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Реферат: Genetic characteristics of designer dogs
E.R.Islamova
student, 4th course
Bashkir State Agrarian University, the Veterinary Medicine Department, Russia, Ufa
MalikaFly@gmail.com
Cand.Biol.Sci. , G.V. Bazekin, Scientific Adviser
Cand.Phil.Sci., the senior lecturer, O.N. Novikova, Language Supervisor
A new trend has begun in the dog world and many have referred to it as an emergence of designer dogs. In fact, designer dogs can be more expensive than purebreds due to the increased demand for them.
In contrast to mixed breed the designer dog has a definite structure. The designer dog breeds, also known as hybrid dogs, are basically the product of a mating between two purebred dogs of different breeds. The first generation designer dog (know as an F1), is the direct result of mating two purebred dogs of different breeds. The second generation (F2) results from the mating of two F1 dogs. Today, a designer dog is described as a cross between two purebred dogs, bred over many generations to breed true for looks, and exhibiting the ancestral temperament and characteristics.A standard is established that breeders must follow. Only dogs which make the written standard are to be bred. It is not advisable to select a dog based on appearance alone.
An important consideration is that every purebred dog breed is troubled by at least one (and usually many more), genetic or hereditary illnesses or problems. This is due to the level of inbreeding that takes place in order to keep a breed 'pure'. Available researches show that designer dog breeds, and mixed breeds, are less likely to suffer from genetic weaknesses and are generally healthier overall than their purebred cousins. First-generation hybrids tend to be fairly uniform in type, because each has one set of genes from one parental breed and one from the other, and each parental type has limited genetic variation. However, it's very important to pay attention to the specific purebreds that are producing a particular hybrid/designer dog. If both parent dog breeds share the same genetic weaknesses, there's at the potential for a double dose of problems in the resulting puppies. For example, if you cross breed two purebreds who each have a predisposition towards eye and eye-lid problems (such as Pugs, Boston Terriers or Pekingnese), the puppies are very likely to have problems in this area. And they may be more serious than in the original breeds themselves.
Admittedly one of the first designer dog breeds was the Labradoodle, which was originally bred in Australia in the 1970s. The creation of Labradoodle, as an example, also had the purpose of providing an allergy-friendly companion, especially to people with special needs. The Labrador Retrievers' superior performance as a service dog, and the Poodles' non-shedding, non-allergenic coat. This combination produced a great guide dog for people with allergies. It works quite well in theory, but due to the nature of genetics, it's not always a 'sure thing'. An F1 (first generation) Labradoodle or Goldendoodle can have a lab like coat that sheds, an F2 is more likely to have a hypoallergenic, low to non-shed coat. An experienced breeder can probably give a good assessment as to what characteristics to expect as the puppy grows. For example, with the Labradoodle, a breeder might be able to tell which type coat the pup will have, meaning characteristic of the Poodle or the Labrador, but it cannot be guaranteed. It can shed or not shed. Dogs in the same litter can vary, and it is harder to tell what type of temperament the puppy will have since some characteristics are not evident until the puppy is past the usual adopting age. When considering a designer dog, it's also not safe to expect puppies from a certain breeding to get only the desirable physical/behavioral traits. They're just as likely to inherit the undesirable ones, and each individual puppy in the litter can be quite different from it's litter mates.
When it comes to being able to predict the size, temperament, coatand breed specific traits that a puppy will develop as it matures, designer dog breeds fall somewhere in the middle range. Unlike purebred dogs, with a hybrid, you don't know exactly what the temperament, size or exact look of the dog will be. Breeding two different types of purebred dogs together can produce puppies with any combination of the various characteristics found in either breed. Although every puppy is a unique individual, and will not look or act exactly like it's littermates, it's much easier to determine the above factors in a purebred dog. For example, all puppies of guardian breeds will naturally develop a desire to guard and protect their owners. Some obviously will feel more strongly about this than others, but it's there nontheless. In the same way, puppies from the herding breeds will want and need to herd things, and this will be accompanied by a high energy level. At the other end of the spectrum, a mutt, or mixed breed puppy of uncertain ancestry is totally unpredictable. His parents are probably mixed breeds themselves, with their own individual jumble of genetic traits.
On the other hand, hybrids/designers dogs produce puppies that fall somewhere in the middle.
They're not even close to being as predictable as a purebreed dog, but F1 and F2 generation hybrids will show a selection or combination of characteristics found in the original purebred dogs that founded the new 'breed'. It's also important to realize that each individual designer dog breeders' stock will vary from those of another breeder, as there are no recognized 'breed standard' to adhere to (as there is with purebred dogs). The 'look' of each designer dog breed is pretty subjective.
The knowledge of genetic characteristics of designer dogs is essential for developing disease-resistant individuals preserving the desired features of breed.