Dolly the sheep was cloned by means of:
a. applying an electric current to an egg and sperm in a laboratory.
b. taking an embryo from one sheep and implanting it in another.
c. taking a cell from an adult sheep and fusing it with a sheep egg that had its DNA removed.
d. inserting new genes into an existing mammary cell.
e. getting sperm to fuse with egg outside a living sheep.
Adv.
Dolly, the sheep was cloned by means of taking a cell from an adult sheep and fusing it with a sheep egg that has its DNA (deoxyribonucleic acid) removed. A cell was taken from white sheep and allowed to multiply in vitro. An egg was isolated from black-faced sheep and nucleus was removed with the help of a micropipette. A donor cell was selected from the cells, which were allowed to multiply.
Then, the nucleus removed egg cell and the donor cells were placed besides one another and electric shock was applied to egg cell. The electric current triggered fusion of egg cell and the donor cell and the DNA of the donor cell were incorporated in the fused cell. The fused cell developed into embryo and after a period of incubation, it was implanted into a surrogate sheep. At the end of pregnancy, Dolly was born. Dolly was the first mammal to be cloned.
Hence, the correct option is (c) taking a cell from adult sheep and fusing it with a sheep egg that had its DNA removed.