Barbara McClintock and Genetic Transposition

Over fifty years ago, Barbara McClintock, working at the Cold Sping Harbor Laboratories on Long Island, New York, was studying the genetics of corn (Zea mays). Working with corn kernels (each of which is an embryonic corn plant), she was performing genetic analyses of color differences and other variations, similar to those carried out in Morgan's laboratory with Drosophila. In the course of these studies, she encountered instances of unexplained sudden gene inactivation. On the basis of mapping and cytological studies, she was able to deduce that these changes in gene function were not due to mutations, but rather were a consequence of the movement of genetic elements—"controlling elements", she called them—from place to place on the chromosome. She reported that these elements actually "jumped" from one site to another on a chromosome and even from one chromosome to another.

Her findings, first published in 1951, were largely ignored, another odd traveler's tale that did not fit into the scheme of things as then understood. "Fiercely independent, beholden to no one", in the words of James Watson, she stubbornly pursued her research, sometimes working without pay. "It was fun", she is reported to have said, "I could hardly wait to get up in the morning".

In the 1980s, with the discovery of a host of movable genetic elements, McClintock has received a barrage of accolades. In 1981, at the age of 79, she was given eight separate awards, including a lifetime grant, and was hailed as a scientific prophet. In 1983, she became a Nobel laureate.

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