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| 1. Cloning and Genetic Engineering Defined
3. Current Applications Of Genetic Engineering 4. Cloning Techniques A - Cells
5. Cloning Techniques B - Animals |
Roslin’s ReCreation 20 years after Gurdon’s frog experiment, Dr. Keith Campbell, a scientist working for Dr. Wilmut at the Roslin Institute, came up with the idea that cloning was somehow linked to the cell cycle. The common theory was that to make a clone you needed to do nuclear transfer on a fast-dividing cell, however, there had been no successful experiments yet. Dr. Campell looked at it from a different angle, deciding that maybe a quiescent cell would work better. That’s where the sheep came in. Roslin’s scientists used sheep because they already had experience working with them. Previously, in partnership with Pharmaceutical Proteins Limited Therapeutics (otherwise known as PPL Therapeutics), they had created transgenic sheep for medical research. Transgenic sheep are sheep that have human genes. The first transgenic livestock was "created" in 1985 by Ralph Brinster (see timeline). For the donor nucleus they used cells from an adult sheep’s mammary (breast) glands. The cells were placed into tissue cultures to grow. A tissue culture is an artificial environment commonly used in laboratories to grow large numbers of cells, meanwhile giving the scientist complete control over the cells. Dr. Campbell made the cells become quiescent by starving them of the nutrients they needed to grow and divide.
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