Barbara McClintock

The outstanding scientist is the eponym for a laboratory in Carnegie University of Wahington and a street in a science park in Berlin.

On June 16, 1902, Eleanor McClintock aka Barbara McClintock, was born to parents Thomas Henry and Sara Handy McClintock in the capital city of Connecticut.

Eleanor who was rechristened as Barbara spent most of her early childhood with her relatives in New York, as her father a practising physician toiled to establish his business. In 1908, she was enrolled at the ‘Erasmus Hall High School’ when the family shifted base to Brooklyn.

The inquisitive and independent kid realised her attraction towards science and pursued higher education at the ‘Cornell University’, after completing high school in 1919.

At the ‘College of Agriculture’, affiliated to the ‘Cornell University’ she made her first tryst with genetics. Encouraged by eminent botanist Claude B. Hutchinson she took up the subject as a discipline, after earning a bachelor’s degree in Botany in 1923.

Two years later she completed her post-graduation and was awarded an MA in Botany. For her doctoral dissertation she involved in research work involving the structure and functionality of chromosomes in maize. She worked on her thesis under the guidance of botanists Lowell Fitz Randolph and Lester W. Sharp and was awarded a Ph.D. in 1927.

The budding scientist continued her study of chromosomal behaviour in maize during meiosis and devised a technique, using carmine staining, which allowed researchers to observe chromosomes under the microscopes.

In the years 1930-31, she made a major breakthrough by explaining the concept of chromosomal cross-over as observed in homologous chromosomes during meiosis. Along with botanist Harriet Creighton she established scientific proof of the hypothesis that chromosomal cross over was responsible recombination of genetic traits.

The duo published a paper titled ‘A Correlation of Cytological and Genetical Crossing-over in Zea mays’ explaining their works.

Also in 1931, she created the first ever genetic map for maize representing the arrangement of three genes on maize chromosome 9. In further expansion of their work on chromosomal crossover, they demonstrated that the phenomenon occurs not only in homologous chromosomes but is also evident in sister chromatids.

She then worked in association with Lewis Stadler in Missouri during 1931-32 and used X-rays as mutagen for her studies on genetics. She studied the effects of radiation on chromosomal behaviour and explained the arrangement of DNA sequence on chromosome 6 of maize which is necessary for formation of a nucleolus.

Barbara McClintock has made many significant contributions in the sphere of cytogenetics but her work on the controlling units and gene regulation paved way for many future discoveries. The revolutionary discoveries regarding the transposable elements on the DNA which lead to genetic mutation, earned her a Nobel Prize in Medicine or Physiology.