Clones could have long-term health problems

Cloned animals could suffer from serious genetic defects, according to a paper published in the Lancet. The authors report that a calf cloned from an adult cell may have died because of errors in its genetic reprogramming. Although there have been many reports of clones dying during or shortly after pregnancy, this is the most detailed report to suggest that the process of cloning could have long-term deleterious effects. Jean-Paul Renard and colleagues of the Institut National de la Recherche Agronomique in Jouy-en-Josas created a clone of an existing cow. Routine tests on the resulting calf started to pick up mild abnormalities in blood cell production which later led to severe anaemia and premature death. An autopsy found that lymphoid tissues had failed to develop normally. The researchers argue that despite the possibility that the calf died of a mutation there is a real possibility that the cloning process itself could have interfered with the reprogramming of the clone's genetic instructions in the donor cell.