Peter Michaelis
Encyclopedia
Peter Michaelis was a German plant geneticist
who focused most of his research on cytoplasm inheritance
and 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.
, 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 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.
Geneticist
A geneticist is a biologist who studies genetics, the science of genes, heredity, and variation of organisms. A geneticist can be employed as a researcher or lecturer. Some geneticists perform experiments and analyze data to interpret the inheritance of skills. A geneticist is also a Consultant or...
who focused most of his research on cytoplasm inheritance
Inheritance
Inheritance is the practice of passing on property, titles, debts, rights and obligations upon the death of an individual. It has long played an important role in human societies...
and segregation
Separation process
In chemistry and chemical engineering, a separation process, or simply a separation, is any mass transfer process used to convert a mixture of substances into two or more distinct product mixtures, at least one of which is enriched in one or more of the mixture's constituents. In some cases, a...
. 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
Max Planck Institute for Plant Breeding Research
The Max Planck Institute for Plant Breeding Research is located in Cologne, Germany. The institute was founded as part of the Kaiser Wilhelm Society as the Kaiser Wilhelm Institute for Plant Breeding Research in 1928 in Müncheberg, midway between Berlin and the German-Polish border...
in Köln
KOLN
KOLN, digital channel 10, is the CBS affiliate in Lincoln, Nebraska. It operates a satellite station, KGIN, on digital channel 11 in Grand Island. KGIN repeats all KOLN programming, but airs separate commercials...
/Vogelsang.
Research
Michaelis worked primarily on the inheritance and segregation of cytoplasmic mutations in EpilobiumEpilobium
Epilobium is a genus in the family Onagraceae, containing about 160-200 species of flowering plants with a worldwide distribution. They are generally abundant in the subarctic, temperate and subantarctic regions, whereas in the subtropics and tropics they are restricted to the cool montane biomes,...
, 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
Plastid
Plastids are major organelles found in the cells of plants and algae. Plastids are the site of manufacture and storage of important chemical compounds used by the cell...
could be the only cause of the observed variegation
Variegation
Variegation is the appearance of differently coloured zones in the leaves, and sometimes the stems, of plants. This may be due to a number of causes...
in the species.
After this Michaelis examined thirty cases of plastid variegation where no mixed cells
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
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.