Im more and more disappointed all the time

[Guest Anonymous]

here is a very interesting read about pure breds vs mutts i came across few days ago.

[url]http://www.paws.org/cas/resources/fact_sheets_dogs/purebredproblems.php[/url]

[Canis erectus]

On the subject of mixed vs. purebred dogs my feeling is that mixed breeds have a lesser tendancy to develop congenital health problems than pure breds. They can certainly still get all the same problems a pure bred can but I do believe they are less prone to it, due primarily to the hybrid vigor theory. While mixed breeds are nor technically hybrids, they do differ morphologically and genetically enough that they should be classified as seperate sub species at the least, so hybrid vigor still applies. Basically a hybrid tends to be greater then the sum of the parents, nature just seems to have a way of making the best of what genetic material it has to work with and is partially why a hybrid often displaces both parent species in the wild. Though it is worth noting that you can still sometimes get the worst of both parents depending what reccessive genetic and behavioral traits are in the parents.

The reason for the modern purebred dogs having so many health problems is do to irresponsible breeding. Breeders who fail fail to recognize and cull dogs with health or behavioral problems only add to the groeing list of problems for a breed. Over the centuries (primarily over the last 30 or 50 years or so probably) maligned inheritable traits have accumulated in many different breeds, so much so that for some breeds (GSD's for example) it's difficult for even the most responsible breeder to produce sound dogs.

With all that said (I'm sure most of you already know all of that anyway) I think that it's a common misconception that if you get a mixed breed dog that it won't have the health problems a pure bred does. I've seen many people disappointed with that misconception, because while a mix may be less prone to problems you can't rely on that.

[Canis erectus]

First I'm going to appologize for taking the thread off the original subject. Also, I'll see if I can dig up some info sources for you Ravyn, but to be frank, I'm a learned man and I've read more books, articles, essays, etc. than I'll ever remember.

Now as far as dogs' relative zoolocial placement is concerned I should have stated that this is my theory, though I'm sure there are others who have come up with the same conclusion. Basically just because there isn't a zoologist in the world inane enough to tackle and debate the species relativity of various dog breeds doesn't mean that they aren't genetically different enough to at least be sub-specific to eachother. We already know that each breed has a distinct genetic mapping, but from what I know about zoology there isn't reason enough for anyone to devote the proper time for proper species classification. The major reason for that being that dogs (Canis familiaris) being a domesticated animal have no "natural" relation or impact on "natural" species or habitats. There are some zoologists/archeologists who are attemping to uncover the ancient evolutionary history of dogs in general but that isn't very pertinent to the relationship between modern dogs and other canids. I also believe humans belong in seperate sub-specific classifications, but I have yet to hear anyone crazy enough to want to tackle that sordid mess, the implications of which I'm not even going to get into.

Here's something else to think about. It's generally well though of as modern domestic dogs being primarily decended from European and Asian wolves. A selctive breeding process began (both naturally and man-made) and dogs began to vary from the origional type, eventually becoming Canis familiaris. At what point exactly did that occur? Who can say but if by those guidelines dogs can be considered a different species than wolves, why isn't one breed of dog considered zoologically different from another given that same selective breeding process? What happens when you hybridize a wolf with a GSD and conform it into a breed standard (e.g. Saarloos Wolfdog)? Is it a wolf (Canis lupus)? No. Is it a dog? It's generally considered so, but how can an animal bred from two converging species still be classified as Canis familiaris?

OK, wow this has already become way more involving than I wanted it to be. :D

With regard to hybrids, yes they are typically sterile. However most of those are man made hybrids and are of animals with a resonably wide genetic divergence. In a natural ecology hybridization usually occurs within the sub-specific level or with species that have a narrow genetic gap. In my opinion, too big of a species gap just causes some 'crossed wiring' and genetically weaker offspring (there's probably some studies done on this theory but I don't know). Just because two animals are equines doesn't mean that they share a close enough branch on the evolutionary tree to produce genetically sound offspring. If you want to find some research on the effects of natural hybridization look for Speckled Kingsnakes (Lampropeltis getula (hollbrookii?)) and Florida Kingsnakes (Lampropeltis getula floridana). Those are the two that come off the top of my head that there have been at least some research on. Also a good place to look would in flora, which is probably where hybridization occurs most commonly, both naturally and in man-made situations.

[imported_Kat]

[quote]how the pups turn out depends, GENETICALLY, on the health of the parents. [/quote]

I have to just say that genetics will not always account for the health of the dog. It will also depend on environmental factors. A dog with parents who have 0/0 hip scores a piece could still have Hip dysplasia if fed an incorrect diet/given wrong exercise.

[Canis erectus]

Ravyn, I was able to find this with a quick search ---> [url]http://www.ou.edu/wanglab/FreemanWangEER.pdf[/url]

I wasn't in the mood to do much more than skim through it, but does have some interesting information about plant hybridization.

[Seijun]

[quote]The product of a male tiger and a female lion mating produces some darn big cats, but they are also sterile or produce weak, short-lived offspring. The product of a male lion and a female tiger is much smaller than either of its parents and again...sterile.[/quote]

I know a guy online that has a 3/4 lion, 1/4 tiger mix. I have also seen some long-lived ligers and tigons.

[quote]What happens when you hybridize a wolf with a GSD and conform it into a breed standard (e.g. Saarloos Wolfdog)? Is it a wolf (Canis lupus)? No. Is it a dog? It's generally considered so, but how can an animal bred from two converging species still be classified as Canis familiaris? [/quote]

Since the wolfdog breeds are no longer part wolf, they are considered "dog." The wolves were introduced only a few times. GSD was added to a much greater extent, and the resulting breeds are far enough removed from the wolf additions that any "wolf" genes they carried are long gone.

~Seij