Final answer:
Barbara McClintock's discovery of transposons, or 'jumping genes', in maize genetics provided a new understanding of genetic regulation, as these DNA elements can move within the genome.
Step-by-step explanation:
Barbara McClintock's pioneering work in maize genetics led her to discover a phenomenon that would revolutionize our understanding of genetic regulation and inheritance. While studying the pigmentation patterns of maize kernels, she identified transposons, also known as 'jumping genes', which are sequences of DNA capable of moving to different positions within the genome of a single cell. This discovery was initially met with skepticism, as the idea of mobile genetic elements was very unconventional at the time. However, McClintock's results were substantiated by later findings in other organisms such as bacteria and fruit flies.
Transposons are now known to be composed of DNA that has the ability to shift from one genomic location to another. They can impact gene expression and contribute to genetic diversity, which is often observed as variations in traits, such as pigmentation in maize kernels. McClintock's detection of transposons and her insights into gene regulation led to a deeper understanding of hereditary mechanisms and earned her a Nobel Prize in Physiology or Medicine in 1983.