An individual dog can actually have three genetic parents:

https://en.wikipedia.org/wiki/Chimera_(genetics)

"An animal chimera is a single organism that is composed of two or more different populations of genetically distinct cells that originated from different zygotes involved in sexual reproduction. If the different cells have emerged from the same zygote, the organism is called a mosaic. Chimeras are formed from at least four parent cells (two fertilised eggs or early embryos fused together). Each population of cells keeps its own character and the resulting organism is a mixture of tissues. There are some reports of human chimerism."

Here's a picture of "Tiger", a chimeric dog:

http://stories.barkpost.com/chimera-dogs/

And scientists can now create babies with three genetic parents:

https://www.newscientist.com/article/2107219-exclusive-worlds-first-baby-born-with-new-3-parent-technique/