
The first thing to understand is that a pedigree is only a list of ancestors, whether for a dog, cat, horse, person or whatever.
(Technically the individuals in that pedigree do not need to be of the same breed as each other - they just have to be recorded.)
However, it's usually taken to mean the written record of the ancestors of a purebred animal.
Any clearer, or have I just muddied the water?
:)