National Geographic has an article on mixing human genomic material with animals. I have used this several times. Twice in the pig stories at KeithGraham.com and in several unfinished stories.

This article describes Chinese scientists using rabbits as a medium to grow human stem cells, by injecting human DNA into rabbit cells. There is also a reference to pigs that have been altered to produce human blood.

This is good source material for “near future” SF that zine editors are always requesting.