Dolly was the most famous sheep in history. Her parents were the nucleus of a skin cell scratched from the udder of a six-year-old sheep and an unnamed ewe’s egg, their bed a Petri dish. She was the first mammal to be cloned from an adult cell, her inventors having succeeded in winding back the developmental clock that commits indeterminate cells to becoming skin, heart, bone, nerves or any of the hundreds of different kinds of tissue. Dolly’s birth shattered long-held beliefs in molecular biology. It also sparked the moral imaginations of millions who agonized that humans would be next.
Her birth put genetics into the newspapers. Soon scientists—often ignored by the media—were stars. They were cloning cats and pigs, growing human stem cells from early human embryos, discovering the genes and enzymes that keep aging cells from dying and cancer cells from multiplying, and spelling out the long strings of code that comprise genomes. Long the underdog to nuclear...
Hannah Hoag is a science journalist in Montreal. She earned a graduate degree in biology from McGill University, where she studied mouse models of human genetic disease before changing course to write about science and medicine.
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