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Walther Flemming (21 April 1843 – 4 August 1905) was a German
biologist A biologist is a scientist who conducts research in biology. Biologists are interested in studying life on Earth, whether it is an individual cell, a multicellular organism, or a community of interacting populations. They usually speciali ...
and a founder of
cytogenetics Cytogenetics is essentially a branch of genetics, but is also a part of cell biology/cytology (a subdivision of human anatomy), that is concerned with how the chromosomes relate to cell behaviour, particularly to their behaviour during mitosis ...
. He was born in Sachsenberg (now part of
Schwerin Schwerin (; Mecklenburgian Low German: ''Swerin''; Latin: ''Suerina'', ''Suerinum'') is the capital and second-largest city of the northeastern German state of Mecklenburg-Vorpommern as well as of the region of Mecklenburg, after Rostock. ...
) as the fifth child and only son of the psychiatrist
Carl Friedrich Flemming Carl Friedrich Flemming (27 December 1799 – 27 January 1880) was a German psychiatrist born in Jüterbog. He was the father of cellular biologist Walther Flemming (1843-1905). After receiving his medical doctorate from Berlin, he worked as an ...
(1799–1880) and his second wife, Auguste Winter. He graduated from the ''Gymnasium der Residenzstadt'', where one of his colleagues and lifelong friends was writer Heinrich Seidel.


Career

Flemming trained in
medicine Medicine is the science and Praxis (process), practice of caring for a patient, managing the diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment, Palliative care, palliation of their injury or disease, and Health promotion ...
at the University of
Prague Prague ( ; cs, Praha ; german: Prag, ; la, Praga) is the capital and largest city in the Czech Republic, and the historical capital of Bohemia. On the Vltava river, Prague is home to about 1.3 million people. The city has a temperate ...
, graduating in 1868. Afterwards, he served in 1870–71 as a military physician in the Franco-Prussian War. From 1873 to 1876 he worked as a teacher at the University of Prague. In 1876 he accepted a post as a professor of
anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its ...
at the University of Kiel. He became the director of the Anatomical Institute and stayed there until his death. With the use of
aniline Aniline is an organic compound with the formula C6 H5 NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine. It is an industrially significant commodity chemical, as well as a versatile start ...
dyes he was able to find a structure which strongly absorbed basophilic dyes, which he named
chromatin Chromatin is a complex of DNA and protein found in eukaryote, eukaryotic cells. The primary function is to package long DNA molecules into more compact, denser structures. This prevents the strands from becoming tangled and also plays important ...
. He identified that chromatin was correlated to threadlike structures in the cell nucleus – the
chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins ar ...
s (meaning ''coloured bodies''), which were named thus later by German anatomist Wilhelm von Waldeyer-Hartz (1841–1923). The Belgian scientist Edouard Van Beneden (1846–1910) had also observed them, independently. The centrosome was discovered jointly by Walther Flemming in 1875 and Edouard Van Beneden in 1876. Flemming investigated the process of
cell division Cell division is the process by which a parent cell divides into two daughter cells. Cell division usually occurs as part of a larger cell cycle in which the cell grows and replicates its chromosome(s) before dividing. In eukaryotes, there ar ...
and the distribution of chromosomes to the daughter nuclei, a process he called
mitosis In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is maint ...
from the Greek word for thread. However, he did not see the splitting into identical halves, the daughter chromatids. He studied mitosis both '' in vivo'' and in stained preparations, using as the source of biological material the fins and
gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they ar ...
s of
salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All ten ...
s. These results were published first in 1878 and in 1882 in the seminal book ''Zellsubstanz, Kern und Zelltheilung'' (1882; Cell substance, nucleus and cell division). On the basis of his discoveries, Flemming surmised for the first time that all cell nuclei came from another predecessor nucleus (he coined the phrase ''omnis nucleus e nucleo'', after Virchow's ''omnis cellula e cellula''). Flemming is also known for his philanthropy. He weekly fed those who were homeless, donating every year, 20% of his salary to homeless shelters. He taught especially young children who were too poor to attend school about mathematics and science. Flemming was unaware of the work of
Gregor Mendel Gregor Johann Mendel, OSA (; cs, Řehoř Jan Mendel; 20 July 1822 – 6 January 1884) was a biologist, meteorologist, mathematician, Augustinian friar and abbot of St. Thomas' Abbey in Brünn (''Brno''), Margraviate of Moravia. Mendel wa ...
(1822–84) on
heredity Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic info ...
, so he did not make the connection between his observations and genetic inheritance. Two decades would pass before the significance of Flemming's work was truly realized with the rediscovery of Mendel's rules.
The Science Channel Science Channel (often simply branded as Science; abbreviated to SCI) is an American pay television channel owned by Warner Bros. Discovery. The channel features programming focusing on science related to wilderness survival, engineering, ...
named Flemming's discovery of mitosis and chromosomes as one of the 100 most important scientific discoveries of all time, and one of the 10 most important discoveries in
cell biology Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living a ...
. Flemming's name is honoured by a medal awarded by the German Society for Cell Biology (Deutsche Gesellschaft für Zellbiologie).


References


Further reading

* * * * * and Reprinted in ''J. Cell Biol.'' 25:581–589 (1965). *Flemming, W. "Zur Kenntniss der Zelle und ihrer Theilungs-Erscheinungen". In: ''Schriften des Naturwissenschaftlichen Vereins für Schleswig-Holstein'' 3 (1878), 23–27. (Reprinted in '')'' * Carlson, E.A. "The Analysis of Mitosis Shifts Attention to the Chromosomes". In: ''Mendel's Legacy. The Origins of Classical Genetics''. p. 24–5, CSHL Press, 2004. .


External links


Walther Flemming Biography
Lasker Labs
Zellsubstanz, Kern und Zelltheilung
Original text of the book, as PDF (In German).
Walter Flemming Medaille
In PDF, in German. * Hardy, P. A., Zacharias, H. (2008): "Walther Flemming und die Mitose: Der Beitrag seiner ersten Kieler Jahre". ''Schr. Naturwiss. Ver. Schlesw.-Holst''. 70, 3–15. Paper about his first description of mitosis. In German. {{DEFAULTSORT:Flemming, Walther 1843 births 1905 deaths People from Schwerin People from the Grand Duchy of Mecklenburg-Schwerin 19th-century German biologists German geneticists Cytogenetics Members of the Royal Society of Sciences in Uppsala