Help in finding a forgotten title

[Darryl]

I need help in recalling a title. Humans travel across space and discover a planet with humanoid and a non-human dominant race. After the humans mate with the humanoids, they recreate a vanished superior race. The superior race had split their DNA between the two and divided them by space. The non-human race discovers that they were the superior race pets.

I would appreciate any help in finding this book. Thanks

[Sarah]

I would love to know the answer to that.

[M.L.]

That does sound interesting. Do you have any idea how long ago you read it?

[Darryl]

Probably at least 15 years ago.