First off, don’t be sorry for stating an opinion Ina, it’s yours and one of the great things we can enjoy is the fact we can say what we think! (So long as we stay civil)
Now as for the genetic determination, I still beg to differ, so I will expand on my previous argument, I’ll try to keep it simple, but I apologize in advance if it gets a little technical.
Statistical analysis of the type which Wiesner and Willer must have used (roughly 20 years ago I presume?) is based on the observation of phenotypes. You don’t actually take into account the genetic make up of the animal at all, but you infer genetic information from the phenotypes which you observe.
Now this approach is theoretically perfect, but it is very difficult with this kind of approach to take into account environmental effects, especially those environmental effects that you cannot foresee.
Let me give you a somewhat silly but illustrative example. Lets say there is an isolated colony of female birds (we shall call them fems for now). Now these fems have a number of traits which are genetically determined, their plumage can be blue or grey, their tails can be long or short and their eyes can be black or grey. Now every so often a male fem flies in to mate. Every year it is this same male (lets call him prince charming) who comes to mate. Prince charming has a preference for female birds which have short tails and blue plumage. If you carried a study out on the reproductive success of these birds, you would reach the conclusion that you are faced with a situation where there is a strong correlation with genetics, and a multigenic situation at that. Fair enough. But then prince charming dies and now it’s the black prince who comes to visit the colony, and the black prince has a penchant for females who have grey plumage and black eyes. If you were to continue your study your data would become rather skewed, and you would have lots of trouble defending this data. The reason? You were using a statistical analysis to measure an environmental factor (the preferences of prince charming) even though this factor does have a genetic basis.
My argument is that something very similar applies to dogs and cryptorchidism. The basis for this argument is the actual process of testis migration, which is not only complex but takes place outside the womb, which is a relatively well controlled environment. It takes place in the living, kicking running puppy!
One must also take into account that the environmental conditions in which dog breeds evolve are particularly odd. The selection of which animal breeds successfully is almost entirely up to human discretion, thus it is the animals which best fit the arbitrary (from a darwiniean point of view anyhow) requirements of their owners. This arbitrary environment would probably not be taken into account in a statistical study which would take place today, much less in one which took place twenty years ago, quite simply because it was taken as a given.
Alright, lots of blabbing, but one can wonder, what the whole point of it all is? Lets say that having a certain shape of a pelvis is going to be a significant factor in whether a dog is cryptorchid or not. So what? Even though it is a morphological feature it is still clearly determined by genetics.
The importance of this sort of thinking is, that if you start to think that the determining factors are perhaps environmental and not fundamentally genetic, you get into a different mindset, and are able to better understand where the actual problem lies, and would thus be in a better position to determine whether a given dog should or should be used for breeding.
I cannot resist but ask… would the morphology of the hindquarters be significantly different in those races with a high degree of cryptorchidism (which you just mentioned) and those which have a low incidence of this? Anyhow, as always, just my idea.
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