Mapping and seeing: Barbara McClintock and the linking of genetics and cytology in maize genetics, 1928–35
In April 1929, Rollins A. Emerson, head of the Plant Breeding Department at Cornell University, sent a summary of linkage data in maize to his colleagues (Emerson 1929). He had gathered maize geneticists in his hotel room in late 1928 at the AAAS winter science meetings in New York and formalized a cooperative group that he had informally initiated around 1920. In this first communication of what later became the “Maize Genetics Cooperation News Letter” he listed 10 linkage groups and gave a provisional genetic map for each of them. These maps were rather vague and the “rainbows” (Figure 5.1) indicated that much work needed to be done. All of the approximately 60 references he cited were based purely on the analysis of genetic crosses (Emerson 1929).