1956: Genetic Mechanisms: Structure and Function, Vol. XXI
Organizer: Milislav Demerec
There is a story that a reader of T. H. Morgan's Embryology and Genetics (published in 19XX) complained that he had been disappointed by the bookhe had expected to find a discussion of the genetic basis of embryological differentiation but the topics were treated separately. Morgan replied that he had written exactly what the title promised: "I talked about embryology and I talked about genetics." This separation of genetics and embryology was still evident in 1956 but as Demerec wrote in the foreword to the Symposium volume, "Recent developments...indicate that we may be on the verge of bridging the gap that now separates genetics and embryology." He hoped to help close that gap by bringing together geneticists interested in gene function with embryologists interested in the genetic control of cell differentiation.
However, the only "recent developments" mentioned by Demerec were on the genetics side of the divide, and the importance of genetics was reflected in the title for the Symposium and its organization. It began at the Chemical Level, and then progressed through the Genic, Chromosomal, Cellular and Developmental Levels. However, only four of the 29 presentations dealt with development.
There were some interesting papers
discussing cell differentiation. For example, King and Briggs gave an extended review of their latest work transplanting nuclei between frog embryos while Wolfgang Beerman described his observations of the puffs, Balbiani rings and lamp-brushes found on Dipteran chromosomes, using them to follow cell differentiation. In the same session, Barbara McClintock described her further work on the Ac/Ds and Spm controlling elements. The printed paper is very abstruse and . There is an interesting touch of controversy in the discussion to Herschel Roman's paper on mutations in yeast. Roman and Lindegren, the founding father of yeast genetics, disagreed over "gene conversion" that was to account for irregular segregation patterns. Roman doubted its existence, and was told by Lindegren that "...he [Roman] has lived for the past five years in error"!
— Jan A. Witkowski