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It is named after John Langdon Down, the British doctor who fully described the syndrome in 1866. Some aspects of the condition were described earlier by Jean-Ãtienne Dominique Esquirol in 1838 and Ãdouard SÃ©guin in 1844. In 1957, the genetic cause of Down syndrome, an extra copy of chromosome 21, was discovered.
the museum. The Life of John Wesley Powell. John Wesley Powell was a soldier, scientist, and explorer. He is best known for his daring exploratory trips down the Green and Colorado Rivers in 1869 and 1872, and is credited with leading the first group of white men down the Colorado River through present day Grand Canyon.