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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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.
In chapters 17 and 18 of GA 1, Aristotle outlines in detail the various arguments in favor of pangenesis, and he rejects each in turn.
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.
Working in his study at Down House (see Figure 1), Darwin added several unique touches to the explanations for the source of variation and mechanism of inheritance available at the time and proposed what he called the provisional hypothesis of pangenesis (1868b, 1875).
Other feminists criticize Aristotle's theory as inferior to the other of his rival theories, pangenesis.(26) Pangenesis, in Empedocles' version, holds that male and female both make contributions of the same sort,(27) and so this theory appears more acceptable by general feminist criteria.
On the other hand, if there is something in the fetation from the start that forms it, Aristotle is then dangerously close to the pangenesis and preformation theories which hold that the miniaturized creature or the parts of the creature are already in the generative fluid.
This mechanism was called pangenesis (Moore, 1993), a term that means "originating from everywhere." Interestingly, Hippocrates further implied that changes to the adult could, through this mechanism, be shared with future offspring--which makes him a Lamarckian too.
Given that the ancient scholars were read during Victorian times, it is likely that Darwin may have become vaguely acquainted with the principle of pangenesis years earlier, even without retaining a clear memory of the link.