How Dolly was created
The idea to clone human beings originated in 1996 when the first cloned sheep was created by adult cell nuclear transfer. She was named Dolly. Earlier, animals had been cloned by using the cells of developing embryos but in the case of Dolly scientists at the Roslin Institute for the first time cloned a mammal from cells of a six-year-old ewe.india Updated: Jan 10, 2003 18:05 IST
The idea to clone human beings originated in 1996 when the first cloned sheep was created by adult cell nuclear transfer.
In 1996 scientists from Roslin Institute in Edinburgh, with its financial partners PPL therapeutics Inc., created a sheep clone, Dolly. The aim of their joint effort was to improve conventional animal breeding and create new health products for the biopharmaceutical industry.
The experiment was an achievement that gave a fillip to animal cloning.
Earlier, animals had been cloned by using the cells of developing embryos but in the case of Dolly scientists for the first time cloned a mammal from cells of a six-year-old ewe.
Nuclear transplantation steps taken by the scientists to create Dolly:
They took an under cell of a six-year-old ewe
Transplanted the nucleus containing the DNA into an unfertilised egg of a second sheep. The nucleus of the unfertilised egg had previously been removed.
The cell and egg were fused with electric pulses
The egg began to divide normally and developed into an embryo
The embryo was then implanted into a third, surrogate sheep who gave birth to a lamb, genetically identical twin of the sheep from which the mammary cell were taken. The lamb born was named Dolly.
However, there have been reports that Dolly had premature arthritis. Scientists feel that cloning might not necessarily be the reason as Dolly’s arthritis can also be as she was overweight.
What still questions the practicability of cloning is the fact that Dolly was created after 276 experiments. The rate of success has not changed much during the years. After Dolly’s creation cat, dog, cow, pig, mice and monkey have also been cloned but then none of the experiments have been successful in the first trial. Many have died before birth or are born with severe abnormalities. Even though the technique to clone is the same, the process is critical and the success rate is extremely low.
In view of the cloning technique applied to animals, the technique’s imperfection and the low success rate it was felt that the technique should not be applied on humans, since it could harm the clone child physically or even psychologically. However, with the birth of the human clone there are fears that the child may develop abnormalities just as many animal clones had developed after taking birth.