Cloning issues in reproduction, science and medicine : a consultation document / Human Genetics Advisory Commission and Human Fertilisation & Embryology Authority.

  • Great Britain. Human Genetics Advisory Commission.
Date:
1998
Catalogue details

Licence: Open Government Licence

Credit: Cloning issues in reproduction, science and medicine : a consultation document / Human Genetics Advisory Commission and Human Fertilisation & Embryology Authority. Source: Wellcome Collection.

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    and could perhaps lead to increased incidence of diseases such as Cancer. Dolly appears to be a normal healthy animal and her development will continue to be closely monitored as she grows older. There have also been major developments since Dolly’s announcement. News of “Polly” was released by PPL Therapeutics in July 1997. This project is part of a PPL programme which aims to develop technology which will allow large amounts of proteins of therapeutic value to humans to be produced economically. In creating Polly, PPL for the first time combined existing techniques of nuclear replacement and transgenics. The nuclei in cultured fibroblast cells from a female sheep fetus were first modified through the addition of the human gene for factor IX (a blood clotting protein), by a process known as transfection. The modified nucleus was then introduced into the sheep’s egg from which the DNA had been removed - the nuclear replacement step. In this way, Polly has been transgenically modified to enable her to produce therapeutic human proteins in her milk, and was created using nuclear replacement technology. The ability to clone transgenic sheep offers the prospect of the economically viable generation of flocks of sheep which are of particular benefit to humans. Nuclear replacement has also been used for cloning in various mammalian species (mice, rabbits, cattle), but until recently only nuclei taken from very early embryos were effective, and development was often abnormal, for reasons that are not fully understood. Recently, in the United States, ABS Global Inc. have cloned a Holstein Bull, Gene, by transfer of a fibroblast nucleus from a male Holstein fetus. This was the first calf to be born from a non-embryo-derived cell. 30