I'm not sure where you got those facts, but pigs definitely do not have similar DNA to us than chimpanzees. Pigs are of the order Artiodactyla, even toed ungulates, great apes are all primates. Yes, we use pigs in medicine alot, because they have similar cellular proteins and organs of the same size. Chimps are a lot harder to come by, and their closeness to
Homo sapiens sapiens makes puts them under protection. It also being revealled that dolphins may not be as intelligent as we once thought, though they are closer to pigs than primates, being ungulates themselves.
I have yet to meet a biology teacher who has said anything to the effect that we are descended from
Pan troglodytes. We are not descended from any modern ape species, but we, like them, are apes.
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Unranked taxon: Synapsida
Unranked taxon: Mammaliaformes
Class: Mammalia
Subclass: Eutheria
Unranked taxon: Euarchontoglires
Superorder: Euarchonta
Order: Primates
Suborder: Haplorrhini
Infraorder: Simiiformes
Parvorder: Catarrhini
Superfamily: Hominoidea
Family: Hominidae
Subfamily: Homininae
Tribe: Homini
Genus:
Homo
Species:
H. sapiens
Subspecies:
H. s. sapiens
