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Why was Dolly the sheep important in the history of animal cloning?

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Rows of genetically modified barley plants grow in an outdoor test plot in Germany, with a yellow marker labeled 3 and protective netting overhead. — genetically modified organism Genetically modified crops are assessed for their impact on environmental factors such as soil quality.

Dolly the sheep, born in 1996, was a landmark in biological history because she was the first clone of an adult mammal. Her creation by Ian Wilmut and his team at the Roslin Institute fundamentally challenged the long-held scientific assumption that cell differentiation in adult cells was irreversible.12

Before Dolly, it was believed that adult cells lost their totipotency—the ability to develop into any cell type required for a complete organism. By using a technique later known as somatic cell nuclear transfer (SCNT), researchers successfully reprogrammed the nucleus of a fully differentiated mammary gland cell to create a viable, living lamb.23

Dolly’s birth proved that the genetic material of an adult cell could be reset to an embryonic state, opening a new era of scientific research. While this breakthrough offered potential applications in livestock farming and medicine, it also ignited significant ethical debates regarding the risks of birth defects and the potential for human cloning, which Wilmut and the scientific community have largely deemed impractical and ethically fraught.231