Take a good, hard mental image of a long line of people stretched for blocks. If you expand the line to roughly 100,000, this is the number of people waiting for an organ transplant. The imbalanced patient-to-organ ratio leaves many to die while waiting their turn. In response, some researchers try to tap into animal organs to save human lives, but those organs do not always work.

Research in the University of Missouri’s Division of Animal Sciences may help solve this medical debacle by using genetic modification. When an organ goes from one animal to another (like to a human), preexisting antibodies in the human bind to the organ’s sugar molecules and kill the organ, making it useless. “When you take a pig cell and transfer it to a human, the molecule is immediately recognized as foreign,” explains MU’s Animal Science Professor, Randall Prather. “Within minutes you’ll get hyperacute rejection, and the cells will be destroyed.”

Prather talks about his work with genetic modification. The modified swine are marked by a green florescent glow on their snouts. Such modifications on the pigs could positively impact agriculture and medicine.

A fundamental medical challenge for species-to-species organ donations involves sugar molecules that are recognized as foreign by preexisting antibodies. Prather and his team have modified pigs by removing the sugar molecule on the surface of their organs and then transferred those organs into baboons. So far the pig kidneys have not caused the kind of hyperacute rejection seen in similar organ transplants.

Prather has contributed to research associated with modifying genes to produce healthy bacon. In a study involving the University of Pittsburgh’s School of Medicine, researchers transferred a gene known as fat-1 to fetal pig cells. The fat-1 gene creates an enzyme that converts omega-6 fatty acids to omega-3 fatty acids, the type of fatty acid known to reduce heart disease and cancer. As a collaborator in the research, Prather cloned the pig fetal cells containing the gene that makes omega-3 fatty acids and creates pigs with their their own omega-3 fatty acids.

Prather gives a tour of the “Wall of Pork and Beef,” which highlights some of the important research projects on which he has collaborated over the years.

• • In his early tests with embryo transfers in pigs, the cloned, genetically modified swine share the distinct characteristic of a green fluorescent snout.


• • Removing the Alpha 1,3-galactosyltransferase (GGTA1) gene in pigs eliminates the deadly antibodies that attack organs coming from a different species.


• • By “co-colonizing the pig liver” (transferring human liver cells into fetal pigs), the pig is born with a liver that is part human, providing another potential source of liver cells for transfer to a person with liver disease.


• • Creating stem cells from skin could lead to useful genetic modifications.


• • In order to find a cure for cystic fibrosis, a devastating lung disease found in humans alone, Prather’s research shows that, with genetic modification, swine can develop the same condition, making it easier to test treatments and therapies for humans.


• • Adding certain genes to pigs has resulted in the protein being produced in the pigs’ milk. The pigs can then be milked and the proteins purified from the milk, which could contribute to the creation of a pharmaceutical treatment for hemophilia.