John Gurdon. Does that name mean anything to you? If it doesn't, and you call yourself a biologist, stop now. I saw a job vacancy at the local Tesco Metro. Anyway, John Gurdon is a legend in the world of biology. He started his research on the African clawed toad, Xenopus laevis, to determine whether tissue cells from an adult toad still contained all the genetic material they started with as a blastocyst, or whether they had 'lost' some of this DNA as the cells became more specialised. He did this using the SCNT process (Somatic Cell Nuclear Transfer for the uninitiated), where he transplanted a nucleus from a somatic cell of an adult toad into an enucleated egg cell, which is then given an electric shock, to stimulate mitosis, and the cells are transplanted into a surrogate mother. Gurdon then kept the resulting eggs in a suitably controlled environment. The nucleus from the adult toad somatic cell was relatively unsuccessful at producing tadpoles, however this was irrelevant. He had proved that, genes are not permanently lost during cell differentiation, they were just deactivated. Putting the nucleus in the right environment, like an egg cell, allowed the cell to move back up Waddington's landscape of differentiation and, if not entirely successfully, reactivate the genes required for blastocyst development. This means the cell was essentially made pluripotent, and whatever was 'silencing' the genes in a differentiated cell, was 'wiped off' in the enucleated egg's cytoplasm. Although he was oblivious to it at the time, Gurdon's work was the dawn of a new age for genetics. The age of Epigenetics.
To be continued... (the suspense though!)
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