Table 3.

Advantages of the usage of pig as a donor compared with non-human primate.

	Pig	Non-human primate
Advantages	•Less ethical concern •Comparable size and physiology •Easy to breed •Relatively inexpensive cost of breeding •Multiple litters •Lots of experiences in genetical modification •produced in germ-free or pathogen-free conditions.	•Phylogenetically the most similar to humans
Disadvantages	•Intermediate phylogenetical distance to human	•More ethical concerns •Small organ size •Easy zoonotic transmission of infection •Long time of breeding •High cost of breeding •Low number of litters •Lack of experience in genetic modification