Barbara McClintock was an early pioneer in the study of maize (corn) genetics. She visualized chromosomes in corn cells using microscopy, and she observed color patterns of kernels (seeds) that did not always conform to expectations of typical inheritance patterns.
McClintock's work in the 1930s was instrumental in advancing the field of
, the study of chromosome structure and function.
In the 1940s, based on her study of unusual inheritance patterns she proposed that some DNA can change its physical position, and these moveable DNA sequences are now known as