Dec 22, 2009
In 1953 American biologist James Dewy Watson (1928– ) and British biologist Francis Crick (1916– ) developed a model of the structure of DNA (deoxyribonucleic acid). DNA is found in the nucleus of each cell and is responsible for the passing of genetic traits from parents to children. Cells in the human body have forty-six chromosomes, arranged in twenty-three pairs: children inherit half a set of chromosomes from each parent. Each person has ten to twenty billion miles of DNA in his or her cells (there are trillions of cells in a human body). To produce a double-helix model of DNA, Watson and Crick worked with data gathered by Irish biophysicist Maurice Wilkins (1916– ) and with X-ray diffraction photographs by British chemist Rosalind Franklin (1920–1958). The double helix looks like a spiral ladder in which each rung consists of two pairs of chemicals. Further...
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