I’m sure you have watched at least one movie or read at least one book where a character gets cloned, leading to confusion and conflict. Maybe you yourself have wondered what it would be like to have a clone of yourself running around? Either way, cloning has been a dream for humanity. But this dream became a reality when the first mammal was ever cloned to create Dolly the sheep.

How was Dolly created?

To understand how Dolly was cloned, we must examine how reproductive cells work. Both the sperm and egg contain genes. They combine and the egg is fertilized. The genes from the sperm and from the egg are mixed together and then the fertilized egg starts rapidly dividing until a new organism is created.

To create a clone, the “mixing” of the sperm and egg’s genes must be stopped. But how could this be done? The only way was to remove the sperm entirely.

A batch of cells from the sheep to be cloned was taken from the sheep’s udder. The cells were modified into cells that could later be specialized (skin cells, lung cells, etc.) Another sheep was taken (a different breed of sheep) and an egg was removed. The egg was enucleated (the nucleus was removed), causing the cell to not have any DNA or genes in it. The two cells from the two sheep were combined in a way that emulated the sperm attaching to the egg. Now the resulting sheep will only have the DNA from the sheep to be cloned, causing the resulting sheep to be identical to the original sheep. The egg was now placed in a third sheep to mature and turn into a baby sheep. When the baby sheep was born, it was identical to the original sheep and was effectively a clone of the original sheep. This sheep was called Dolly.