Cloning Facts and Fallacies

Updated May 8, 2019 | Infoplease Staff

Trepidation over humans creating duplicate people began in February 1997 when Dr. Ian Wilmut and his team of scientists in Scotland astonished the world by announcing that they had successfully cloned an adult sheep. Animals had been cloned before using the cells of developing embryos soon after they begin to form in the egg, but this was the first time ever that a mammal had been cloned from the cells of an adult animal. This major scientific breakthrough was accomplished by researchers in Edinburgh at the Roslin Institute, a center for genetic research of farm animals and PPL Therapeutics, a biotechnology company. The goal of their joint effort is to improve conventional animal breeding and create new health products for the biopharmaceutical industry.

In a process called “nuclear transplantation,” researchers took an udder cell of a six-year-old ewe and transplanted the nucleus (which contains the genetic material or DNA) into an unfertilized egg of a second sheep from which its nucleus had previously been removed. The cell and the egg were fused with electric pulses. The egg began to divide normally and developed into an embryo. It was then implanted into a third, surrogate sheep who gave birth to a lamb that is the genetically identical twin of the sheep from which the mammary cells were taken. The lamb named Dolly seems normal and healthy.