Barbara McClintock (1902-1992) was born in Hartford, Connecticut. She completed her undergraduate course in genetics at Cornell's College of Agriculture in 1919. The botany department was then involved in the study of maize genetics work. She found she could identify individual maize chromosomes under the microscope, and the 10 chromosomes of maize led to plant breeding experiments with chromosomal analysis. Within a few weeks, Barbara applied new staining techniques, identified the part of the embryo most suitable for cytological studies, and launched the new science of cytogenetics. McClintock earned her PhD in 1927, and from 1928 to 1935, she continued working with a small committed group of researchers at various institutions.