understand the magic in the egg that allows it to reprogramme a cell’s DNA,” Lanza says. “But cloning is still essentially a black box” (Anon. 2007: 802).
Scientific studies also confirm that genetically identical clones can differ substantially. A carefully controlled study using pigs tried to separate out the effects of cloning from environmental effects. This pig study used age-, breed-, and sex-matched clones and control animals housed under the same conditions (Archer et al., 2003). If clones were “identical twins” separated by age, one would expect there to be lower variability in virtually all the parameters looked at among the clones compared to the controls as the clones have far less genetic diversity compared to the control animals. Interestingly, there were a number of traits where the clones were just as variable, or more variable, than the control animals. For example, the weight of the cloned pigs at 27 weeks was just as variable as non-cloned pigs of the same age; indeed, one of the cloned pigs weighed about 10 kilograms less than any of the control pigs. Blood chemistry data also revealed two groups of traits: one in which cloned pigs had less variability than controls (as expected) and one in which clones had the same variability as control pigs. The authors conclude that cloning “increases the variability associated with some traits. This finding is contrary to the expectation that cloning can be used to reduce the size of groups involved in animal experimentation” (Archer et al., 2003: 430).
New Zealand scientists got similar results in a study of cloned cows that carefully controlled for outside factors—such genetic background of the fetus, age of the surrogate recipients and their reproductive—that could cause variability. If clones are simply “identical twins born at different times,” then they should show less variability for the various placental and fetal measurements. The authors were surprised to discover “greater variability within the cohort of NT fetuses with the same nuclear genetics than within the cohorts of AI and IVP fetuses, given that sexual dimorphism in the growth of AI and IVP fetuses is expected to increase the variability within these two control groups. This suggests that nuclear genetic background alone does not account for the phenotype. The cause of this variability is unknown” (Lee et al., 2004: 9).
Viagen, a cloning company, supplied FDA with a data set on cloned pigs and offspring of cloned pigs. Interestingly, cloned pigs, when mated to non-clone pigs cause a greater variability in litter sizes—cloned boars produced many more very small litters and very large litters than normal boars. If clones were just identical twins, we’d expect there to be less variability in litter size in offspring of clones compared to offspring of non-clone comparators.
Clones Pose Unique Risks
The notion that cloning poses “no unique risks” compared with other artificial reproductive technologies is highly misleading. First, by focusing only on whether or not “unique risks” occur with cloning ignores the importance of quantitative differences in risks between cloning and other reproductive techniques. Over 90% of cloning attempts end in dead animals. The figures are even worse if you consider the production of healthy offspring. According to a recent article in Nature on the tenth anniversary of