Peter Michaelis 1704435 108834516 2007-02-17T13:31:33Z RussBot 279219 Robot-assisted fixing links to disambiguation page ([[WP:DPL|you can help!]]) Segregation '''Peter Michaelis''' was a German plant [[geneticist]] who focused most of his research on cytoplasm [[inheritance]] and [[Separation process|segregation]]. Most of Michaelis work was carried out during the period from 1940's to 1970's at the [[Max Planck Institute for Plant Breeding Research]] in [[Köln]]/Vogelsang. == Research == Michaelis worked primarily on the inheritance and segregation of cytoplasmic mutations in ''[[Epilobium]]'', a genus related to ''Oenothera''. He calculated in 1955/1956 the statistical probability of the segregation of two different types of plastids under different conditions. With further research Michaelis concluded that segregation of a mutant [[plastid]] could be the only cause of the observed [[variegation]] in the species. After this Michaelis examined thirty cases of plastid variegation where no mixed [[cell (biology)|cells]] were found. He proposed that mutant and non-mutant plastids were still segregating in early [[mitotic]] divisions. He suggested two possible ways the plastid could influence one-another: (1) The mutant plastid might manufacture a substance that damaged the normal plastids during the maturation process. (2) The normal plastid might manufacture a substance that would allow the mutant form to develop normally. Theory predicted that the two types could be distinguished clearly by an examination of the distribution of mutant and normal cells. Michealis found clear examples of both types of mutation in his material and published his work in 1956. Michaelis firmly believed in complex unity in the cytoplasm, but he rejected simplistic notions such as the plasma gene or that the cause of cytoplasmic inheritance was solely due to plastids and mitochondria. == Summary == Peter Michaelis's work contributed largely to the development and understanding of organelle inheritance in ''Epilobium'' and other plants with two or more chloroplasts per cell. == References == *Michaelis, P ('''1951''') Interactions between genes and cytoplasm in Epilobium. Cold Spring Harb Symp Quant Biol. '''16''':121-129. *Michaelis, P ('''1954''') Cytoplasmic inheritance in Epilobium and its theoretical significance. Adv Genet '''6''':288–402. *Michaelis, P ('''1959''') Cytoplasmic inheritance and the segregation of plasmagenes. X. International Congr. Genet. I. 375-385 *Michaelis, P ('''1966''') The proof of cytoplasmic inheritance in Epilobium (a historical survey as an example for the necessary proceeding). Nucleus '''9''':1-16 *Michaelis, P ('''1971''') The investigation of plasmone segregation by the pattern-analysis. Nucleus '''10''': 1-14 ==External links== *[http://www.mpg.de www.mpg.de] *[http://www.mpiz-koeln.mpg.de www.mpiz-koeln.mpg.de] [[Category:Geneticists|Michaelis, P]]