From the age of three until she began school, McClintock lived with an aunt and uncle in Brooklyn, New York, in order to reduce the financial burden on her parents while her father established his medical practice.

This group brought together plant breeders and cytologists, and included Marcus Rhoades, future Nobel laureate George Beadle, and Harriet Creighton.

[23] McClintock's breakthrough publications, and support from her colleagues, led to her being awarded several postdoctoral fellowships from the National Research Council.

Exposure to X-rays can increase the rate of mutation above the natural background level, making it a powerful research tool for genetics.

She showed that the loss of ring-chromosomes at meiosis caused variegation in maize foliage in generations subsequent to irradiation resulting from chromosomal deletion.

[7][33] She left Germany early amidst mounting political tension in Europe, returned to Cornell, but found that the university would not hire a woman professor.

The broken ends were rejoined in the interphase of the next mitosis, and the cycle was repeated, causing massive mutation, which she could detect as variegation in the endosperm.

In December 1941, she was offered a temporary research position by Milislav Demerec, the newly appointed acting director of the Carnegie Institution of Washington's Department of Genetics Cold Spring Harbor Laboratory; McClintock accepted his invitation despite her qualms and became a permanent member of the staff in 1943 .

After her year-long temporary appointment, McClintock accepted a full-time research position at Cold Spring Harbor Laboratory.

[47][48][49][50] She observed the effects of the transposition of Ac and Ds by the changing patterns of coloration in maize kernels over generations of controlled crosses, and described the relationship between the two loci through intricate microscopic analysis.

[4] In 1950, she reported her work on Ac/Ds and her ideas about gene regulation in a paper entitled "The origin and behavior of mutable loci in maize" published in the journal Proceedings of the National Academy of Sciences.

In summer 1951, she reported her work on the origin and behavior of mutable loci in maize at the annual symposium at Cold Spring Harbor Laboratory, presenting a paper of the same name.

[4][55][50] Her work on controlling elements and gene regulation was conceptually difficult and was not immediately understood or accepted by her contemporaries; she described the reception of her research as "puzzlement, even hostility".

[58] Based on the reactions of other scientists to her work, McClintock felt she risked alienating the scientific mainstream, and from 1953 was forced to stop publishing accounts of her research on controlling elements.

[60][32] After extensive work in the 1960s and 1970s, McClintock and her collaborators published the seminal study The Chromosomal Constitution of Races of Maize, leaving their mark on paleobotany, ethnobotany, and evolutionary biology.

[61] See Kass (2024, Chapter 9), for extensive details of McClintock's research and influence on the cytogenetics of the Races of Maize in Mexico and South America.

[42] This honor allowed her to continue working with graduate students and colleagues in the Cold Spring Harbor Laboratory as scientist emerita; she lived in the town.

It is now equally painful to recognize the fixity of assumptions that many persons hold on the nature of controlling elements in maize and the manners of their operation.

[63]The importance of McClintock's contributions was revealed in the 1960s, when the work of French geneticists François Jacob and Jacques Monod described the genetic regulation of the lac operon, a concept she had demonstrated with Ac/Ds in 1951.

Following Jacob and Monod's 1961 Journal of Molecular Biology paper "Genetic regulatory mechanisms in the synthesis of proteins", McClintock wrote an article for American Naturalist comparing the lac operon and her work on controlling elements in maize.

[64][58] Even late in the twentieth century, McClintock's contribution to biology was still not widely acknowledged as amounting to the discovery of genetic regulation.

In 1982, she was awarded the Louisa Gross Horwitz Prize from Columbia University for her research in the "evolution of genetic information and the control of its expression.

Postal Service issued a panel of first-class stamps honoring Barbara McClintock, along with Richard Feynman, Josiah Willard Gibbs, and John von Neumann.

[83] McClintock spent her later years, post Nobel Prize, as a key leader and researcher in the field at Cold Spring Harbor Laboratory on Long Island, New York.

Keller argued that because McClintock felt like an outsider within her field, (in part, because of her sex) she was able to look at her scientific subjects from a perspective different from the dominant one, leading to several important insights.

[86] In addition, geneticist Lotte Auerbach recounted that Joshua Lederberg returned from a visit to McClintock's lab with the remark: 'By God, that woman is either crazy or a genius.'

'"[87][88] In 2001, a second biography by science historian Nathaniel C. Comfort's The Tangled Field: Barbara McClintock's Search for the Patterns of Genetic Control challenged this narrative.

A recent biography for young adults by Naomi Pasachoff, Barbara McClintock, Genius of Genetics, provides a new perspective, based on the current literature.

[92][93] Some of McClintock's personality and scientific achievements were referred to in Jeffrey Eugenides's 2011 novel The Marriage Plot, which tells the story of a yeast geneticist named Leonard who has bipolar disorder.

[94] Judith Pratt wrote a play about McClintock, called MAIZE, which was read at Artemesia Theatre in Chicago in 2015, and was produced in Ithaca NY, the home of Cornell University, in February–March 2018.