From Hopeful Monsters to Homeotic Effects: Richard Goldschmidt's Integration of Development, Evolution, and Genetics

Richard Goldschmidt's research on homeotic mutants from 1940until his death in 1958 represents one of the first seriousefforts to integrate genetics, development, and evolution. Usingtwo different models, Goldschmidt tried to show how differentviews of genetic structure and gene action could provide a mechanismfor rapid speciation. Developmental systems were emphasizedin one model and a hierarchy of genetic structures in the other.While Goldschmidt tried to find a balance between developmentand genetics, critics, such as Sewall Wright, urged him andeventually helped him incorporate population dynamics into hismodels as well. As such, the history of Goldschmidt's researchon homeotic mutants highlights the continuing challenge of producinga balanced and integrated developmental evolutionary genetics.     

Macromutation and evolution: the fixation of Goldschmidt's macromutations as species and genus traits. Hairlessness mutations in mammals

A brief survey of the development of concepts on the role of macromutations in evolution is given. Contrary to Iu. A. Filipchenko (1926, 1927), who introduced the "micro- and macromutation" terms and believed that regularities of macroevolution could not be reduced to microevolutionary processes, the majority of "synthetists" explained any form of evolution by changes in allele frequencies. From the studies of Drosophila homoeotic mutants R. Goldschmidt (1940) developed the concept of "hopeful monsters" and their role in macroevolution. However, the homoeotic mutants are of drastically reduced viability, which allows the gradualists to reject Goldschmidt's ideas. The distribution of hairlessness mutations (hairless, nude etc.) with the monogenic pattern of inheritance in mammals was studied. Hairless mutants are known in Peromyscus, Mus musculus, Rattus rattus, R. norvegicus, Canis familiaris, Ovis aries. Hairlessness as norm is found in 53 among contemporaneous 1037 mammalian genera. Part of these cases (hairlessness in all Cetacea and Sirenia) may be explained in terms of both macromutations and obligatory gradualism. There is no doubt as to the macromutational origin of hairlessness in the bat Cheiromeles and the rodent Heterocephalus (Bathyergidae); the genera systematically and ecologically close to these have normal pelage. It is quite possible that hairlessness of walrus (Odobenus) has the same origin. The appearance and fixation of single Goldschmidt's macromutation cannot yet be considered as a macroevolutionary process, though the possibility of fixation of a macromutation in nature as a species and genus character contradicts strongly the concept of obligatory gradualism of evolution.     

Richard Goldschmidt: hopeful monsters and other 'heresies'

Richard Goldschmidt is remembered today as one of the most controversial biologists of the twentieth century. Although his work on sex determination and physiological genetics earned him accolades from his peers, his rejection of the classical gene and his unpopular theories about evolution significantly damaged his scientific reputation. This article reviews Goldschmidt's life and work, with an emphasis on his controversial views.     

Early 20th-century research at the interfaces of genetics, development, and evolution: reflections on progress and dead ends

Three early 20th-century attempts at unifying separate areas of biology, in particular development, genetics, physiology, and evolution, are compared in regard to their success and fruitfulness for further research: Jacques Loeb's reductionist project of unifying approaches by physico-chemical explanations; Richard Goldschmidt's anti-reductionist attempts to unify by integration; and Sewall Wright's combination of reductionist research and vision of hierarchical genetic systems. Loeb's program, demanding that all aspects of biology, including evolution, be studied by the methods of the experimental sciences, proved highly successful and indispensible for higher level investigations, even though evolutionary change and properties of biological systems up to now cannot be fully explained on the molecular level alone. Goldschmidt has been appraised as pioneer of physiological and developmental genetics and of a new evolutionary synthesis which transcended neo-Darwinism. However, this study concludes that his anti-reductionist attempts to integrate genetics, development and evolution have to be regarded as failures or dead ends. His grand speculations were based on the one hand on concepts and experimental systems that were too vague in order to stimulate further research, and on the other on experiments which in their core parts turned out not to be reproducible. In contrast, Sewall Wright, apart from being one of the architects of the neo-Darwinian synthesis of the 1930s, opened up new paths of testable quantitative developmental genetic investigations. He placed his research within a framework of logical reasoning, which resulted in the farsighted speculation that examinations of biological systems should be related to the regulation of hierarchical genetic subsystems, possibly providing a mechanism for development and evolution. I argue that his suggestion of basing the study of systems on clearly defined properties of the components has proved superior to Goldschmidt's approach of studying systems as a whole, and that attempts to integrate different fields at a too early stage may prove futile or worse.     

Epigenetics and the renaissance of heresy.

Classic neo-Darwinian theory is predicated on the notion that all heritable phenotypic change is mediated by alterations of the DNA sequence in genomes. However, evidence is accumulating that stably heritable phenotypes can also have an epigenetic basis, lending support to the long-discarded notion of inheritance of acquired traits. As many of the examples of epigenetic inheritance are mediated by position effects, the possibility exists that chromosome rearrangements may be one of the driving forces behind evolutionary change by exerting position effect alterations in gene activity, an idea articulated by Richard Goldschmidt. The emerging evidence suggests that Goldschmidt's controversial hypothesis deserves a serious reevaluation.     

Darwinism and the Origin of Life: The Role of H.C. Bastian in the British Spontaneous Generation Debates, 1868--1873

Henry Charlton Bastian's support for spontaneous generation is shown to have developed from his commitment to the new evolutionary science of Darwin, Spencer, Huxley and Tyndall. Tracing Bastian's early career development shows that he was one of the most talented rising young stars among the Darwinians in the 1860s. His argument for a logically necessary link between evolution and spontaneous generation was widely believed among those sympathetic to Darwin's ideas. Spontaneous generation implied materialism to many, however, and it had associations in Britain with radical politics and amateur science. Huxley and the X Club were trying to create a public posture of Darwinism that kept it at arm's length from those negative associations. Thus, the conflict that developed when Huxley and the X Club opposed Bastian was at least as much about factional in-fighting among the Darwinians as it was about the experiments under dispute. Huxley's strategy to defeat Bastian and define his position as “non-Darwinian” contributed significantly to the shaping of Huxley's famous address “Biogenesis and Abiogenesis.” Rhetorically separating Darwinism from Bastian was thus responsible for Huxley's first clear public statement that a naturalistic origin of life was compatible with Darwin's ideas, but only in the earth's distant past. The final separation of the discourse on the meaning of Brownian movement and “active molecules” from any possible link with spontaneous generation also grew out of Huxley's strategy to defeat Bastian. Clashes between Bastian and the X Club are described at the BAAS, the Royal Society, and in the pages of Nature and other journals. This revised version was published online in July 2006 with corrections to the Cover Date.     

Of moths and men: Theo Lang and the persistence of Richard Goldschmidt's theory of homosexuality, 1916-1960

Using an analogy between moths and men, in 1916, Richard Goldschmidt proposed that homosexuality was a case of genetic intersexuality. As he strove to create a unified theory of sex determination that would encompass animals ranging from moths to men, Goldschmidt's doubts grew concerning the association of homosexuality with intersexuality until, in 1931, he dropped homosexuality from his theory of intersexuality. Despite Goldschmidt's explicit rejection of his theory of homosexuality, Theo Lang, a researcher in the Genealogical-Demographic Department of the Institute for Psychiatric Research in Munich, revived it, maintained Goldschmidt's association with it, and argued on its behalf in publications from 1936 to 1960. Lang's appropriation of Goldschmidt's theory did not depend on his resolution of the difficulties Goldschmidt had found with his own theory. Lang and Goldschmidt, I argue, had fundamentally different scientific and social commitments that allowed one to reject this theory of homosexuality and the other to accept it.     

The main postulate of the vertical evolution theory

In the series of previous publications by the author (2000, 2002, 2005), a genetic model explaining the phenomenon of evolutionary progress was presented. In the present paper, this model is described in general terms. The model is based on views on regular changes of ecological potential of organisms on a macroevolutionary time scale. According to these views, macroevolution has its own pattern, which cannot be seen in the microevolutionary process. Hence, the statement of the synthetic theory of evolution that "macroevolution proceeds via microevolution" is incorrect.     

Examining the Interaction of Acceptance and Understanding: How Does the Relationship Change with a Focus on Macroevolution?

The goal of this research was to illuminate the relationship between students’ acceptance and understanding of macroevolution. Our research questions were: (1) Is there a relationship between knowledge of macroevolution and acceptance of the theory of evolution?; (2) Is there a relationship between the amount of college level biology course work and acceptance of evolutionary theory and knowledge of macroevolution?; and (3) Can college student acceptance of the theory of evolution and knowledge of macroevolution change over the course of a semester? The research participants included 667 students from a first-semester biology course and 74 students from the evolutionary biology course. Data were collected using both the MATE (a measure of the acceptance of evolutionary theory) and the MUM (a measure of understanding of macroevolution). Pre-instruction data were obtained for the introductory biology course, and pre- and post-data were obtained for the evolutionary biology course. Analysis revealed acceptance of evolution (as measured by the MATE) was correlated to understanding of macroevolution, and the number of biology courses was significantly correlated to acceptance and knowledge of macroevolution. Finally, there was a statistically significant change in students’ understanding of macroevolution and acceptance of evolution after the one-semester evolutionary biology course. Significance of these findings is discussed.     

再谈“有希望的怪物”

1933年,遗传学家Goldschmidt提出＂有希望的怪物＂假说,以解释宏演化（macroevolution）中有别于＂达尔文式＂的演化机制。近年来,有关内共生和基因倍增等进展表明,＂有希望的怪物＂在自然界中其实非常普遍。这虽然与＂现代综合进化论＂的观点不甚一致,但却能在经典达尔文主义找到契合点：作为自然选择的补充,＂有希望的怪物＂可以为宏演化提供一种潜在的候选机制。这种建立在多元论基础上的进化观是达尔文留给后人最宝贵的遗产。     

On Darwin's 'metaphysical notebooks'. I: teleology and the project of a theory.

Huxley's essay On the Reception of the 'Origin of Species' brings us close to the issue of cause and of why- and how-questions in the understanding of the living world. The present contribution, which is divided into two parts, reviews the problem of Teleology as conceived by Huxley and re-examines Darwin as the author who revealed the existence of a 'foundations problem' in the explanation of an entire realm of nature, i.e., the problem of explaining such realm in terms of its own, specific legality, or iuxta sua propria principia. In the first part the enquiry is mainly focused on the secularization of natural history after Paley; in the second part it is mainly focused on the desubjectivization of the inquiry into natural history after Erasmus Darwin and Lamarck. The second part will be published in the next issue of Rivista di Biologia/Biology Forum. In the first part below an analysis is made of Notebooks M and N. The author disputes the correctness of conceiving them only as the works where Darwin envisages the 'metaphysical' themes later to become the subject of The Expression of the Emotions. He suggests to conceive of them also as the works where Darwin defines the terms of the general project of his own, peculiar evolutionary theory. The author then outlines the intellectual progress of Darwin from the inosculation to the transmutation hypotheses. Darwin's reading of Malthus appears to be analytically decisive, because it offers him the vintage point to attack the metaphysical and theological citadels on the morphological side. Darwin is thus able to re-consider Erasmus' comprehensive zoonomic project, by displacing it, however, from the old idea of the scala naturae to the new one of the "coral of life", and by emphasising the distinction between "the fittest" and "the best" vs. the tradition of Natural Theology.     

Thomas Henry Huxley (1825-1895) puts us in our place

Thomas Huxley was one of the 19th century's most active defenders of Darwin's idea that life has evolved through natural processes. An anatomist and paleontologist, he extended his energies to science and education policy, the democratization of science, and the broad societal implications of evolution. Since his time the fossil record has greatly improved and the genetic 'revolution' has occurred, deepening our understanding of primate and human evolution in ways that would please Huxley: improved systematics relies heavily on genetic data, and molecular technologies are opening our understanding of the genetic basis of complex traits of traditional anthropological interest-but in ways that are thoroughly dependent on the fact of evolution. A more unified biological synthesis is forming that unites genes, developmental process, structure, and inheritance. But the tempo and mode of evolution remain unresolved. Huxley was one of many who have had trouble accepting Darwin's gradual natural selection as the central evolutionary mechanism, and views spanning the antipodes of gradualism and saltation find advocates even in our genetic era.     

Unifying macroecology and macroevolution to answer fundamental questions about biodiversity

The study of biodiversity started as a single unified field that spanned both ecology and evolution and both macro and micro phenomena. But over the 20th century, major trends drove ecology and evolution apart and pushed an emphasis towards the micro perspective in both disciplines. Macroecology and macroevolution re‐emerged as self‐consciously distinct fields in the 1970s and 1980s, but they remain largely separated from each other. Here, we argue that despite the challenges, it is worth working to combine macroecology and macroevolution. We present 25 fundamental questions about biodiversity that are answerable only with a mixture of the views and tools of both macroecology and macroevolution.     

The main postulate of the theory of vertical evolution

In the series of previous publications by the author (2000, 2002, 2005), a genetic model explaining the phenomenon of evolutionary progress was presented. In the present paper, this model is described in general terms. The model is based on views on regular changes of ecological potential of organisms on a macroevolutionary time scale. According to these views, macroevolution has its own pattern, which cannot be seen in the microevolutionary process. Hence, the statement of the synthetic theory of evolution that “macroevolution proceeds via microevolution” is incorrect.     

Ancon sheep: a now disproven example of macroevolution.

The Ancon breed of sheep provided, for decades, a critical support for the existence of major evolutionary changes or jumps called "sports." Putative examples of sports have been used as evidence of rapid macroevolution since Darwin first discussed the Ancon sheep mutation in 1859. Ancon sheep had very short legs that were considered an advantage for shepherds because the sheep were less likely to escape over fences. Many textbooks and articles implied that the breed was an example of how a major new trait could evolve in a single generation. The Ancon sheep example has been used both to prove gradual Darwinism and also to argue for rapid evolution as opposed to gradualism. It now is recognized that Ancon sheep resulted from genetic diseases, and that they usually suffered from achondroplasia. The so-called new breed had so many major health problems that the condition caused the breed's extinction decades ago, yet was mentioned in textbooks as evidence for evolutionary jumps as recently as 2005.     

Macroevolution is more than repeated rounds of microevolution

SUMMARY Arguments over macroevolution versus microevolution have waxed and waned through most of the twentieth century. Initially, paleontologists and other evolutionary biologists advanced a variety of non-Darwinian evolutionary processes as explanations for patterns found in the fossil record, emphasizing macroevolution as a source of morphologic novelty. Later, paleontologists, from Simpson to Gould, Stanley, and others, accepted the primacy of natural selection but argued that rapid speciation produced a discontinuity between micro- and macroevolution. This second phase emphasizes the sorting of innovations between species. Other discontinuities appear in the persistence of trends (differential success of species within clades), including species sorting, in the differential success between clades and in the origination and establishment of evolutionary novelties. These discontinuities impose a hierarchical structure to evolution and discredit any smooth extrapolation from allelic substitution to large-scale evolutionary patterns. Recent developments in comparative developmental biology suggest a need to reconsider the possibility that some macroevolutionary discontinuites may be associated with the origination of evolutionary innovation. The attractiveness of macroevolution reflects the exhaustive documentation of large-scale patterns which reveal a richness to evolution unexplained by microevolution. If the goal of evolutionary biology is to understand the history of life, rather than simply document experimental analysis of evolution, studies from paleontology, phylogenetics, developmental biology, and other fields demand the deeper view provided by macroevolution.     

A review of the diversity and evolution of photonic structures in butterflies, incorporating the work of John Huxley (The Natural History Museum, London from 1961 to 1990)

The photonic structures of butterfly wings are among the most anatomically diverse of all those in nature, giving rise to an unrivalled display of structural colours. These have recently become the focus of research by workers in a variety of disciplines, stimulated by their potential applications to technology ('biomimetics'). This interest, together with the discovery of unpublished electron micrographs taken by the late Dr John Huxley (Natural History Museum, London), prompted this review of butterfly photonics in general. The current work provides a synopsis of the literature to date, covering the diversity and evolution of these optical structures and incorporating Huxley's work, which represents an important biomimetic and evolutionary database on its own. This review deals with butterfly photonic devices according to the parts of the butterfly scales on which they occur. In this way, the information is ripe for evolutionary study.     

Georges Teissier (1900–1972) and the Modern Synthesis in France

This Perspectives is devoted to the ideas of the French zoologist Georges Teissier about the mechanisms of evolution and the relations between micro- and macroevolution. Working in an almost universally neo-Lamarckian context in France, Teissier was one of the very few Darwinians there at the time of the evolutionary synthesis. The general atmosphere of French zoology during the 1920s and the 1930s will first be recalled, to understand the specific conditions in which Teissier became a zoologist. After a brief overview of his joint work with Philippe L’Héritier on the experimental genetics of Drosophila, this article describes the ways Teissier, during the 1950s, conceptualized the mechanisms that could allow for macroevolutionary transitions.IT is usually acknowledged that France did not significantly participate in the elaboration of 20th century evolutionary theory, often designated The Modern Synthesis. In their classical book on the history of the synthesis, Ernst Mayr and William B. Provine devoted a whole—nonetheless small—chapter to this specific issue (Mayr and Provine 1998, pp. 309–328). Mayr clearly stated that “France is the only major scientific nation that did not contribute significantly to the evolutionary synthesis” (Mayr 1998, p. 309). In the absence of a French architect of the synthesis, Mayr and Provine asked Ernest Boesiger, a Swiss population geneticist and a former student of Georges Teissier, to tell the story of what had happened in French biology at the time of the evolutionary synthesis. Boesiger, who died in 1975, wrote a paper in 1974 that provided the firm basis of the chapter. In very strong terms, he depicted French biology as “a kind of living fossil in the rejection of modern evolutionary theories” (Boesiger 1998, p. 309). He insisted on the fact that, even in 1974, most French biologists and philosophers were still reluctant to accept Darwinism. As regards the period of the 1930s, Boesiger was able to think of only two exceptions: Georges Teissier and Philippe L’Héritier. He then referred to their joint research in population genetics, which was based on the new technique of the population cages with the species Drosophila melanogaster, and listed their contributions to this new discipline.If Teissier and L’Héritier’s works on Drosophila are nowadays more widely recognized than in 1974, due in particular to the efforts of Jean Gayon and Michel Veuille (Gayon and Veuille 2001), this recognition could have as an unintended consequence the reduction of both Teissier and L’Héritier to being simply the inventors of a useful technique, namely the population cages (see especially how Mayr presented their work in his other classical book, Mayr 1982, p. 574), or as the founders of a French school of population geneticists (Gayon and Veuille 2001). The aim of this article is to reevaluate the way Georges Teissier (1900–1972) conceived Darwinian natural selection not only as an important mechanism for evolution at the population level but more fundamentally as a general key for the unification of biology, exactly as Julian Huxley or Ernst Mayr did during the same period (1930–1970). However, starting in the early 1950s, Teissier went on to conceive a very specific understanding of the evolutionary synthesis.In this article, I will first describe the general atmosphere of evolutionary issues in French biology at the time when Teissier started working as a zoologist, to understand against what he developed his joint research program with L’Héritier and afterward his general conceptions about evolution. During the 1930s and the 1940s, only a very few scientists in France could be seen as Darwinians. In addition to Teissier and L’Héritier, one may also consider Marcel Prenant, Boris Ephrussi, and the mathematician Gustave Malécot. Building on Jean Gayon and Michel Veuille’s work, I will then give a quick overview of L’Héritier and Teissier’s most important achievements in the field of population genetics. In the third part, I will discuss the discovery made by Teissier and L’Héritier of a case of cytoplasmic inheritance in Drosophila. This unexpected finding led them into the field of non-Mendelian heredity. I will then develop in detail the way Teissier finally went on to conceive the relation between microevolution and macroevolution, in light of the general context of French biology and of the development of the field of cytoplasmic inheritance.