The effectiveness of selective breeding is obvious in cases where the mode of inheritance is known and a single or small number of genes are involved. Coat color in Labrador retrievers is a relatively simple example to understand. In this case the genetic type of one's breeding stock can be established by relatively inexpensive genetic testing and a line of any of the three accepted colors established by selective breeding in very few generations. The lines so created will breed true forever (barring mutations caused by chance or some external influence.)Neil wrote:...
I also question the whole effectiveness of selective breeding. Humans without any regard to breeding (except for the Mannings) set new speed records in track and swimming every couple years, while race horses and greyhounds, where millions are spent on breeding, have not set a track records in 30 years.
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The examples you give as counter examples are not obviously examples of measures attributable solely or perhaps even primarily to behavioral characteristics of the humans or other animals mentioned. Is their evidence that human athletic performance would not rapidly benefit from a selective breeding program? What were the Soviets up to during the cold war years? Could it be racehorses and greyhounds have reached the pinnacle of performance determined by physical structure through the breeding programs of the past? The whole doping thing clouds athletic performance records of late.
Perhaps you meant to restrict your doubt of the effectiveness of selective breeding to behavioral characteristics? If so further study may convince you otherwise. One might start with http://en.wikipedia.org/wiki/Domesticated_silver_fox
and go on to references found there or through a Google search for some obvious key words.
I have been told line breeding Labradors which point will produce dogs too sticky to be useful in but a few generations - the number five was mentioned. I have not seen supportive data, but I have seen Labradors I am pretty confident did point as a natural inherited act. As counterpoint, I am not confident a large percentage of so called "pointing Labradors" do so.
One thing I have wondered about and some members here might shed some light on is the possible recent evolution of "point" in pointers. I've read occasional references to litters of EPs which display (or individuals in the litter display) rather weak 'point. By this I believe is meant point does not appear as early as one might expect and much knock/chase may be required to finally get the dogs pointing. Other measures of "strength" of point might be meant. They may display a point which needs frequent work to remind the dog of the rules - suggesting it is a learned behavior rather than inherited. If this is real a discussion of why and how this could happen and what it may mean about the "genetics" of the dogs might make an interesting topic for another thread.
Another example is similar evolution of some salient characteristics of the Labrador retriever. I have one here that is, among other things, really marginal with respect to the tendency to carry things in his mouth compared to my several prior Labs. Yes, he will grab something offered, apparently with joy, and carry it for a few yards or tens of yards but then he puts it down and loses interest. On a scale of 0 to 9 I'd score him in the 1 - 3 area. He could be an anomaly or indicative of breeding programs misdirected in some way.
There will always be a distribution of the "level" of such attributes in any breed or line (as long as we don't end up with lines of clones). But if the selective breeding program is working for the betterment of the breed or line the spread from the best individuals to the worst should get narrower over generations or at least remain stable while the average moves towards "better" or is stable. To begin to see the distribution of some important hallmark characteristic such as "point" in EPs or "carry" in Labrador retrievers widen and/or the average to move towards "poorer" says something is going wrong in the overall breeding program.
I have no doubt "point" is inherited. I have no doubt a behavior which mimics "point" (at least superficially) can be learned by a some dogs through experience. I have no doubt such a behavior can be trained by active effort of a sufficiently motivated human interacting with some dogs. What is really interesting is whether such behaviors can be told apart by observing them and too what the differences in the DNA might be. Dr. Neff probably needs money to do the work!
Jere