In 1996, a sheep named Dolly was created by cloning at Roslin Institute, a British government laboratory operated by the Biotechnology and Biological Sciences Research Council (BBSRC). The genetic material came from a body cell (not a fertilized egg) provided by another laboratory, Pharmaceutical Proteins, Ltd. (PPL), not affiliated with Roslin. The researchers removed the nucleus of Dolly's mother's egg, leaving an enucleated cell (a cytoplast, i.e., a cell without a nucleus). They also removed the donor nucleus (kartoplast) from the body cell which had been sent to them by PPL. They inserted the donor nucleus into the enucleated cell. After a normal gestation period, Dolly was born. Dolly was observed to be a Finn-Dorset lamb, which has a white face, although her mother was a Scottish Blackface sheep. This indicated that her genetic code was that of the white faced strain which had contributed the body cell. Dolly wasn't the first mammal ever to be cloned, nor even the first cloned sheep. In 1995 Wilmut and Campbell had successfuly produced two sheep named Megan and Morag by nuclear transfer, but the donor nuclei had been removed from fertilized eggs. Dolly was the first mammal to be produced by transfer of a nucleus from a body cell (they used a mammary gland cell). Out of 277 reconstructed embryos produced on that occasion, Dolly was the only success. The rapid pace of technology which we have observed in electronics and space exploration in the last half of the 20th century has occurred in biotechnology as well. In the 1950s, Robert Briggs, a scientist at the Institute of Cancer Research in Philadelphia, took an interest in conducting DNA experiments. He teamed up with Thomas J. King of New York University, and they undertook the first work on cell nucleus transplant in frogs. The tadpoles produced by Briggs and King, in the words of Wilmut and Campbell, "... introduced -- if any single event can be said to have done so -- the modern clone age." [Page 77] In the 1960s, researchers learned how to fuse two cells by using a virus, the Sendai Virus, to open their membranes. The membranes then fuse into one membrane, and two cells have become one cell. In the 1970s scientists invented the electrofusion technique, which opens and fuses the membranes with an electrical current, superior to the Sendai Virus method. In the 1970s, Ian Wilmut worked on a project a Cambridge that produced Frostie, the first calf born from a frozen embryo. The first success in cytopreservation, that is, freezing cells and then restoring them to life, had occurred in 1953. Today we read news reports of lawsuits and court orders related to frozen human eggs or frozen sperm.
In the 1970s, artificial insemination (AI), which has already been performed for many years with animals, became a practical option for human couples, one-eighth of whom have such reproductive problems as low sperm counts or blocked fallopian tubes. In 1978, the first person conceived by in vitro fertilization (IVF) was born in England. The press called Louise Joy Brown a "test tube baby." In 1980, German embryologist Karl Illmensee and American embryologist Peter Hoppe produced three cloned mice by nuclear transfer, performing the microsurgery with a pipette. (Illmensee was already famous for his research in the 1960s on the genetics of fruit flies. Genetics researchers often experiment with fruit flies because their life cycle is so short that numeorus generations can be observed in the laboratory.) In 1990, genetic engineering (not cloning) produced Tracy, a sheep implanted with a human gene that caused her milk to contain the enzyme AZT. This enzyme is normally found only in human milk. The enzyme is needed in the manufacture of medicine to treat cystic fibrosis in humans. Dolly is another success in this exponential climb of biotechnology. Several children suffering from cystic fibrosis decided to express their approval of biotechnology by visiting Dolly in her nursery, and pose for photos of them petting her (one of these photos is included in the book's insert of illustrations). After Dolly, Polly was born in 1997. Polly was the first sheep to be both cloned and genetically transformed. What will occur next? Campbell's personal goal is, "I want to be the first to clone a pig." [page 300] Some researchers view Dolly and Polly a stepping stones toward a future production of cloned cattle which will have the genetic makeup permitting optimum use of their diets, resulting in more milk production. Some scientists are hoping to create a woolly mammoth, an extinct species, by using a cell from the frozen body of a woolly mammoth that was found preserved in the permafrost of Siberia, although the animal died 20,000 years ago. Many people speculate about the possibility of human cloning. The issue leads to ethical and religious debates and heated arguments. Cloning people is the title and topic of Chapter 13. The wider field of the ethics and social responsibility of scientists is considered. "We want to offer our personal opinions on human cloning, not because we assume any particular moral authority, but in the spirit of throwing pebbles into the pool of discussion." [268] The authors explain that their own opinions as scientists should not carry any more weight than the opinions of other citizens, because this is implicit in the meaning of a democratic society. Therefore, this chapter is a "look at the factual issues." [268] If you have an interest in science and technology, you will find this book fascinating. It is, furthermore, the sort of book which will benefit you if you wish to discuss modern biotechnology intelligently.
Reviewed by Mike Lepore for crimsonbird.com [ email ]
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