 In 1957 , McClintock received funding from the National Academy of Sciences to start research on indigenous strains of maize in Central America and South America . She was interested in studying the evolution of maize through chromosomal changes , and being in South America would allow her to work on a larger scale . McClintock explored the chromosomal , morphological , and evolutionary characteristics of various races of maize . 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 . 
