Meanwhile, researchers are hoping to develop transgenic
pigs whose hearts and kidneys could be transplanted to needy humans. Transgenic
technology could also help in treatments for emphysema and burn victims.
Because creating transgenic animals is extremely difficult and costly, even
more difficult and costly than cloning, researchers are hoping to use cloning
techniques to make multiple copies of the transgenic animals they make.
Cloning could also revolutionize animal testing by reducing
the number of animals required to test an effect. Cloned test animals could
eliminate the variability cause by genetic differences and provide clearer
results, even with many fewer animals.
Another potential benefit--in fact, the original aim of
the Dolly experiment--would be to increase food yields from livestock and
crops. Selective breeding has long been used to increase food yields, but
cloning could speed the process by making it possible to make multiple copies
of, for example, the perfect tomato plant. On the down side, cloning of
livestock or crop plants would weaken the genetic diversity that keeps animal
populations safe from catastrophic epidemics.