other internal cellular organelles (Kappa particles) which had their own DNA were inherited but limited by their distribution in the cytoplasm at the time of cell division. Only progeny from the 'half' of the cell with the mutant organelles inherited those organelles and thus the associated trait. Obviously, most cells had a distribution such that the organelles were in both halves but in cases where the new mutant arose and thus is rare then only those cell with cytoplasm containing the rare form inherited the traits associated with it. It is a mark of his excellence as a scientist that he should have taken the trouble to follow the fate of subsequent generations and so be able to make these observation. It may seem surprising that the clear evidence for non-Mendelian inheritance should have been largely overlooked by the scientific community. It may also be that, as at that time the mechanisms of genetic inheritance in DNA were becoming open to investigation, this example of non-Mendelian inheritance was not of great interest to the scientific community. While non-mendelian inheritance is limited to the cortical structures and to the internal organelles with their own DNAk it does play a major role in some human disorders as well as "handiness" and the left/right orientation of the zygote. Very important factors. Sonneborn as teacher Sonneborn was an innovative teacher. He taught a course entitled Heredity, Evolution and Society that dealt with the science of genetics and the implications that technological advancements in that field held for society. One of his popular lectures involved students enacting the process of protein synthesis during which the genetic code is translated into the sequential addition of amino acids to form a polypeptide. His enthusiasm was infectious, and his lectures inspired students to study protozoa and algae. Personal life Sonneborn married Ruth Meyers in 1929. Though educated as a social worker, she concentrated upon supporting her husband's career. They had two sons: Lee (1929–2004), a mathematician, and David (b. 1934), a biologist. References External links Sonneborn Manuscripts at the Lilly Library Manuscript Collections Foreign Members of the Royal Society 1905 births 1981 deaths American microbiologists Protistologists People from Baltimore Indiana University faculty Baltimore City College alumni Johns Hopkins University alumni Members of the American Philosophical Society