Dog Breeds are Created Through Selective Breeding. Basically, a breed is started when someone decides they want a dog with a specific set of traits. To accomplish this, they breed two carefully chosen dogs that (ideally) each has the desired traits in hopes they have puppies with the desired traits. When the puppies are born, the ones that display the desired characteristics are bred to each other or back to their parents. Normally this process is repeated over many generations until those traits 'breed true', which means the dogs are bred together until the desired traits reliably appear in each of the puppies. During the course of a selective breeding program, only the dogs with the desired characteristics are bred. Dogs that do not display the desired traits, and therefore don't have the desired genes, are removed from the breeding program. As the dogs become more and more similar, a smaller and smaller gene pool develops. This creates a group of inbred dogs as each is related to all the others. The more closely the dogs are related, the more inbred they are. After many generations of breeding for the selected characteristics, the dogs left in the breeding program reliably pass on their physical characteristics and temperament because they only have the genes that are responsible for producing the desired traits. Dogs without these genes have all been eliminated from the breeding program. The challenge is that while the desirable traits are being isolated, undesirable traits are also produced. These undesirable traits can be something as harmless as an unwanted coat color or they can be a combination of genes that result in a health problem for the dog. This is what is called a genetic disease. A genetic disease occurs when a combination of genes is created that results in an undesirable abnormality that prevents the animal from living a normal, healthy life. Inbreeding can not only result in health problems but in temperament problems too. Because all purebred dogs are inbred to some degree, it is very important to choose a knowledgeable, responsible breeder. A skilled, responsible breeder is aware of a breed's potential genetic problems and works hard to arrange matings that consider the genetic risks involved. This reduces the chance of a genetic disease that may not show up in the puppies for months or even years, while at the same time passing on the desirable traits of the breed. You will learn how to find these breeders later in the eBook. More information that adds to your understanding of the genetic health problems in purebred dogs can be found by clicking "Next Page" below. However, if you are pressed for time and want to move through this book as quickly as possible, you can skip this additional information.