Genetics => maize, jumping genes

Barbara McClintock was an American scientist and cytogeneticist renowned for her groundbreaking work in genetics, particularly her discovery of mobile genetic elements, or ‘jumping genes’.

Born in 1902, in Connecticut, Barbara McClintock earned her PhD in botany from Cornell University in 1927, where she began her lifelong research on maize (corn) cytogenetics. McClintock developed techniques to visualize maize chromosomes, becoming the first to identify all ten maize chromosomes in 1929.

Her early work included demonstrating the physical basis of genetic recombination through chromosomal crossover during meiosis, a discovery she made alongside Harriet Creighton in 1931, providing the first experimental proof that genes are physically located on chromosomes.

She discovered “jumping genes” by studying the colorful patterns on maize kernels, where the movement of genetic elements caused patches of different colors, such as purple and white, to appear in a mosaic pattern on the same ear of corn. She deduced that these color changes were due to segments of DNA, which she called “controlling elements”, physically moving from one location to another on a chromosome.

This groundbreaking work, which challenged the then-prevailing view of genes as static, was initially met with skepticism and even hostility from the scientific community, leading her to cease publishing her findings in 1953. Despite this, McClintock remained confident in her findings, stating, “It didn’t bother me, I just knew I was right”.

Advances in molecular biology in the 1960s and 1970s confirmed her theories, and her work became foundational to modern genetics, genetic engineering, and our understanding of evolutionary biology.

McClintock was elected to the National Academy of Sciences in 1944 and became the first female president of the Genetics Society of America in 1945.

In recognition of her contributions, McClintock was, amongst numerous other honors, awarded the Nobel Prize in Physiology or Medicine in 1983, becoming the only woman to receive an unshared Nobel Prize in that category.

Barbara McClintock spent much of her career at the Carnegie Institution of Washington’s Cold Spring Harbor Laboratory, where she worked until her retirement in 1967.

She died in 1992, in Huntington, New York, at the age of 90.