Dolly the sheep was cloned using somatic cell nuclear transfer (SCNT).

What that process means

  • In somatic cell nuclear transfer, the nucleus from a body (somatic) cell of an adult animal is removed.
  • This nucleus is inserted into an egg cell whose own nucleus has been removed, and the reconstructed egg is stimulated to divide and develop into an embryo.

How it applied to Dolly

  • Researchers took a nucleus from a mammary gland cell of an adult Finn Dorset ewe and fused it with an enucleated egg cell from another sheep.
  • The resulting embryo was implanted into a surrogate mother, and the lamb born—Dolly—was a genetic clone of the Finn Dorset donor.

TL;DR: The process used was somatic cell nuclear transfer (nuclear transplantation using an adult somatic cell nucleus).