Chromosome Structure, Salivary Glands

by Science Source

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Chromosome Structure, Salivary Glands

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Science Source

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Microscopic image of the chromosome structure in the salivary glands of sciara taken by Barbara McClintock in 1934. Throughout her long and distinguished career, Barbara McClintock's work focused on the genetics of maize and, in particular, the relationship between plant reproduction and subsequent mutation. Beginning in the late 1920s, she studied how genes in chromosomes could "move" during the breeding of maize plants. She did groundbreaking research on this phenomenon, where she determined the physical correlate of genetic crossing-over. Later, during the 1940s and 1950s, McClintock showed how certain genes were responsible for turning on or off physical characteristics, such as the color of leaves or individual corn kernels. She developed theories to explain the suppression or expression of genetic information from one generation of maize plants to the next that defied the common wisdom of molecular biology prevalent during the 1950s. After encountering some skepticism about her research and its implications, she refrained from publishing her data in professional journals and only shared her research with a small circle of loyal colleagues. In 1957, McClintock received funding from the National Science Foundation and the Rockefeller Foundation to study different varieties, or races, of maize in South and Central America. In the early 1960s, she traveled extensively, collected maize samples that demonstrated interesting evolutionary characteristics, and mentored junior scientists and young graduate students in maize genetics. McClintock and her colleagues spent two decades assembling data on differences in South American maize, which were finally published in 1981 as The Chromosomal Constitution of Races of Maize. McClintock was recognized throughout her career as one of the most distinguished scientists of the 20th century. In 1944, she became the third woman elected to the National Academy of Sciences. She was the first woman to become president of the Genetic

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March 7th, 2013

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