Question

Dolly, a female domestic sheep, was the first successful clone derived from an adult mammal cell. Dolly showed that genes in the nucleus of a mature differentiated somatic cell are still capable of reverting to an embryonic ______________ state

Answer 1

Dolly was a first mammal cloned from an adult somatic cell, she was a domestic sheep, using the process of nuclear transfer. Dolly showed that genes in the nucleus of such a mature differentiated somatic cell are still capable of reverting to an embryonic totipotent state.
The totipotent cell is a cell that can form all the cell types in the body, it has an ability of a single cell to produce and divide all of the differentiated cells in an organism.

Answer 2

Dolly was a first cloned sheep, derived from a cell of adult sheep.  The nucleus of the adult female sheep's cell was transferred to a developing egg cell of another female sheep, from which nucleus was removed. Then, resulting cell was implanted in another sheep (surrogate mother) at blastula stage.  

This cell was developed as Dolly and showed that the genes present in differentiated somatic cell of an adult are still capable to revert to an undifferentiated embryonic totipotent state that gives rise to a complete muticellular organism.

Thus, the correct answer to be filled in the blank is 'totipotent.'