In Loving Memory of Dolly

Dolly, the world's first mammal cloned from an adult somatic cell, was euthanized on February 14, 2003, at the Roslin Institute near Edinburgh, Scotland, after developing a progressive lung disease. She was six years old. Born on July 5, 1996, Dolly was created by scientists Ian Wilmut and Keith Campbell using somatic cell nuclear transfer. A cell was taken from the mammary gland of a six-year-old ewe, and its nucleus was transferred into an enucleated egg cell. Of 277 attempts, Dolly was the sole survivor. She was named after the singer Dolly Parton, a nod to the mammary cell that gave her life. Her birth, announced to the public in February 1997, sent shockwaves through the scientific world and beyond. Dolly became the most famous sheep since the biblical flocks, appearing on magazine covers worldwide and drawing visitors to the Roslin Institute. Dolly lived a relatively normal sheep's life. She grazed, she socialized, and she gave birth to six lambs over three pregnancies — all conceived naturally. But in 2001, she was diagnosed with arthritis at an unusually young age, and in 2003, a CT scan revealed progressive lung disease. The question of whether her premature aging was a consequence of cloning or simply bad luck has never been definitively answered. Her taxidermied remains are on display at the National Museum of Scotland in Edinburgh. Dolly proved that the genetic code of a single adult cell contains all the instructions necessary to build an entire organism. She opened the door to therapeutic cloning, stem cell research, and a future that is still unfolding. She was, in every meaningful sense, one of a kind.