I am looking to identify a novel or series of books where the human race it at war with an alien race.
As the story (or series) progresses, it turns out that there is only one race of aliens in the galaxy (could potentially be the universe), all alien races are based on "human" stock, humans of earth just being one variation. The galaxy has been seeded with humans by a more ancient race. The race of aliens the human race was originally at war with is a bio-engineered former servitor race.
Edit: Thank you to those below that have asked for extra details.
I seem to remember that the situation of the seeding of the galaxy with human based intelligence was described to the protagonist at some forum/meeting where they discussed the various differences in the races, extra ribs etc were really superficial variations on a theme.
I also think that the (engineered) alien race at war with the humans of earth is wolf/dog-like, or that is the image I have of them.
I am guessing, but I think I must've read this in the late 90s or 2000s.