Researched
Nuclear Transfer (Cloned Frogs)
John Gurdon swapped the nucleus of a frog egg for one from a tadpole's body cell and still raised tadpoles, showing that a specialised cell keeps all its genes and can be reset.
Open in the interactive tree →In 1952 Robert Briggs and Thomas King in the US had moved nuclei from early embryo cells into frog eggs. From 1958 John Gurdon at Oxford did the same with nuclei from body cells of Xenopus tadpoles, and a 1962 paper used cells from the lining of a tadpole's gut. The result showed that a specialised cell differs from an egg in which genes are switched on, not in which genes it holds; it led to Dolly the sheep in 1996 and to Yamanaka's 2006 reprogramming of adult cells, and Gurdon and Yamanaka shared the 2012 Nobel Prize in Medicine.
Prerequisites
- Cell Theory1838Every cell has a nucleus and comes from another cell.
- Chromosome Theory of Heredity1915Genes sit on the chromosomes inside the nucleus.
Unlocks
- Cloning (Dolly the Sheep)1996Dolly was made with the same nuclear transfer idea, using an adult sheep cell.
- Induced Pluripotent Stem Cells2006Gurdon showed a specialised cell's nucleus can be reset; he shared the 2012 Nobel Prize with Yamanaka.