Pangenesis


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pangenesis

[pan′jen·ə·səs]
(biology)
Darwin's comprehensive theory of heredity and development, according to which all parts of the body give off gemmules which aggregate in the germ cells; during development, they are sorted out from one another and give rise to parts similar to those of their origin.

Pangenesis

 

a speculative theory of heredity and development.

According to Hippocrates, who lived in the fifth and fourth centuries B.C., close physical resemblances between children and their parents were caused by the fact that in animals and man “the seed separates from the rest of the body.” Similar views were developed in the 17th century by G. Borelli and in the 18th century by G. Buffon. In 1868, C. Darwin advanced the concept of pangenesis in his “provisional hypothesis of pangenesis.” Attempting to encompass in a single theory the phenomena of individual development and of variability, heredity, and phylo-genetic development, Darwin suggested that submicroscopic germs called gemmules migrate from all parts of the body through the circulatory system to the sex cells. The gemmules ensure that descendants will develop characteristics similar to those of their parents, including newly acquired characteristics. Darwin’s hypothesis received neither support nor empirical confirmation. Thus, F. Galton, attempting in 1871 to ascertain whether there are gemmules in the blood that determine the color of hair, transfused blood from dark-colored rabbits to light-colored ones and found that the transfusion caused no change in the coloring of the offspring. Darwin’s hypothesis of pangenesis is important in that it contains the concept, later confirmed, of the discreteness, or corpuscular nature, of the material basis of heredity.

Intracellular pangenesis, a hypothesis advanced by H. de Vries in 1889, suggested that hereditary instincts are caused by the presence of material particles (pangens) in living protoplasm. In contrast to Darwin, de Vries denied that pangens were transferred to the sex cells; he believed that each cell nucleus from its very inception contains all the pangens distinctive to a given individual. Elements of de Vries’ hypothesis have been proven valid in modern biology, especially since the successful transplantation of somatic cell nuclei to egg cells without nuclei has proved that complete genetic information is contained in the nuclei of the body’s cells.

REFERENCES

Darwin, C. Soch., vol. 4. Moscow-Leningrad, 1951.
Vries, H. de. Intracellulare Pangenesis. Jena, 1889.

L. IA. BLIAKHER

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Pangenesis posits that each and every part of an organism produces "gemmules" during every stage of the organism's development from embryo to adult.
He became extremely angry, however, when his cousin Francis Galton empirically disproved pangenesis by transfusing blood from one type of rabbit into another to see whether the differences could be passed on to the offspring.
The word gene was derived from Hugo De Vries's term pangen, itself a derivative of the word pangenesis which Darwin (1809-1882) had coined in 1868.
His theory of pangenesis, for example, states that each part of the adult body produces gemmules that make their way into the sexual organs for reproduction; in this way, traits acquired by adults can be passed on to their young.
This is not a direct inheritance of acquired characteristics through a means such as Darwin's pangenesis, but an indirect transmission through operant behavior, social learning, genetic assimilation, and natural selection.
He was wrong, however, about genetics, concocting his neo-Lamarkian theory of pangenesis at the same time as Mendel was conducting his experiments.
Pero la teoria de la pangenesis de Darwin sigue esa misma concepcion.
La pangenesis de Darwin conduce directamente a la herencia de los caracteres adquiridos, le proporciona un fundamento fisiologico, pues las gemulas recogen los cambios que sufren las partes del organismo de las que proceden.
The pendulum subsequently oscillated once more toward pangenesis, gaining tentative adherence among others from Charles Darwin, according to whose "Provisional Hypothesis of Pangenesis" the complete body contributes to heredity: atoms from the entire body of both mother and father are united in their offspring.
Here, rather than dwell on the fact of a Darwinian error, I will focus on why the error was made, the reactions of Darwin and his colleagues to pangenesis, and what it can teach us about how science functions.
He presents a variety of reasons for objecting to pangenesis and preformation.
Darwin's proposal went by the curious name pangenesis.