Gemmules
Encyclopedia
Gemmules were imagined particles of inheritance proposed by
Charles Darwin
as part of his Pangenesis
theory. This appeared in his book The Variation of Animals and Plants under Domestication
, published in 1868, nine years after the publication of his famous book On the Origin of Species.
Gemmules, also called plastitudes or pangenes
, were assumed to be shed by the organs of the body and carried in the bloodstream to the reproductive organs where they accumulated in the germ cells or gametes. They thus provided a possible mechanism for the inheritance of acquired characteristics, as proposed by Jean-Baptiste Lamarck
, which Darwin believed to be a cause of the observed variation in living organisms.
This was prior to Gregor Mendel
's discovery of the particulate nature of inheritance
becoming common knowledge among biologist
s after their rediscovery in 1900.
(from Charles Darwin: The Power of Place by E. Janet Browne
):
Gemmules were imagined particles of inheritance proposed by Charles Darwin as part of his Pangenesis theory. This appeared in his book The Variation of Animals and Plants under Domestication, published in 1868, nine years after the publication of his famous book On the Origin of Species.
Gemmules, also called plastitudes or pangenes, were assumed to be shed by the organs of the body and carried in the bloodstream to the reproductive organs where they accumulated in the germ cells or gametes. They thus provided a possible mechanism for the inheritance of acquired characteristics, as proposed by Jean-Baptiste Lamarck, which Darwin believed to be a cause of the observed variation in living organisms.
This was prior to Gregor Mendel's discovery of the particulate nature of inheritance becoming common knowledge among biologists after their rediscovery in 1900.
Charles Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
as part of his Pangenesis
Pangenesis
Pangenesis was Charles Darwin's hypothetical mechanism for heredity. He presented this 'provisional hypothesis' in his 1868 work The Variation of Animals and Plants under Domestication and felt that it brought 'together a multitude of facts which are at present left disconnected by any efficient...
theory. This appeared in his book The Variation of Animals and Plants under Domestication
The Variation of Animals and Plants under Domestication
The Variation of Animals and Plants under Domestication is a book written by Charles Darwin that was first published in January 1868.A large proportion of the book contains detailed information on the domestication of animals and plants but it also contains in Chapter XXVII a description of...
, published in 1868, nine years after the publication of his famous book On the Origin of Species.
Gemmules, also called plastitudes or pangenes
Pangenesis
Pangenesis was Charles Darwin's hypothetical mechanism for heredity. He presented this 'provisional hypothesis' in his 1868 work The Variation of Animals and Plants under Domestication and felt that it brought 'together a multitude of facts which are at present left disconnected by any efficient...
, were assumed to be shed by the organs of the body and carried in the bloodstream to the reproductive organs where they accumulated in the germ cells or gametes. They thus provided a possible mechanism for the inheritance of acquired characteristics, as proposed by Jean-Baptiste Lamarck
Jean-Baptiste Lamarck
Jean-Baptiste Pierre Antoine de Monet, Chevalier de la Marck , often known simply as Lamarck, was a French naturalist...
, which Darwin believed to be a cause of the observed variation in living organisms.
This was prior to Gregor Mendel
Gregor Mendel
Gregor Johann Mendel was an Austrian scientist and Augustinian friar who gained posthumous fame as the founder of the new science of genetics. Mendel demonstrated that the inheritance of certain traits in pea plants follows particular patterns, now referred to as the laws of Mendelian inheritance...
's discovery of the particulate nature of inheritance
Mendelian inheritance
Mendelian inheritance is a scientific description of how hereditary characteristics are passed from parent organisms to their offspring; it underlies much of genetics...
becoming common knowledge among biologist
Biologist
A biologist is a scientist devoted to and producing results in biology through the study of life. Typically biologists study organisms and their relationship to their environment. Biologists involved in basic research attempt to discover underlying mechanisms that govern how organisms work...
s after their rediscovery in 1900.
Quotes
(from The Variation of Plants and Animals under Domestication (1868), Charles Darwin)It is universally admitted that the cells or units of the body increase by self-division, or proliferation, retaining the same nature, and that they ultimately become converted into the various tissues and substances of the body. But besides this means of increase I assume that the units throw off minute granules which are dispersed throughout the whole system; that these, when supplied with proper nutriment, multiply by self-division, and are ultimately developed into units like those from which they were originally derived. These granules may be called gemmules. They are collected from all parts of the system to constitute the sexual elements, and their development in the next generation forms the new being; but they are likewise capable of transmission in a dormant state to future generations and may then be developed.)
(from Charles Darwin: The Power of Place by E. Janet Browne
E. Janet Browne
Elizabeth Janet Browne is a British historian of science known especially for her work on the history of 19th century biology. She taught at the Wellcome Trust Centre for the History of Medicine, University College, London, before returning to Harvard...
):
Individual gemmules did not contain a complete microscopic blueprint for an entire creature in the way that Herbert Spencer or Carl von Nägeli described.' (p.276)
Pangenesis looked to him as if it might supply the answer. Darwin proposed that some limited effects from the environment might become embedded in an individual’s constitution and thus be liable to be transmitted, via the gemmules, to the offspring. (p.281)
But Darwin now wanted to include in his scheme the possibility of the inheritance of some limited acquired characteristics. Pangenesis gave him the chance to be Lamarckian without any of Lamarck’s inner strivings. As he put it, some aspects of the external environment could modify the inheritable gemmules.
In variations caused by the direct actions of changed conditions, of which several instances have been given, certain parts of the body are directly affected by the new conditions, and consequently throw off modified gemmules, which are transmitted to the offspring.18
No doubt the whole hypothesis of pangenesis was extremely complicated, he conceded. “But so are the facts.” (p.283–284)
Galton was troubled because he began the work in good faith, intending to prove Darwin right; and he praised pangenesis in Hereditary Genius in 1869. Somehow he had unintentionally proved Darwin wrong. Cautiously, he criticised his cousin’s theory, although qualifying his remarks by saying that Darwin’s gemmules (he called them “pangenes”) might be only temporary inhabitants of the blood and that his experiments could have failed to pick them up. (p.291–292)
Gemmules were imagined particles of inheritance proposed by Charles Darwin as part of his Pangenesis theory. This appeared in his book The Variation of Animals and Plants under Domestication, published in 1868, nine years after the publication of his famous book On the Origin of Species.
Gemmules, also called plastitudes or pangenes, were assumed to be shed by the organs of the body and carried in the bloodstream to the reproductive organs where they accumulated in the germ cells or gametes. They thus provided a possible mechanism for the inheritance of acquired characteristics, as proposed by Jean-Baptiste Lamarck, which Darwin believed to be a cause of the observed variation in living organisms.
This was prior to Gregor Mendel's discovery of the particulate nature of inheritance becoming common knowledge among biologists after their rediscovery in 1900.
External links
- The Variation of Animals and Plants under Domestication Full text online