The piglets' birth was less an achievement in the science of cloning and more an advance in the search for a supply of human-ready, transplantable animal organs. This has the potential in the near term to solve the worldwide organ shortage crisis. With 70,000 Americans waiting for organs every year and only 10,000 donating, even the skeptical admit advances in this field cannot come quickly enough. Though monkeys are human's closest relatives, pigs have been singled out as ideal donors because they are widely available and their organs are roughly the same size as those of humans. While pig heart valves are already widely used in human heart surgeries, however, wide use of pig organs won't be possible until the organs are genetically altered to prevent human rejection.
Cloning is a first step to making human-ready pigs.
PPL Therapeutics, which cloned Dolly three years ago, said the five piglets were cloned from an adult sow using a slightly different technique than the one that produced Dolly. The gene triggers an immune response in the human body, prompting it to reject the organ. Three new genes would then be introduced into the pig cells, and the transplant patient would receive a blood transfusion containing modified cells taken from the pig supplying the organ. Scientists hope this process will reduce long-term rejection of the transplanted organ. It is now a case of combining the various strategies into one male and one female pig and breeding from these.