Scientists Clone Pig

Aug. 16 -- Her name is Xena, but she’s no warrior princess.

Xena is a scrappy, black-coated piglet born from a white-coated sow. As a swine produced by cloned genetic material from fetal pig cells, Xena represents the latest living milestone in the rapidly evolving field of genetic cloning.

She is named after the field of research that scientists hope her birth might advance — xenotransplantation — the use of genetically modified animal organs for transplant into humans.

“By bringing animal organs one step closer to being transplanted into human beings, we hope to one day overcome the desperate shortage of donor organs,” says Elizabeth Fagan, a professor of medicine and pediatrics at Rush Presbyterian at St. Luke’s Medical Center in Chicago.

Pig tissue and organs, particularly the liver, are thought to be similar to human’s and hold the best possibility for human transplant. But Fagan explains that even with the successful cloning of a pig, scientists still must find methods of ensuring pig’s organs aren’t rejected in the human body and are able to function in human hosts.

“Regardless if they’ve cloned a sheep or a pig, we don’t know how the organs handle human material because pigs don’t go around eating caviar or french fries or drinking alcohol,” she says.

Xena Not the First

Xena isn’t the first cloned pig to enter the world. That honor belongs to a litter of five cloned piglets born in March at the Scotland-based PPL Therapeutics — the same laboratory that produced another famous female, Dolly the cloned sheep. The procedures both groups used are being published separately this week in two major science journals.

In this week’s issue of Science, lead author Akira Onishi of the National Institute of Animal Industry in Japan explains his team used the same techniques developed by researchers at the University of Honolulu to clone mice.

To create Xena, scientists used a needle-like pipette to inject genetic material from fetal pig skin into eggs that had been stripped of their own genetic material. Next, the team stimulated the injected eggs with an electrical pulse that triggered them to develop into embryos. Those embryos were then transplanted into four surrogate sows.