the brain development of the foxes to keep them in a more juvenile state) changed. One or more of these same promoters apparently controlled the expression of the genes related to other attributes such as coat color. So the genes weren't necessarily being changed themselves, just the regions of DNA which were turning them on or off were.
Hopefully that makes sense.
You lost me at "okay"
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Okay, now that I have re-read some info I have on this. This is apparently an example of a promoter sequence change.
I don't have the paper, so forgive me. I have read about this experiment several times in other books, but just generalizations, never the papers themselves.
So are they saying all of these traits that modify together are under a single promoter, like several splicing variants or several exons in a single gene?
Or was a transcription factor that binds the promotors for many genes what was modified (e.g. TATA Binding Protein, etc)?
Is this just their hypothesis, or have they identified the differentially expressed gene products and their common promoter?
I would love the reference if you have it.
-Nicole
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You lost me at "okay"
How about this,
You have a lightswitch (promoter) in your house that turns on a lightbulb in the kitchen (gene 1, temperment), and the living room (gene 2, coat color). Now you replace the existing lightswitch with a new fancy one (selective breeding). When you flip on the fancy light switch it causes the kitchen lightbulb to burn half as bright (less fearful) and the living room lightbulb to blink nonstop (coat color change). You didn't do anything to change the lightbulbs, you only changed the lightswitch.
The other way to possibly go about this is to keep the same lightswitch but replace the kitchen bulb with one that is half as bright (mutated gene for temperment) and the living room lightbulb with one that blinks (mutated gene for coat color).
So what apparently this is from a genetic perspective (I'm going off of class notes here) is that the selective breeding in this study was basically changing lightswitches instead of lightbulbs.
That is why so many different characteristics can change at once. If you change a lightswitch that controls a lot of different lightbulbs, you are going to have a lot larger impact than if you just change the lightbulbs individually. -
Clay, if you had been my highschool biology teacher, I think I would have not only understood the information more, but also may have passed that class, and as an added bonus, enjoyed it.
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I find the experiment/study very fascinating, but in looking at all the videos, etc., I found myself a little sad that these animals were not just left alone to be foxes as they were meant to be. I know, all dogs were wild once - still, the ones who are not quite totally domesticated to act and feel like our dogs do must be very confused little guys. Just me. I'm sure everything is/was being done to make the transformation as easy on them as possible. We have wild foxes in our neighborhood - my dogs stare at them, they stare back - kind of a wistful thing, IMO.
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Interesting thoughts Nemo.
These foxes supposedly have been selectively bred for 35+ generations. During this time they not only went through a tremendous temperament change but also coat color, ears, and some have twice a year heat cycles. Some Basenjis are starting to have twice a year heat cycles and temperament has definately mellowed in the past few decades. It will be interesting to see what other changes the Basenji will go through when they have been selectively bred for 35+ generations.
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I don't have the paper, so forgive me. I have read about this experiment several times in other books, but just generalizations, never the papers themselves.
So are they saying all of these traits that modify together are under a single promoter, like several splicing variants or several exons in a single gene?
Or was a transcription factor that binds the promotors for many genes what was modified (e.g. TATA Binding Protein, etc)?
Is this just their hypothesis, or have they identified the differentially expressed gene products and their common promoter?
I would love the reference if you have it.
-Nicole
Unfortunately I don't probably have the level of detail you'd like. This was from notes I took during a lecture. It was used as one of the examples, which was probably dumbed down a bit. There is a book though that has some of that information as related to dogs, but I'll have to get back to you once I find the title. Regardless, the "lightswitch" analogy is still somewhat apt regardless if it is an actual promoter region or other parts of the regulatory sequence. My very limited grasp of the area is that the changes observed are believed to be due to changes in the frequency and amount of expression of genes versus functional mutation of specific genes which is much more difficult. And the changes to those regulatory sequences appears to cascade into the expression of a wider range of genes (such as coat color, etc.).
Similar reason apparently for differences between dog breeds. Found this interesting
article. There are a variety of other ones out there if you google the subject. http://www.pnas.org/content/101/52/18058.fullEnjoy! :eek:
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Clay, if you had been my highschool biology teacher, I think I would have not only understood the information more, but also may have passed that class, and as an added bonus, enjoyed it.
Thanks.
I'd be a horrible biology teacher though…closest thing I took was biochemistry. :rolleyes: -
That is too funny that you responded now, as I have 2 other tabs open with papers on the experiment. One from 2005, and one from 2007.
Have just downloaded them, and will start reading soonI had also never heard of operons (multiple genes under control of a singe promoter) in eukaryotes. The dogma I was taught was: One gene, one promoter in eukaryotes. Operons only in prokaryotes.
So I was thinking it had to be a transcription factor change.
But apparently a small number of operons have been very recently identified in eukaryotes, so I have a 2002 and a 2004 paper I am looking at about that.Fascinating stuff. I am never going to graduate.
-Nicole
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That is too funny that you responded now, as I have 2 other tabs open with papers on the experiment. One from 2005, and one from 2007.
Have just downloaded them, and will start reading soonI had also never heard of operons (multiple genes under control of a singe promoter) in eukaryotes. The dogma I was taught was: One gene, one promoter in eukaryotes. Operons only in prokaryotes.
So I was thinking it had to be a transcription factor change.
But apparently a small number of operons have been very recently identified in eukaryotes, so I have a 2002 and a 2004 paper I am looking at about that.Fascinating stuff. I am never going to graduate.
-Nicole
Focus! You can read dog genetics articles once you graduate.
