. With exclusive access to the leading scientists who made Dolly - Dr Ian Wilmut, Dr Keith Campbell and their team at the Roslin Institute in Edinburgh - HORIZON tells the extraordinary story of their struggle to achieve the Holy Grail of embryology.
It all began in the 1980s when Dr John Clark and Dr Wilmut tried to create transgenic sheep which could make valuable pharmaceuticals in their milk. But the technique struck gold just once in every hundred attempts. The scientists yearned for a solution to make the technique cost-effective. A chance conversation in a bar alerted Dr Wilmut to another possibility: cloning.
All cells contain all the genetic information to create a new individual, but once cells divide and become specialised for a task in the body, it was thought that the rest of the genes would no longer be effective. Dr Wilmut discovered that reprogramming a cell once it had specialised might be possible. He immediately set about building a team capable of taking on this challenge.
But they had competition. Deborah Cadbury's enthralling film reveals how an American team was on the brink of success, planning 1000 cloned cows, when their research was hit by financial difficulties. They had also run into weird experimental results, such as the birth of giant calves. Some were almost 13 stone - twice the size they should have been.
In Edinburgh, the Roslin team managed to take a specialised cell from the mammary gland of a six-year-old sheep, introduce it into an unfertilised egg cell which had had its nucleus removed, and implant it into a third sheep which acted as surrogate mother. DNA analysis revealed that Dolly was born with exactly the same genetic makeup as the original six-year-old sheep.
Dolly overturns one of the central tenets of developmental biology, that once a cell has specialised, its genetic material cannot be reprogrammed. She also heralds new commercial possibilities and an ethical nightmare. The Roslin team believe that human tissues should not be cloned, but others argue cloning could save lives. Even if cloning whole humans was abolished, cloning organs could meet our need for perfectly matched transplants.
Inhibiting the development of a cloned embryo to make an organ wrapped in a bag of skin is just one of a myriad of ethical problems raised. Would women be prepared to allow such a creation to grow in their wombs? Does living tissue possess a soul?
