Darwin's Pangenesis Research Articles

150 years of Darwin's theory of intercellular flow of hereditary information.

Charles Darwin's Pangenesis theory, which proposed an intercellular mechanism for the flow of hereditary information, is gaining new ground.

Darwin's Pangenesis and Medical Genetics.

Darwin had many close connections with medical men, and made a number of observations on inherited diseases, clearly describing the inheritance of sex-linked diseases, inherited diseases at corresponding ages, infectious disease and the causes of diseases. Darwin's Pangenesis provides an alternative explanation for cancer metastasis, and is now supported by the discovery of circulating tumour DNA. The "genometastasis hypothesis" proposed by Garcia-Olmo etal. is consistent with Pangenesis. Darwin's view of animal regeneration and his pangenetic explanation is also supported by the recent finding regarding the role of small RNAs and extracellular vesicles in regeneration. There is increasing evidence for genetic information exchange between the donor and recipient cells during transplantation, supporting Darwin's "graft hybridization" concept that gemmules released from the cells of the stock (or scion) could move into the scion (or stock) and incorporated into their cells. In addition, there is also increasing evidence for transposition of the viscera. It appears to me that there is a need to expand the concept of Darwinian medicine by incorporating Darwin's Pangenesis into it.

Darwin's Pangenesis and the Lamarckian Inheritance of Acquired Characters.

Since the earliest days of evolutionary thought, the problem of the inheritance of acquired characters has been a central debate. Darwin accepted the inheritance of acquired characters as an established fact and gave many instances. His Pangenesis was more than anything else an attempt to provide a theory for its explanation. Over the past several decades, there has been increasing evidence for the inheritance of acquired habit and immunity, and for heritable changes induced by food and fertilizer, stress, chemicals, temperature, light and other environmental factors. Many studies also suggest that parental age has certain influences on the characters of offspring. The current explanations include environmentally induced DNA changes (mainly DNA rearrangements and DNA methylation), RNA-mediated inheritance, and horizontal gene transfer. These mechanistic explanations are consistent with Darwin's Pangenesis.

The Criticisms of Pangenesis: The Years of Controversy.

When first published in 1868, Darwin's Pangenesis was almost uniformly rejected by his contemporaries. Until recently it has still been regarded as Darwin's biggest mistake or a brilliant blunder. There are three main reasons for this. First, Galton transfused the blood of one variety of rabbit into another, and then bred together the latter. The results of breeding showed no variations of characters in the offspring. Thus he concluded thatDarwin's Pangenesis was incorrect. Second, there was no direct evidence for theexistence of Darwin's imaginary gemmules. Third, Darwin's Pangenesis explained the Lamarckian inheritance of acquired characters, graft hybridization, xenia and telegony, which were largely thought to be doubtful phenomena. Now the discoveries of circulating cell-free DNA, mobile RNAs, prions and extracellular vesicles provide striking evidence for the chemical existence of Darwin's supposed gemmules. There is also convincing evidence for heritable changes induced by blood transfusion in which Galton failed to find such effects in his experiment. Moreover, there is increasing evidence for the inheritance of acquired characters, graft hybridization, xenia and otherphenomena that Pangenesis was designed to explain. In light of the mounting evidence, it is not proper to continue to consider Pangenesis as Darwin's biggest mistake or a brilliant blunder.

In Search of Darwin's Imaginary Gemmules.

Darwin's gemmules were supposed to be "thrown off" by cells and were "inconceivably minute and numerous as the stars in heaven." They were capable of self-propagation and diffusion from cell to cell, and circulation through the system. The word "gene" coined by Wilhelm Johannsen, was derived from de Vries's term "pangen," itself a substitute for "gemmule" in Darwin's Pangenesis. Johannsen resisted the "morphological" conception of genes as particles with a certain structure. Morgan's genes were considered to be stable entities arranged in an orderly linear pattern on chromosomes, like beads on a string. In the late 1940s, McClintock challenged the concept of the stability of the gene when she discovered that some genes could move within a chromosome and between chromosomes. In 1948, Mandel and Metais reported the presence of cell-free nucleic acids in human blood for the first time. Over the past several decades, it has been universally accepted that almost all types of cells not only shed molecules such as cell-free DNA (including genomic DNA, tumor DNA and fetal DNA), RNAs (including mRNA and small RNAs) and prions, but also release into the extracellular environment diverse types of membrane vesicles (known as extracellular vesicles) containing DNA, RNA and proteins. Thus Darwin's speculative gemmules of the 19th century have become the experimentally demonstrated circulating cell-free DNA, mobile RNAs, prions and extracellular vesicles.

Darwin's Pangenesis and Certain Anomalous Phenomena.

Darwin clearly described certain anomalous phenomena, including what he referred to as "the direct action of the male element on the female form" and what we now call xenia and telegony, bud variation (mutation), reversion or atavism, and the inheritance and non-inheritance of mutilation. Some phenomena, particularly xenia, telegony and the inheritance of mutilation, were considered as doubtful phenomena by such authorities as Weismann and Morgan. Over the past 150 year, however, there has been increasing evidence for xenia, which is of great interest and importance in physiological research and plant production. The discoveries of cell-free fetal DNA, sperm RNAs, penetration of sperm into the somatic tissues of the female reproductive tract and the incorporation of exogenous DNA into somatic cells indicate that molecular mechanisms exist for telegony, one of the most controversial issues. Darwin's Pangenesis is the only theory that explains all the different types of phenomena.

Darwin's Pangenesis and Graft Hybridization.

Although there were many records of graft-induced variations in ancient China, it wasDarwin who coined the term "graft hybridization", the formation of hybrids between distinct species or varieties, through plant grafting, without the intervention of the sexual organs. He described many cases of the so-called "graft hybrids", in which shoots produced from grafted plants exhibited a combination of characters of both rootstock and scion, and explained their formation by his Pangenesis. Michurin invented "mentor-grafting" and "preliminary vegetative approximation" methods, which greatly increased the production of graft hybrids, thus providing a solution to Darwin's puzzle. Over the past decides, the existence of graft hybrids has been extensively documented, and graft hybridization is considered to be a simple and efficient means of plant breeding, and would be especially significant in the improvement of fruit trees. Graft hybridization is now explained by horizontal gene transfer and DNA transformation. In addition, the long-distance transport of mRNA and small RNAs is also considered to be involved in the formation of graft hybrids.

You are what your parents ate: A Darwinian perspective on the inheritance of food effects

Darwin's theory of evolution by natural selection is based on a sound understanding of the causes of variability and the mechanism of inheritance. Of all the causes which induce variability, Darwin believed that food was probably the most powerful. He not only held that the amount and nature of food could affect the characters of the future offspring through the reproductive system, but also accounted for the inheritance of such environmentally induced variations by his Pangenesis hypothesis. He proposed that cells could “throw off” numerous, minute molecules called gemmules, which were capable of diffusion from cell to cell, circulation throughout the body, modification by changed conditions of life (food, climate, etc.), aggregation in the reproductive organs, and transmission from parent to offspring. Now there is accumulating evidence that parental diets influence the health and disease of subsequent generations through epigenetic changes in germ cells. Two major underlying mechanisms are DNA methylation and RNA-mediated inheritance. A comparison of Darwin's imaginary gemmules with circulating cell-free DNA and mobile RNAs reveals intriguing similarities. It will be a fascinating episode in the history of science if Darwin's Pangenesis should eventually be rediscovered.

William Keith Brooks and the naturalist's defense of Darwinism in the late-nineteenth century.

William Keith Brooks was an American zoologist at Johns Hopkins University from 1876 until his death in 1908. Over the course of his career, Brooks staunchly defended Darwinism, arguing for the centrality of natural selection in evolutionary theory at a time when alternative theories, such as neo-Lamarckism, grew prominent in American biology. In his book The Law of Heredity (1883), Brooks addressed problems raised by Darwin's theory of pangenesis. In modifying and developing Darwin's pangenesis, Brooks proposed a new theory of heredity that sought to avoid the pitfalls of Darwin's hypothesis. In so doing he strengthened Darwin's theory of natural selection by undermining arguments for the inheritance of acquired characteristics. In later attacks on neo-Lamarckism, Brooks consistently defended Darwin's theory of natural selection on logical grounds, continued to challenge the idea of the inheritance of acquired characteristics, and argued that natural selection best explained a wide range of adaptations. Finally, he critiqued Galton's statistical view of heredity and argued that Galton had resurrected an outmoded typological concept of species, one which Darwin and other naturalists had shown to be incorrect. Brooks's ideas resemble the "biological species concept" of the twentieth century, as developed by evolutionary biologist Ernst Mayr and others. The late-nineteenth century was not a period of total "eclipse" of Darwinism, as biologists and historians have hitherto seen it. Although the "Modern Synthesis" refers to the reconciliation of post-Mendelian genetics with evolution by natural selection, we might adjust our understanding of how the synthesis developed by seeing it as the culmination of a longer discussion that extends back to the late-nineteenth century.

The concept of the causal role of chromosomes and genes in heredity and development: opponents from Darwin to Lysenko.

The idea of chromosomes and genes as causal agents in development and heredity originated in late 19th-century cytology, and it was most strongly supported by Theodor Boveri and Edmund B. Wilson. The concept of genes, which was central and most fruitful in classical genetics, appeared, however, unappealing and insufficient to many for explaining complex biological phenomena such as development.Philosophical outlooks, among them "Lamarckian" and holistic predilections, played a significant role in scientists' objection to genes as causal factors. A wide conceptual gap between genetics and developmental biology ensued. The strongest attack on the concept of genes was launched by agronomist and politician Trofim Lysenko in the Soviet Union under Stalin. Brushing aside the "Mendelist-Morganist" methods of classical genetics, Lysenko put forward a holistic concept of heredity that incorporated development and heritable responses to environmental conditions, similar to Darwin's Pangenesis theory, though of course some 60 years later. Recent developments include the role of genes in research on epigenetic marks and in systems approaches based on embryological gene regulatory networks.

Has Darwin's Pangenesis Been Rediscovered?

Has Darwin's Pangenesis Been Rediscovered?

Revisiting Darwin’s theory of heredity—Pangenesis

Pangenesis, an early theory of heredity, has been regarded as Darwin's error for a long time. The main reason is that it explains the inheritance of acquired characteristics and graft hybridization, which were largely thought to be wrong. In addition, Galton's blood transfusion experiments obtained negative results, and no evidence was found to support Darwin's hypothetical gemmules-molecular carriers of hereditary characteristics, which are supposed to be thrown off by cells and are able to circulate throughout the body. Now, there are growing evidence for the inheritance of acquired characteristics and graft hybridization. The discovery of circulating nucleic acids indicates that there are indeed inherited molecules which can move between cells of the organism, providing evidence for the chemical existence of Darwin's gemmules. This paper briefly introduces Darwin's Pangenesis, the main reasons that it was ignored, the new evidence in support of it and our own rethinking about it. A new understanding of Pangenesis brings a broader perspective on genetics, evolution, and medicine.

Does Darwin's Pangenesis have fatal flaws?

Does Darwin's Pangenesis have fatal flaws?

Darwin's Pangenesis and molecular medicine

Based on Hippocrates' pangenetic idea, Darwin elaborated his Pangenesis hypothesis to explain a host of phenomena including inherited diseases. The conventional wisdom is that Pangenesis is wrong because it explains the inheritance of acquired characteristics and no evidence was found to support his hypothetical gemmules - molecular carriers of hereditary characteristics. Now, growing evidence for the inheritance of acquired characteristics accumulates and the discovery of circulating nucleic acids provides evidence for the chemical existence of Darwin's gemmules, and a new understanding of Pangenesis brings a broader perspective on molecular medicine.

Darwin’s Gemmules and Development

Nowadays, Darwin's pangenesis hypothesis and his gemmule idea are considered to have been completely denied. However, the pangenesis hypothesis constituted, whereof we now often forget, an integral and essential part of Darwinism. There offered a hypothesis that probably to the certain period of embryonic development yet unidentified substances of specialized cells, tissues and organs of foetus, but not those of maternal organism, are cumulated in oocyte cytoplasms. These substances, so-called Darwin's gemmules (DGs), take part in determination and differentiation of a future embryo's cells. The approaches of experimental detection of DGs are also discussed.

A Novel Mechanism for Xenia?

Although xenia is widespread in plants and has applications in genetics, physiology, breeding and production, its mechanism remains poorly understood. Here I briefly discuss several previous explanations for xenia, and propose an mRNA action hypothesis, which is consistent with Darwin's Pangenesis.

Darwin's Pangenesis and the Problem of Unconceived Alternatives

In earlier work I have argued that the most substantial threat to scientific realism arises from the problem of unconceived alternatives: the repeated failure of past scientists and scientific communities to conceive of alternatives to extant scientific theories, even when such alternatives were both (1) well confirmed by the evidence available at the time and (2) sufficiently scientifically serious as to be later embraced by actual scientific communities. In this paper I explore Charles Darwin's development and defense of his ‘pangenesis’ theory of inheritance and conclude that this particular historical example offers impressive support for the challenge posed to realism by this problem of unconceived alternatives. 1. Introduction2. Darwin and pangenesis: The search for the material basis of generation and heredity3. A crucial unconceived alternative: common-cause mechanisms of inheritance4. Galton and common-cause inheritance5. Conclusion

Further evidence for Darwin's pangenesis.

Darwin's pangenesis, a developmental theory of heredity, has been largely thought to be wrong for more than a century. In this paper, further evidence for the inheritance of acquired characters and graft hybridization is provided. A striking similarity between mRNA and Darwin's so-called gemmule has been found by comparing their nature and function. I propose that once the term gemmule has been replaced by mRNA, Darwin's pangenesis will revive, indicating an important step in biology.

An Alleged Case of Inheritance of Acquired Characters

Previous articleNext article No AccessAn Alleged Case of Inheritance of Acquired CharactersC. B. DavenportC. B. Davenport Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 67, Number 713Nov. - Dec., 1933 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/280514 Views: 2Total views on this site Citations: 6Citations are reported from Crossref PDF download Crossref reports the following articles citing this article:Yongsheng Liu Darwin's Pangenesis and Graft Hybridization, (Jan 2018): 27–66.https://doi.org/10.1016/bs.adgen.2018.05.007Yongsheng Liu The Criticisms of Pangenesis, (Jan 2018): 31–61.https://doi.org/10.1016/bs.adgen.2018.05.002Yongsheng Liu Darwin's Pangenesis and Certain Anomalous Phenomena, (Jan 2018): 93–120.https://doi.org/10.1016/bs.adgen.2018.05.009Y.-S. Liu Inheritance of acquired characters in animals: A historical overview, further evidence and mechanistic explanations, Italian Journal of Zoology 78, no.44 (Dec 2011): 410–417.https://doi.org/10.1080/11250003.2011.562554Y. -S. Liu, X. M. Zhou, M. X. Zhi, X. J. Li, Q. L. Wang Darwin’s contributions to genetics, Journal of Applied Genetics 50, no.33 (Sep 2009): 177–184.https://doi.org/10.1007/BF03195671Morris Steggerda Charles Benedict Davenport (1866-1944); The man and his contributions to physical anthropology, American Journal of Physical Anthropology 2, no.22 (Jun 1944): 167–185.https://doi.org/10.1002/ajpa.1330020205

Charles Darwin and the Mutation Theory

Next article FreeCharles Darwin and the Mutation TheoryCharles F. CoxCharles F. Cox Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 43, Number 506Feb., 1909 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/279022 Views: 158Total views on this site Citations: 5Citations are reported from Crossref PDF download Crossref reports the following articles citing this article:Hein van Grouw, Wim Dekkers The taxonomic history of Black-shouldered Peafowl; with Darwin's help downgraded from species to variation, Bulletin of the British Ornithologists’ Club 143, no.11 (Mar 2023).https://doi.org/10.25226/bboc.v143i1.2023.a7Yongsheng Liu Darwin's Pangenesis and Graft Hybridization, (Jan 2018): 27–66.https://doi.org/10.1016/bs.adgen.2018.05.007Yongsheng Liu The Influence of Darwin's Pangenesis on Later Theories, (Jan 2018): 63–85.https://doi.org/10.1016/bs.adgen.2018.05.003Joel S. Brown Why Darwin would have loved evolutionary game theory, Proceedings of the Royal Society B: Biological Sciences 283, no.18381838 (Sep 2016): 20160847.https://doi.org/10.1098/rspb.2016.0847Y. -S. Liu, X. M. Zhou, M. X. Zhi, X. J. Li, Q. L. Wang Darwin’s contributions to genetics, Journal of Applied Genetics 50, no.33 (Sep 2009): 177–184.https://doi.org/10.1007/BF03195671