Klonen van Dolly het schaap

Reproductive cloning is a technique of producing a genetically identical copy — a clone — of a multicellular organism.

The first-ever mammal produced using reproductive cloning was a sheep.

In this experiment, mammary gland cells isolated from an adult Finn Dorset sheep were cultured on media.

After a few cycles of cell division, the cultured cells were deprived of serum nutrients to arrest them in the G0 phase of the cell cycle.

Meanwhile, an egg from a Scottish blackface sheep was enucleated.

Next, the cultured mammary gland cells were fused with the enucleated eggs using brief electric pulses.

The electric pulses also stimulated cell division in the fused cell, generating a blastocyst — an early-stage embryo.

The blastocyst was then implanted into a surrogate Scottish blackface sheep, where it developed into a fetus.

Five months later, a healthy lamb named Dolly was born that shared genetic and morphological features with a Finn Dorset sheep.