Complex sentence: The German Shorthaired and English pointer gene pool is restricted by the fact that they are registered breeds, but they too were bred for performance; the Scandinavian pointers from which the first Eurohounds came had been used historically for sled dog racing and hunting.
Split into simpler sentences: The German Shorthaired and English pointer gene pool is restricted by the fact that they are registered breeds, but they too were bred for performance. The Scandinavian pointers from with the first Eurohounds came, had been used historically for sled dog racing and hunting.