Classical Genetics

There is at present uneasiness about the conceptual basis of genetics. The gene concept has become blurred and there are problems with the distinction between genotype and phenotype. In the present paper I go back to their role in the creation of modern genetics in the early twentieth century. The terms were introduced by the Danish botanist and geneticist Wilhelm Johannsen in his big textbook of 1909. Historical accounts usually concentrate on this book and his 1911 paper “The Genotype Conception (...) of Heredity.” His bean selection experiment of 1900–1903 is generally assumed to be the source of his genotype theory. The present paper examines the scientific context and meaning of this experiment, how it was received, and how the genotype theory became securely established by the early 1910s. I argue in conclusion that the genotype/phenotype distinction, which provides the empirical basis for Johannsen's gene, was scientifically well founded when introduced and still is. Keith Baverstock's criticism does not consider the force of the bean selection experiment at the time and as a paradigm for following investigations of heredity. (shrink)

There is at present uneasiness about the conceptual basis of genetics. The gene concept has become blurred and there are problems with the distinction between genotype and phenotype. In the present paper I go back to their role in the creation of modern genetics in the early twentieth century. The terms were introduced by the Danish botanist and geneticist Wilhelm Johannsen in his big textbook of 1909. Historical accounts usually concentrate on this book and his 1911 paper “The Genotype Conception (...) of Heredity.” His bean selection experiment of 1900–1903 is generally assumed to be the source of his genotype theory. The present paper examines the scientific context and meaning of this experiment, how it was received, and how the genotype theory became securely established by the early 1910s. I argue in conclusion that the genotype/phenotype distinction, which provides the empirical basis for Johannsen's gene, was scientifically well founded when introduced and still is. Keith Baverstock's criticism does not consider the force of the bean selection experiment at the time and as a paradigm for following investigations of heredity. (shrink)

One claim found in the received historiography of the biometrical school (comprised primarily of Francis Galton, Karl Pearson, and W. F. R. Weldon) is that one of the biometricians' great flaws was their inability to look past their population-focused, statistical, gradualist understanding of evolutionary change – which led, in part, to their ignoring developments in cellular biology around 1900. I will argue, on the contrary, that the work of the biometricians was, from its earliest days, fundamentally concerned with connections between (...) statistical patterns of inheritance and the underlying cellular features that gave rise to them. Such work remained current with contemporary knowledge of chromosomes, cytology, and development; in this article, I explore the first case. The biometricians were thus well positioned to understand the relationship between the patterns of Mendelian inheritance and the statistical distributions with which they primarily occupied themselves. Ignorance of this connection, then, is not the reason why they rejected Mendelism. Further, both Galton and Weldon – though each in their own unique way – decided to turn to biological detail as a way to better justify the generality of their statistical approaches to heredity. Perhaps paradoxically, then, for these biometricians, detail offered an approach to theoretical generality. (shrink)

The knowledge of the history of a subject stimulates understanding. As we study how other people have made scientific breakthroughs, we develop the breadth of imagination that would inspire us to make new discoveries of our own. This perspective certainly applies to the teaching of genetics as hallmarked by the pea experiments of Mendel. Common questions students have in reading Mendel’s paper for the first time is how it compares to other botanical, agricultural, and biological texts from the early and (...) mid-nineteenth centuries; and, more precisely, how Mendel’s approach to, and terminology for debating, topics of heredity compare to those of his contemporaries? Unfortunately, textbooks are often unavailing in answering such questions. It is very common to find an introduction about heredity in genetic textbooks covering Mendel without mentions of preceding breeding experiments carried out in his alma mater. This does not help students to understand how Mendel came to ask the questions he did, why he did, or why he planned his pea studies the way he did. Furthermore, the standard textbook “sketch” of genetics does not allow students to consider how discoveries could have been framed and inspired so differently in various parts of the world within a single historical time. In our review we provide an extended overview bridging this gap by showing how different streams of ideas lead to the eventual foundation of particulate inheritance as a scientific discipline. We close our narrative with investigations on the origins of animal and plant breeding in Central Europe prior to Mendel in Kőszeg and Brno, where vigorous debates touched on basic issues of heredity from the early eighteenth-century eventually reaching a pinnacle coining the basic questions: What is inherited and how is it passed on from one generation to another? (shrink)

It has been widely received that one of Gregor Mendel’s most important contributions to the history of genetics is his novel work on developmental information (for example, the proposal of the famous Mendelian ratios like 1:2:1, 3:1, and 9:3:3:1). This view is well evidenced by the fact that much of early Mendelians’ work in the 1900s focuses on the retrodiction (viz. the re-analysis of the pre-exist data with Mendel’s approach). However, there is no consensus on what Mendel meant by development (...) (Entwicklung). Nor is there an agreement on the interpretation of Mendel’s laws of developmental series (Entwicklungsreihe). This chapter revisits Mendel’s notions of development and developmental series. Firstly, I argue that Mendel’s use of development is greatly influenced by Gärtner’s. Secondly, I show Mendel’s work on developmental series are novel and important for its new ways of experimentation, conceputalisation, and analysis. Thirdly, I argue that Mendel’s laws of developmental information were not about heredity. (shrink)

Historiographical analyses of the development of genetics in the first decade of the 20th century have been to a great extent framed in the context of the Mendelian-Biometrician controversy. Much has been discussed on the nature, origin, development, and legacy of the controversy. However, such a framework is becoming less useful and fruitful. This paper challenges the traditional historiography framed by the Mendelian-Biometrician distinction. It argues that the Mendelian-Biometrician distinction fails to reflect the theoretical and methodological diversity in the controversy. (...) It also argues that that the Mendelian-Biometrician distinction is not helpful to make a full understanding of the development of genetics in the first decade of the twentieth century. (shrink)

This book offers an integrated historical and philosophical examination of the origin of genetics. The author contends that an integrated HPS analysis helps us to have a better understanding of the history of genetics, and sheds light on some general issues in the philosophy of science. This book consists of three parts. It begins with historical problems, revisiting the significance of the work of Mendel, de Vries, and Weldon. Then it turns to integrated HPS problems, developing an exemplar-based analysis of (...) the development and the progress in early genetics. Finally, it discusses philosophical problems: conceptual change, evidence, and theory choice. Part I lays out a new historiography, serving as a basis for the discussions in part II and part III. Part II introduces a new integrated HPS method to analyse and interpret the historiography in Part I and to re-examine the philosophical issues in Part III. Part III develops new philosophical accounts which will in turn make a better sense of the history of scientific practice more generally. This book provides a practical defence of integrated HPS: the best way to defend integrated HPS is to do it. (shrink)

Alexander Bird indicates that the significance of Thomas Kuhn in the history of philosophy of science is somehow paradoxical. On the one hand, Kuhn was one of the most influential and important philosophers of science in the second half of the twentieth century. On the other hand, nowadays there is little distinctively Kuhn’s legacy in the sense that most of Kuhn’s work has no longer any philosophical significance. Bird argues that the explanation of the paradox of Kuhn’s legacy is that (...) Kuhn took a direction opposite to that of the mainstream of the philosophy of science in his later academic career. This paper aims to provide a new way to understand and develop Kuhn’s legacy by revisiting the development of Kuhn’s philosophy of science in 1970s and proposing a new account of exemplar. Firstly, I propose my diagnosis of Kuhn’s “wrong turning” by identifying Kuhn’s two novel contributions: the introduction of paradigm and the proposal of the incommensurability thesis. Secondly, I argue that Kuhn made a conceptual/terminological turn from paradigm to theory, which undermined Kuhn’s novel contributions. Thirdly, I propose a new articulation of exemplar and propose an exemplar-based approach to analysing the history of science. Finally, I show how the exemplar-based approach can be applied to analyse the history of science by my case study of the early development of genetics. (shrink)

Trying to understand the genome with the classical philosophers. ISBN 978-84-686-6311-1, Bubok, 2015.This book cannot be download at Philpapers due to its 240 MB size . It can be read and download at the web Scribd.

As many of the papers in this Special Symposium Issue discuss, by the 21st century we have moved well beyond the notion of a gene as a single particulate unit coding for a given protein, or especially a single phenotypic trait. Yet notions of genes as some kind of single, particulate entity still persist, especially in textbooks and writings about genetics for the general public. To understand this disjunct between the professional geneticist’s view of genes and their complex interactions, and (...) the more widespread public understanding of genes as distinct entities, I thought it might be useful to look back 150 years or more to the origins of the gene concept, to the origins of Mendelian genetics itself .. (shrink)

On the current fashion to look after a previous universe to explain the laws of our Universe.Esperando al nuevo Aristóteles, regreso a Henri Bergson y el "Parménides", el otro universo de Plotino. In Spanish.

A briefing of the book "Darwinland" , America Star, 2014.

This research was carried out in order to verify by simulation Mendel’s laws and seek for the clarification, from the author’s point of view, the Mendel-Fisher controversy. It was demonstrated from: the experimental procedure and the first two steps of the Hardy-Weinberg law, that the null hypothesis in such experiments is absolutely and undeniably true. Consequently, repeating hybridizing experiments as those showed by Mendel, it makes sense to expect a highly coincidence between the observed and the expected cell frequencies. By (...) simulation, 30 random samples were generated with size equal to the number of observations reported by Mendel for his single trait trial, in this case, seed shape; assuming complete dominance, with genes A and a; likewise, it was simulated the results for the experiment with two traits, segregating in separate chromosomes, in this case seed shape, as before, and albumen color, with genes B and b, both loci with complete dominance. In the case of a single trait, the data only showed evidence for rejecting the null hypothesis (Ho ) in 1/30 samples, with (P<0.05). In the case of the 30 samples of the two traits experiment, (Ho ) was rejected only on 3/30 times, when it was set a = 0.05. In both simulations there was a high correspondence between the observed and expected cell frequencies, which is simply due to the fact that (Ho ) is true, and under these conditions, that is what would to expect. It was concluded, that Mendel had no reason to manipulate his data in order to make them to coincide with his beliefs. Therefore, in experiment with a single trait, and in experiments with two traits assuming complete dominance, segregation ratios are 3:1; and 9:3:3:1, respectively. Consequently, Mendel’s laws, under the conditions as were described are absolutely valid and universal. (shrink)

The aim of this article is to contribute to the discussion about the so-called “empirical claim” and “empirical basis” of theory testing. First, the proposals of reconceptualization of the standard notions of partial potential model, intended application and empirical claim of a theory made by Balzer (1982, 1988, 1997a, 1997b, 2006, Balzer, Lauth & Zoubek 1993) and Gähde (1996, 2002, 2008) will be first discussed. Then, the distinction between “global” and “local empirical basis” will be introduced, linking it with that (...) of “global” and “local or particular empirical claim”. After that, following Balzer (1997a), along the lines of Suppes (1962), I will present a way in which what count as ‘data’ for a theory can be modeltheoretically represented and conceptualized. Finally, the proposed analysis will be exemplified with the case of classical genetics (reconstructed in Balzer & Lorenzano 2000, Lorenzano, 1995, 2000, 2002). (shrink)

The aim of the present paper is to contribute to the discussion on the constitutive a priori in science by linking it with the discussion on scientific laws and theories, in such a way to show how the different senses of the notion of constitutive a priori are not incompatible to each other and that they can be precised in a unified, though differentiated, manner.

A rereading of the American scientific literature on sex determination from 1902 to 1926 leads to a different understanding of the construction of the Mendelian‐chromosome theory after 1910. There was significant intellectual continuity, which has not been properly appreciated, underlying this scientific “revolution.” After reexamining the relationship between the ideas of key scientists, in particular Edmund B. Wilson and Thomas Hunt Morgan, I argue that, contrary to the historical literature, Wilson and Morgan did not adopt opposing views on Mendelism and (...) sex determination. Rather, each preferred a non‐Mendelian explanation of the determination of sex. Around 1910, both integrated the Mendelian and non‐Mendelian theories to create a synthetic theory. One problem was the need to avoid an overly deterministic view of sex while also accepting the validity of Mendelism. Morgan’s discovery of mutations on the X chromosome takes on different significance when set in the context of the debate about sex determination, and Calvin Bridges’s work on sex determination is better seen as a development of Morgan’s ideas, rather than a departure from them. Conclusions point to the role of synthesis within fields as a way to advance scientific theories and reflect on the relationship between synthesis and explanatory “pluralism” in biology. (shrink)

Supervenience is mostly conceived of as a purely philosophical concept. Nevertheless, I will argue, it played an important and very fruitful inferential role in classical genetics. Gregor Mendel assumed that phenotypic traits supervene on underlying factors, and this assumption allowed him to successfully predict and explain the phenotypical regularities he had experimentally discovered. Therefore it is interesting to explicate how we reason about supervenience relations. I will tackle the following two questions. Firstly, can a reliable method (a logic) be found (...) for infenfog supervenience claims from data? Secondly, can a reliable method (a logic) be found to empirically test supervenience claims? I will answer these questions within the framework of the adaptive logics programme. (shrink)

In this paper I discuss the problem of scientific laws in general and laws of biology in particular. After reviewing the debate about the existence of laws in biology, I examine the subject under the light of the structuralist notion of a fundamental law and argue for the law of matching as the fundamental law of genetics.

In this paper, I discuss the problem of scientific laws in general and laws of biology in particular. After reviewing the debate around the existence of laws in biology, I examine the subject in the light of the structuralist notion of a fundamental law and argue for the law of matching as the fundamental law of genetics.

In science, it sometimes occurs that an event is directly observed, and on other occasions that it is not directly observed but one can make the unambiguous inference that it has occurred. Is there any difference concerning the analysis of data arising from these two situations? In this note we show that there is such a difference in one case arising frequently in genetics. The difference derives from the fact that the ability to make the unambiguous inference arises only from (...) a restricted form of data. (shrink)

Taking as starting point Kuhn’s analysis of science textbooks and its application to Sinnott and Dunn’s (1925), it will be discussed the problem of the existence of laws in biology. In particular, it will be showed, in accordance with the proposals of Darden (1991) and Schaffner (1980, 1986, 1993), the relevance of the exemplars, diagrammatically or graphically represented, in the way in which is carried out the teaching and learning process of classical genetics, inasmuch as the information contained in them, (...) indispensable for the right development of that process, exceeds the information contained in the “laws” linguistically articulated and presented in the textbooks. However, it will be maintained that the information is implicit in the law that according to the structuralist concept of fundamental law and the reconstruction of genetics presented by Balzer & Dawe (1990), and later developed by Balzer & Lorenzano (1997) and Lorenzano (1995, 2000, 2002a) could be considered the fundamental law of classical genetics,the law of matching, clearly identified in this paper. (shrink)

I present an account of classical genetics to challenge theory-biased approaches in the philosophy of science. Philosophers typically assume that scientific knowledge is ultimately structured by explanatory reasoning and that research programs in well-established sciences are organized around efforts to fill out a central theory and extend its explanatory range. In the case of classical genetics, philosophers assume that the knowledge was structured by T. H. Morgan’s theory of transmission and that research throughout the later 1920s, 30s, and 40s was (...) organized around efforts to further validate, develop, and extend this theory. I show that classical genetics was structured by an integration of explanatory reasoning and investigative strategies . The investigative strategies, which have been overlooked in historical and philosophical accounts, were as important as the so-called laws of Mendelian genetics. By the later 1920s, geneticists of the Morgan school were no longer organizing research around the goal of explaining inheritance patterns; rather, they were using genetics to investigate a range of biological phenomena that extended well beyond the explanatory domain of transmission theories. Theory-biased approaches in history and philosophy of science fail to reveal the overall structure of scientific knowledge and obscure the way it functions.Author Keywords: Investigation; Genetic approach; Structure of knowledge; Classical genetics. (shrink)

The prevailing concept in modern cognitive neuroscience is that cognitive functions are performed predominantly at the network level, whereas the role of individual neurons is unlikely to extend beyond forming the simple basic elements of these networks. Within this conceptual framework, individuals of outstanding cognitive abilities appear as a result of a favorable configuration of the microarchitecture of the cognitive-implicated networks, whose final formation in ontogenesis may occur in a relatively random way. Here I suggest an alternative concept, which is (...) based on neurological data and on data from human behavioral genetics. I hypothesize that cognitive functions are performed mainly at the intracellular, probably at the molecular level. Central to this hypothesis is the idea that the neurons forming the networks involved in cognitive processes are complex elements whose functions are not limited to generating electrical potentials and releasing neurotransmitters. According to this hypothesis, individuals of outstanding abilities are so due to a lucky combination of specific genes that determine the intrinsic properties of neurons involved in cognitive functions of the brain. (shrink)

We present a reconstruction of so-called classical, formal or Mendelian genetics using a notation which we believe is more legible than that of earlier accounts, and lends itself easily to computer implementation, for instance in PROLOG. By drawing from, and emending, earlier work of Balzer and Dawe (1986,1997), the present account presents the three most important lines of development of classical genetics: the so-called Mendel's laws, linkage genetics and gene mapping, in the form of a theory-net. This shows that the (...) set theoretic representation format used in the structuralist approach to the philosophy of science also applies to the domain of genetic theories. There construction is intended to lend more clarity to theme thodological, philosophical and didactical discussions of the foundations of genetics, and on the other hand to defend a formally, logically minded view of theories which seems to have become contested through the work of Feyerabend, Kuhn and Kitcher. (shrink)

This article presents a reconstruction of the so-called classical, formal or Mendelian genetics, which is intended to be more complete and adequate than existing reconstructions. This reconstruction has been carried out with the instruments, duly modified and extended with respect to the case under consideration, of the structuralist conception of theories. The so-called Mendel’s Laws, as well as linkage genetics and gene mapping are formulated in a precise manner while the global structure of genetics is represented as a theory-net. These (...) results are of methodological, philosophical and didactical relevance. (shrink)

The aim of the present communication is to contribute to the discussion about the existence of laws in biology. In order of it the argumentation of J.J.C. Smart against their existence and the discussion of it made by M. Ruse and R. Munson are first reconstructed. The examination of this controversy shows that, despite of the differences between the first of the authors mentioned and the other two in relation to the problem of laws in biology, the three share the (...) assumption according to which in the case that there are laws (in strict sense or fundamental) in genetics, they must be some of the so-called “Mendel’s laws”. In the present communication, and from a revision of the metascientific concept of fundamental law, the above assumption is questioned, proposing an alternative analysis, based on a structuralist reconstruction of genetics. (shrink)

The present paper is framed within one of the predominant currents of contemporary philosophy of science, which is based in case studies, in order to construct a solid, non-speculative, metatheory. In this paper classical genetics is formally analized and reconstructed with the instruments, duly modified and extended in accordance with the considered case, of the structuralist view of theories, in such a way that that theory can be characterized as a refinement of an earlier introduced model of genetics, which determines (...) the fundamental traits of any genetical model. Finally, from the reconstruction of classical genetics, the so-called “mendelism” is formally characterized trying to do justice, and to precise, some recent results in the historiography of genetics. (shrink)

This Ph.D. thesis provides a pilosophical account of the structure of the evolutionary synthesis of the 1930s and 40s. The first, more historical part analyses how classical genetics came to be integrated into evolutionary thinking, highlighting in particular the importance of chromosomal mapping of Drosophila strains collected in the wild by Dobzansky, but also the work of Goldschmidt, Sumners, Timofeeff-Ressovsky and others. The second, more philosophical part attempts to answer the question wherein the unity of the synthesis consisted. I argue (...) that it exemplifies a weak of form of explanatory unification. (shrink)

Der orthodoxen Interpretation zufolge wird die Genetik als eine Disziplin dargestellt, deren Geschichte (von ihrem vermuteten Ursprung mit dem Werk Mendels an über die Werke der sogenannten «Wiederentdecker» de Vries, Correns und Tschermak und des englischen Mendelianers Bateson bis hin zur Arbeit Morgans) kontinuierlich, kumulativ und linear verlaufen sei. Im ersten Teil des Buches wird hingegen die Diskontinuität dieses Prozesses betont. Innerhalb der strukturalistischen Auffassung wissenschaftlicher Theorien wird die klassische Genetik im zweiten Teil in einer Weise rekonstruiert und formal analysiert, (...) die den im ersten Teil erarbeiteten Ergebnissen gerecht wird. (shrink)

It is argued that de Vries did not see Mendel's paper until 1900, and that, while his own theory of inheritance may have incorporated the notion of independent units, this pre-Mendelian formulation was not the same as Mendel's since it did not apply to paired hereditary units. Moreover, the way in which the term ‘segregation’ has been applied in the secondary literature has blurred the distinction between what is explained and the law which facilitates explanation.