Why was Dolly the sheep an important scientific breakthrough?

Dolly the sheep, born in 1996, was a landmark scientific breakthrough because she was the first clone of an adult mammal.12

Before Dolly, it was widely presumed that cell differentiation—the process by which cells become specialized—was irreversible, meaning adult cells lost the totipotency required to create a complete, viable animal. By successfully using a mammary gland cell from an adult ewe to produce a healthy lamb, researchers at the Roslin Institute proved that adult cells could be reprogrammed to support the development of a new organism.23

This achievement utilized a technique known as somatic cell nuclear transfer (SCNT). While the experiment opened new doors for biotechnology and potential applications in agriculture and medicine, it also ignited significant ethical debates regarding the implications of cloning technology. Scientists, including Ian Wilmut, have emphasized the practical and ethical dangers of the process, noting high rates of developmental failure and birth defects in cloned animals.123