Whole-exome sequencing revealed a likely pathogenic variant in NF1 causing neurofibromatosis type I and Arrhythmogenic Cardiomyopathy

BACKGROUND

Neurofibromatosis type I (NF1) is a genetic disorder characterized by the tumor's development in nerve tissue. Complications of NF1 can include pigmented lesions, skin neurofibromas, and heart problems such as cardiomyopathy. In this study, we performed whole-exome sequencing (WES) on an Iranian patient with NF1 to identify the genetic cause of the disease.

METHODS

Following clinical assessment, WES was used to identify genetic variants in a family with a son suffering from NF1. No symptomatic manifestations were observed in other family members. In the studied family, in silico and segregation analysis were applied to survey candidate variants.

RESULTS

Clinical manifestations were consistent with arrhythmogenic cardiomyopathy (ACM). WES detected a likely pathogenic heterozygous missense variant, c.3277G > A:p.Val1093Met, in the NF1 gene, confirmed by PCR and Sanger sequencing. The patient's parents and brother had a normal sequence at this locus.

CONCLUSIONS

Although there is no cure for NF1, genetic tests, such as WES, can detect at-risk asymptomatic family members. Furthermore, cardiac evaluation could also help these patients before heart disease development.

William Boven's 1915 thesis "Similarity and Mendelism in the heredity of dementia praecox and manic-depressive insanity"

Boven published, in 1915, his MD thesis at the University of Lausanne in which he examined 60 3- to 4-generation pedigrees ascertained from admitted patients with dementia praecox (DP) and manic-depressive insanity (MDI). He asked three questions: (i) were DP and MDI hereditary? (ii) were they the same or distinct conditions? and (iii) were they Mendelian disorders? Based on the rarity of environmental precipitants severe enough to cause disorder onset and the pattern of disorders in relatives, Boven concluded that both disorders were inherited. He found that MDI largely ran in families through direct transmission across generations while DP was only common in collateral relatives. Both pedigrees contained a substantial number of "psychopathic" (personality disordered) relatives in which DP and MDI pedigrees typically had, respectively, paranoid, and dysthymic/cyclothymic features. Boven concludes that their inheritance is largely distinct but not exclusive, as some pedigrees contained cases of both disorders. With assistance from Wilhelm Weinberg, Boven applied algebraic models with proband correction to rates of DP and MDI in sibships and found the results inconsistent with Mendelian transmission. His study represents among the first examinations, using "modern" methods, of the familial relationship between DP and MDI and the first published in French.

"At a Glance:" The Role of Diagrammatic Representations in Eugenics Appropriations of the "Infamous Juke Family"

The case of the Juke family is one of the most notable episodes of the history of eugenics in the USA. The Jukes were initially brought to the fore in the 1870s by a famous investigation that aimed at estimating the interplay of heredity and environment in determining the problems of poverty and crime. This inquiry triggered a harsh confrontation between two polar interpretations of the study, an "environmentalist" one and a "hereditarian" one. It was with the later reassessment of the case made by the Eugenics American Office (ERO) in the 1910s that the controversy was considered closed with the victory of the eugenicists' hereditarian stance. As a result, the family was made a living proof of the alleged hereditary nature of crime and pauperism and a case study in support of the eugenicists' plea for the sterilization of people deemed the bearers of hereditary defectiveness. In this article, I explore the role played by pedigrees and other diagrammatic representations in the eugenicists' appropriation of the meaning of the case of the Juke family and the role played by this appropriation in asserting the superiority of the ERO's method of work over rival approaches.

Ryssia Wolfsohn's 1907 dissertation on "the heredity of dementia praecox"

In the 19th century, psychiatric genetic studies typically utilized a generic category of "insanity." This began to change after 1899, with the publication of Kraepelin's 6th edition containing, among other disorders, his mature concept of dementia praecox (DP). We here review an article published by Ryssia Wolfsohn in 1907 from her dissertation at the University of Zurich entitled "Die Heredität bei Dementia praecox" (The Heredity of Dementia Praecox). This work, performed under the supervision of E. Bleuler, was to our knowledge the first formal genetic study of the then new diagnosis of DP. She investigated 550 DP probands admitted to the Burghölzli hospital with known information about their "heredity burden." For most probands, she had information on parents, siblings, grandparents, and aunts/uncles. Of these patients, only 10% had no psychiatric illness in their families. In the remaining probands, she found rates of the four major categories of psychopathology she investigated: mental illness-56%, nervous disorders-19%, peculiar personalities 12% and alcoholism 13%. Her most novel analyses compared either total familial burden or burden of her four forms of mental disorders on her DP probands divided by subtype and outcome. In neither of these analyses, did she find significant differences.

Heredity of Schizophrenia in India: A 1928 debate

Shaw, a British psychiatrist working in India, observed that the incidence of Schizophrenia was higher among a community of Parsis as compared to other ethnic groups. He published his findings in two British journals. The paper drew responses from two other psychiatrists. The debate is examined in colonial context during which occurred and some implications for contemporary research.

Heredity of pregnancy-related pelvic girdle pain in Sweden

INTRODUCTION

Pelvic girdle pain during and after pregnancy is a major public health problem with significant daily problems for affected women and their families. There is now accumulating evidence that pregnancy-related pelvic girdle pain originates from the sacroiliac joints and the pubic symphysis as well as their extra-articular ligaments. However, the heritability of the disease remains to be determined. We hypothesized that there is an increased familial risk of pregnancy-related pelvic girdle pain.

MATERIAL AND METHODS

A population-based national database linkage registry study of approximately 9.3 million individuals within 4.2 million families in Sweden with a recruitment period from 1997 to 2018. The Swedish Multi-generation register was used to find female pairs of twins, full siblings, half-siblings and first cousins where both in the pairs had a completed pregnancy. The outcome measure was diagnosis of pregnancy-related pelvic girdle pain (International Classification of Diseases-10 O26.7 [1997-2018]) in the first pregnancy. Data was obtained from the Swedish Hospital Discharge Register, the Swedish Outpatient Care Register, the Swedish Medical Birth Register, the Primary Healthcare Register, and Medical Treatment Register. Cox regression analysis was used to calculate adjusted estimated effect of the exposure variable familial history of pregnancy-related pelvic girdle pain on the outcome variable pregnancy-related pelvic girdle pain at first birth.

RESULTS

From the registers, 1 010 064 women pregnant with their first child within 795 654 families were collected. In total, 109 147 women were diagnosed with pregnancy-related pelvic girdle pain. The adjusted hazard ratio for a familial risk of pregnancy-related pelvic girdle pain was 2.09 (95% CI 1.85-2.37) among twins (monozygotic and dizygotic), 1.78 (95% CI 1.74-1.82) in full siblings, 1.16 (95% CI 1.06-1.28) in half-siblings from the mother, 1.09 (95% CI 1.024-1.16) in half-siblings from the father and 1.09 (95% CI 1.07-1.12) in first cousins.

CONCLUSIONS

This nationwide observational study showed a familial clustering of pregnancy-related pelvic girdle pain. The hazard ratio for the condition was associated with the degree of relatedness, suggesting that heredity factors contribute to the development of pregnancy-related pelvic girdle pain. There is no causal treatment available for pregnancy-related pelvic girdle pain and further studies are now encouraged to clarify the specific genetic factors that contribute to the disease and for future targeted interventions.

Irma Weinberg's 1928 paper "on the problem of the determination of heredity prognosis: The risk in the cousins of schizophrenics"

Irma Weinberg, a German-Jewish Neuropsychiatrist/Physician, authored the fourth report from the German Research Institute for Psychiatry in Munich examining the risk for dementia praecox (DP) in particular relatives of DP probands, here first-cousins. She examined 977 cousins of 54 DP probands and found a best-estimate risk of 1.4%. She conducted within-study analyses, showing a much higher risk for DP in the siblings than cousins of DP probands. She studied DP-related personalities showing a familial link between these conditions and risk for DP. She demonstrated that the risk for DP in cousins was impacted substantially by the distribution, in ancestors, of psychosis and personality abnormalities. After completing work on this article, Weinberg worked in private practice in Frankfurt, emigrating to the Netherlands in 1934, where she worked at a Jewish psychiatric hospital. In 1943, German occupiers evacuated the hospital, transporting the patients and staff, either directly to Auschwitz or, like Weinberg, to the Westerbork transit camp. On September 4, 1944, Dr. Weinberg was transported to Theresienstadt and soon thereafter to Auschwitz, where she was murdered at the age of 53. Her history raises painful questions about the relationship between genetic studies of psychiatric illness in prewar Germany and the Holocaust.

"Not by a Decree of Fate:" Ellen Richards, Euthenics, and the Environment in the Progressive Era

In 1904, Ellen Richards introduced "euthenics." By 1912, Lewellys Barker, director of medicine and physician-in-chief at Johns Hopkins Hospital, would tell the New York Times that the "task of eugenics" and the "task of euthenics" was the "Task for the Nation." Alongside the emergence of hereditarian eugenics, where fate was firmly rooted in heredity, this article places euthenics into the same Progressive Era demands for the scientific management over environmental issues like life and labor, health and hygiene, sewage and sanitation. I argue that euthenics not only heralded women as leaders in the quest for what Richards and eugenicists termed "racial improvement," but also aimed to make reforms through environmental and educational changes rather than hereditary interventions. Seeking to recuperate the figure of Ellen Richards in the history of science, I place Richards and her euthenics more into the debate over eugenics rather than over the emergence of home economics. Building on the work of Donald Opitz, Staffan Bergwik, and Brigette Van Tiggelen, this article shows, first, how Richards' career threads the needle between the home and the laboratory as sites of science making, not as separate spheres but as overlapping realms, and helps recover how domestic concerns shaped the focus of the life sciences. Second, this article shows how euthenics shaped eugenics by looking at the writings of American eugenicists Charles Davenport, Paul Popenoe, and David Starr Jordan. Third, the article describes how euthenics took root in new academic departments of domestic science, home economics, and departments child welfare and family life in the 1920 and 1930s, most notably the department of euthenics at the Kansas State Agricultural College from 1926 and the Institute of Euthenics at Vassar College after 1923.

How do experts in psychiatric genetics view the clinical utility of polygenic risk scores for schizophrenia?

Polygenic risk scores (PRS) are promising for identifying common variant-related inheritance for psychiatric conditions but their integration into clinical practice depends on their clinical utility and psychiatrists' understanding of PRS. Our online survey explored these issues with 276 professionals working in psychiatric genetics (RR: 19%). Overall, participants demonstrated knowledge of how to interpret PRS results. Their performance on knowledge-based questions was positively correlated with participants' self-reported familiarity with PRS (r = 0.21, p = 0.0006) although differences were not statistically significant (Wald Chi-square = 3.29, df = 1, p = 0.07). However, only 48.9% of all participants answered all knowledge questions correctly. Many participants (56.5%), especially researchers (42%), indicated having at least occasional conversations about the role of genetics in psychiatric conditions with patients and/or family members. Most participants (62.7%) indicated that PRS are not yet sufficiently robust for assessment of susceptibility to schizophrenia; most significant obstacles were low predictive power and lack of population diversity in available PRS (selected, respectively, by 53.6% and 29.3% of participants). Nevertheless, 89.8% of participants were optimistic about the use of PRS in the next 10 years, suggesting a belief that current shortcomings could be addressed. Our findings inform about the perceptions of psychiatric professionals regarding PRS and the application of PRS in psychiatry.

Heredity as a problem. On Claude Bernard's failed attempts at resolution

Heredity has been dismissed as an insignificant object in Claude Bernard's physiology, and the topic is usually ignored by historians. Yet, thirty years ago, Jean Gayon demonstrated that Bernard did elaborate on the subject. The present paper aims at reassessing the issue of heredity in Claude Bernard's project of a "general physiology". My first claim is that Bernard's interest in heredity was linked to his ambitious goal of redefining general physiology in relation to morphology. In 1867, not only was morphology included within experimental physiology, but it also theoretically grounded physiological investigations. By 1878, morphology and physiology were considered as completely independent sciences, and only the latter was perceived as suitable to experimentation. My second claim is that this reversal reflected the existence of two opposite attitudes towards heredity. In the late 1860s, Bernard was convinced that heredity would soon be accessible to experimental manipulation and that new species would be produced in the laboratory exactly like organic chemistry succeeded to do for raw bodies. Ten years later, he ascertained that this was impossible. My third claim is that Bernard was epistemologically ill-equipped to address the issue of heredity. Bernard was strongly committed to a general reasoning scheme that acknowledged only three categories: determining conditions, constant laws and phenomena. This scheme was a key factor in his successes as a physiologist who was able to capture new mechanisms in living bodies. Nonetheless, it also prevented him from understanding how time and history could be endowed with a causal action that cannot be reduced to timeless parameters.

Species Transformation and Social Reform: The Role of the Will in Jean-Baptiste Lamarck's Transformist Theory

Jean-Baptiste Lamarck is well known as a pre-Darwinian proponent of evolution. But much of what has been written on Lamarck, on his 'Lamarckian' belief in the inheritance of acquired characters, and on his conception of the role of the will in biological development mischaracterizes his views. Indeed, surprisingly little in-depth analysis has been published regarding his views on human physiology and development. Further, although since Robert M. Young's signal 1969 essay on Malthus and the evolutionists, Darwin scholars have sought to place Darwin's work in its social and political context, this has yet to be done adequately for Lamarck. Here I address this gap. I argue that the will was of particular importance to Lamarck's social commentary and his hopes for the transformation of the French people and nation. Further, I argue that if we are to really grasp Lamarck's ideas and intentions we need to contextualize his works in relation to prevailing debates in France about the physiology of mind and morals and the future of the nation.

New historical and philosophical perspectives on quantitative genetics

The aim of this virtual special issue is to bring together philosophical and historical perspectives to address long-standing issues in the interpretation, utility, and impacts of quantitative genetics methods and findings. Methodological approaches and the underlying scientific understanding of genetics and heredity have transformed since the field's inception. These advances have brought with them new philosophical issues regarding the interpretation and understanding of quantitative genetic results. The contributions in this issue demonstrate that there is still work to be done integrating old and new methodological and conceptual frameworks. In some cases, new results are interpreted using assumptions based on old concepts and methodologies that need to be explicitly recognised and updated. In other cases, new philosophical tools can be employed to synthesise historical quantitative genetics work with modern methodologies and findings. This introductory article surveys three general themes that have dominated philosophical discussion of quantitative genetics throughout history: (1) how methodologies have changed and transformed our knowledge and interpretations; (2) whether or not quantitative genetics can offer explanations relating to causation and prediction; and (3) the importance of defining the phenotypes under study. We situate the contributions in this virtual special issue within a historical framework addressing these three themes.

Transgenerational Epigenetic Inheritance of Traumatic Experience in Mammals

In recent years, we have seen an increasing amount of evidence pointing to the existence of a non-genetic heredity of the effects of events such as separation from parents, threat to life, or other traumatising experiences such as famine. This heredity is often mediated by epigenetic regulations of gene expression and may be transferred even across several generations. In this review, we focus on studies which involve transgenerational epigenetic inheritance (TEI), with a short detour to intergenerational studies focused on the inheritance of trauma or stressful experiences. The reviewed studies show a plethora of universal changes which stress exposure initiates on multiple levels of organisation ranging from hormonal production and the hypothalamic-pituitary-adrenal (HPA) axis modulation all the way to cognition, behaviour, or propensity to certain psychiatric or metabolic disorders. This review will also provide an overview of relevant methodology and difficulties linked to implementation of epigenetic studies. A better understanding of these processes may help us elucidate the evolutionary pathways which are at work in the course of emergence of the diseases and disorders associated with exposure to trauma, either direct or in a previous generation.

From correlation to causation: The new frontier of transgenerational epigenetic inheritance

While heredity is predominantly controlled by what deoxyribonucleic acid (DNA) sequences are passed from parents to their offspring, a small but growing number of traits have been shown to be regulated in part by the non-genetic inheritance of information. Transgenerational epigenetic inheritance is defined as heritable information passed from parents to their offspring without changing the DNA sequence. Work of the past seven decades has transitioned what was previously viewed as rare phenomenology, into well-established paradigms by which numerous traits can be modulated. For the most part, studies in model organisms have correlated transgenerational epigenetic inheritance phenotypes with changes in epigenetic modifications. The next steps for this field will entail transitioning from correlative studies to causal ones. Here, we delineate the major molecules that have been implicated in transgenerational epigenetic inheritance in both mammalian and non-mammalian models, speculate on additional molecules that could be involved, and highlight some of the tools which might help transition this field from correlation to causation.

Recruitment of CTCF to an Fto enhancer is responsible for transgenerational inheritance of BPA-induced obesity

The mechanisms by which environmentally-induced epiphenotypes are transmitted transgenerationally in mammals are poorly understood. Here we show that exposure of pregnant mouse females to bisphenol A (BPA) results in obesity in the F2 progeny due to increased food intake. This epiphenotype can be transmitted up to the F6 generation. Analysis of chromatin accessibility in sperm of the F1-F6 generations reveals alterations at sites containing binding motifs for CCCTC-binding factor (CTCF) at two cis-regulatory elements (CREs) of the Fto gene that correlate with transmission of obesity. These CREs show increased interactions in sperm of obese mice with the Irx3 and Irx5 genes, which are involved in the differentiation of appetite-controlling neurons. Deletion of the CTCF site in Fto results in mice that have normal food intake and fail to become obese when ancestrally exposed to BPA. The results suggest that epigenetic alterations of Fto can lead to the same phenotypes as genetic variants.

"Batesonian Mendelism" and "Pearsonian biometry": shedding new light on the controversy between William Bateson and Karl Pearson

This paper contributes to the ongoing reassessment of the controversy between William Bateson and Karl Pearson by characterising what we call "Batesonian Mendelism" and "Pearsonian biometry" as coherent and competing scientific outlooks. Contrary to the thesis that such a controversy stemmed from diverging theoretical commitments on the nature of heredity and evolution, we argue that Pearson's and Bateson's alternative views on those processes ultimately relied on different appraisals of the methodological value of the statistical apparatus developed by Francis Galton. Accordingly, we contend that Bateson's belief in the primacy of cross-breeding experiments over statistical analysis constituted a minimal methodological unifying condition ensuring the internal coherence of Batesonian Mendelism. Moreover, this same belief implied a view of the study of heredity and evolution as an experimental endeavour and a conception of heredity and evolution as fundamentally discontinuous processes. Similarly, we identify a minimal methodological unifying condition for Pearsonian biometry, which we characterise as the view that experimental methods had to be subordinate to statistical analysis, according to methodological standards set by biometrical research. This other methodological commitment entailed conceiving the study of heredity and evolution as subsumable under biometry and primed Pearson to regard discontinuous hereditary and evolutionary processes as exceptions to a statistical norm. Finally, we conclude that Batesonian Mendelism and Pearsonian biometry represented two potential versions of a single genetics-based evolutionary synthesis since the methodological principles and the phenomena that played a central role in the former were also acknowledged by the latter-albeit as fringe cases-and conversely.

Cambridge geneticists and the chromosome theory of inheritance: William Bateson, Leonard Doncaster and Reginald Punnett 1879-1940

Early in the 20th century Bateson, Doncaster and Punnett formed a cooperative collective to share research findings on the chromosome theory of heredity (CTH). They cross-bred plants and animals to correlate behaviour of chromosomes and heredity of individual traits. Doncaster was the most enthusiastic proponent of the new theory and worked for years to convince Bateson and Punnett on its relevance to their own research. The two younger biologists collaborated with Bateson, the preeminent geneticist in England. As their own reputations developed, their research findings allied with the consensus on the importance of the CTH by the broader scientific community. After Doncaster's tragic death in 1920, major objections to the theory had been resolved; Bateson and Punnett then utilized the CTH to construct chromosome maps detailing locations of specific genes on particular chromosomes in several different species. The marriage of heredity and cytology enhanced confidence that the theory was an accurate mechanism to explain inheritance in both plants and animals.

Mimush Sheep and the Spectre of Inbreeding: Historical Background for Festetics's Organic and Genetic Laws Four Decades Before Mendel's Experiments in Peas

The upheavals of late eighteenth century Europe encouraged people to demand greater liberties, including the freedom to explore the natural world, individually or as part of investigative associations. The Moravian Agricultural and Natural Science Society, organized by Christian Carl André, was one such group of keen practitioners of theoretical and applied scientific disciplines. Headquartered in the "Moravian Manchester" Brünn (nowadays Brno), the centre of the textile industry, society members debated the improvement of sheep wool to fulfil the needs of the Habsburg armies fighting in the Napoleonic Wars. Wool, as the raw material of soldiers' clothing, could influence the war's outcome. During the early nineteenth century, wool united politics, economics, and science in Brno, where breeders and natural scientists investigated the possibilities of increasing wool production. They regularly discussed how "climate" or "seed" characteristics influenced wool quality and quantity. Breeders and academics put their knowledge into immediate practice to create sheep with better wool traits through consanguineous matching of animals and artificial selection. This apparent disregard for the incest taboo, however, was viewed as violating natural laws and cultural norms. The debate intensified between 1817 and 1820, when a Hungarian veteran soldier, sheep breeder, and self-taught natural scientist, Imre (Emmerich) Festetics, displayed his inbred Mimush sheep, which yielded wool extremely well suited for the fabrication of light but strong garments. Members of the Society questioned whether such "bastard sheep" would be prone to climatic degeneration, should be regarded as freaks of nature, or could be explained by natural laws. The exploration of inbreeding in sheep began to be distilled into hereditary principles that culminated in 1819 with Festetics's "laws of organic functions" and "genetic laws of nature," four decades before Gregor Johann Mendel's seminal work on heredity in peas.

The MIT Press 2021

This is a review essay of two books published in 2021 on the history of human heredity-genetics/genomics investigations-in the Middle East. Both books are structured comparatively. Both books grapple with the many uses of biology in nationalizing projects in the Middle East and the unavoidable tension between these particularizing projects and the scientific claim of biology to universality. Furthermore, both grapple with issues of classifications of humans and their uses in biology: the presumably biological human classifications of race, ethnos, and ancestry, and the properly sociocultural ones, such as historical-traditional, by language, by religion. Combined, the two books offer a keen gaze on the complex entwinement of genetics and nationalism in the Middle East from WWI to the present.

Development and Heredity in the Interwar Period: Hans Spemann and Fritz Baltzer on Organizers and Merogones

This article explores the collaborative research of the Nobel laureate Hans Spemann (1869-1941) and the Swiss zoologist Fritz Baltzer (1884-1974) on problems at the intersection of development and heredity and raises more general questions concerning science and politics in Germany in the interwar period. It argues that Spemann and Baltzer's collaborative work made a significant contribution to the then ongoing debates about the relation between developmental physiology and hereditary studies, although Spemann distanced himself from Drosophila genetics because of his anti-reductionist position. The article analyzes how Spemann framed the issues of heredity in terms of an epigenetic principle in the context of his work on the "organizer," and it explores the experimental dynamics of research on newt merogones carried out by Baltzer in a methodological development of Spemann's constriction experiments. Finally, these research attempts are discussed as part of a broader "prehistory" of the mid-twentieth century cell nuclear transplantation experiments, which provided the basis for later animal cloning.

Of stirps and chromosomes: Generality through detail

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.

Behavioral genetics and genomics: Mendel's peas, mice, and bees

The question of the heritability of behavior has been of long fascination to scientists and the broader public. It is now widely accepted that most behavioral variation has a genetic component, although the degree of genetic influence differs widely across behaviors. Starting with Mendel's remarkable discovery of "inheritance factors," it has become increasingly clear that specific genetic variants that influence behavior can be identified. This goal is not without its challenges: Unlike pea morphology, most natural behavioral variation has a complex genetic architecture. However, we can now apply powerful genome-wide approaches to connect variation in DNA to variation in behavior as well as analyses of behaviorally related variation in brain gene expression, which together have provided insights into both the genetic mechanisms underlying behavior and the dynamic relationship between genes and behavior, respectively, in a wide range of species and for a diversity of behaviors. Here, we focus on two systems to illustrate both of these approaches: the genetic basis of burrowing in deer mice and transcriptomic analyses of division of labor in honey bees. Finally, we discuss the troubled relationship between the field of behavioral genetics and eugenics, which reminds us that we must be cautious about how we discuss and contextualize the connections between genes and behavior, especially in humans.

Gregor Johann Mendel: From peasant to priest, pedagogue, and prelate

Gregor Mendel was an Augustinian priest in the Monastery of St. Thomas in Brünn (Brno, Czech Republic) as well as a civilian employee who taught natural history and physics in the Brünn Modern School. The monastery's secular function was to provide teachers for the public schools across Moravia. It was a cultural, educational, and artistic center with an elite core of friar-teachers with a well-stocked library and other amenities including a gourmet kitchen. It was wealthy, with far-flung holdings yielding income from agricultural productions. Mendel had failed his tryout as a parish priest and did not complete his examination for teaching certification despite 2 y of study at the University of Vienna. In addition to his teaching and religious obligations, Mendel carried out daily meteorological and astronomical observations, cared for the monastery's fruit orchard and beehives, and tended plants in the greenhouse and small outdoor gardens. In the years 1856 to 1863, he carried out experiments on heredity of traits in garden peas regarded as revolutionary today but not widely recognized during his lifetime and until 16 y after his death. In 1868 he was elected abbot of the monastery, a significantly elevated position in the ecclesiastical and civil hierarchy. While he had hoped to be elected, and was honored to accept, he severely underestimated its administrative responsibilities and gradually had to abandon his scientific interests. The last decade of his life was marred by an ugly dispute with civil authorities over monastery taxation.

Darwin’s tales–A content analysis of how evolution is presented in children’s books

In science, certain theories led to a paradigm shift in human being’s approach to explain nature, such as the theory of relativity, the quantum theory, and the theory of evolution. The latter explains the emergence of biodiversity on Earth and all living beings’ relatedness, including humans. Accordingly, evolutionary theory is a central part of scientific literacy. However, scholars have demonstrated that misconceptions emerging in childhood hinder learners from grasping evolutionary processes. Implementing evolution in early science education could enhance scientific ideas as a basis for subsequent learning at school. Currently, children’s literature that deals with evolution is increasing and may enable more children to encounter evolutionary theory before entering school. This explorative study aimed to analyze how children’s books about evolution approach explaining this complex topic to young children in terms of covered contents, underlying concepts and use of language. We conducted (1) a text-based qualitative content analysis of 31 children’s books in the categories of organismal context, evolutionary principles, and misconceptions, and (2) a computer-supported content analysis of 33 word labels concerning (a) scientific terms and (b) verbs expressing evolutionary change. Although evolution is a universal concept, children’s books seem to promote specific contexts such as animal and human evolution. Even though the principle of selection requires an understanding of complex interactions between individuals and environmental factors, this principle was more frequent than the principles variation and inheritance. Phylogenetic history was covered more often than basic evolutionary processes, and evolutionary change was mainly mentioned at the species level over long periods. Besides, most books conveyed misconceptions such as transformationist, teleological or anthropomorphic reasoning. Consequently, books covering evolution may bias children’s first ideas concerning this topic or introduce unscientific ideas. Based on our results, we propose implications for early evolution educators and education researchers.

Genotype error biases trio-based estimates of haplotype phase accuracy

Haplotypes can be estimated from unphased genotype data via statistical methods. When parent-offspring trios are available for inferring the true phase from Mendelian inheritance rules, the accuracy of statistical phasing is usually measured by the switch error rate, which is the proportion of pairs of consecutive heterozygotes that are incorrectly phased. We present a method for estimating the genotype error rate from parent-offspring trios and a method for estimating the bias that occurs in the observed switch error rate as a result of genotype error. We apply these methods to 485,301 genotyped UK Biobank samples that include 898 White British trios and to 38,387 sequenced TOPMed samples that include 217 African Caribbean trios and 669 European American trios. We show that genotype error inflates the observed switch error rate and that the relative bias increases with sample size. For the UK Biobank White British trios, the observed switch error rate in the trio offspring is 2.4 times larger than the estimated true switch error rate (1.4 × 10-3 vs 5.8 × 10-4. We propose an alternate definition of phase error that counts two consecutive switch errors as a single error because back-to-back switch errors arise when a single heterozygote is incorrectly phased with respect to the surrounding heterozygotes. With this definition, we estimate that the average distance between phase errors is 64 megabases in the UK Biobank White British individuals.

Pedigree study of the heredity of copper-associated hepatitis in Dalmatians in Japan

The pedigrees of 3 Dalmatian dogs afflicted with copper-associated hepatitis were investigated to discover the mode of inheritance. A composite family pedigree showed that the 3 affected Dalmatians were related. None of the parents of the affected dogs showed clinical symptoms of liver disease, and the disease had no sex predisposition. The estimated segregation ratio was approximately 3:1 based on surviving littermates. These findings suggested that the copper-associated hepatitis in these Dalmatians was an autosomal recessive mode of inheritance. In addition, some male Dalmatians imported from abroad might have been involved in the occurrence of this disease in Japan.

The ethical gene

In this paper I argue that current law and policy governing germline genetic modification are overly broad and in fact prohibit medical interventions normally considered unobjectionable. The root of the problem lies in the fact law and policy tend to espouse a near categorical ban on medical interventions that alter germline DNA. However, if we pay close attention to the biological mechanisms at play we see that many standard medical interventions result in alterations to DNA that can be transmitted to future generations. The correct focus of policy and regulation thus ought to be determining which kinds of transmissible genetic modifications ought to be permitted, and not whether they should be permitted at all. Given that the scientific classification of biological structures involved in the inheritance of traits is unlikely to be in itself ethically significant, ethicists ought to develop a definition of 'gene' fit for ethical purposes.

Natural selection according to Darwin: cause or effect?

In the 1940s, the 'modern synthesis' (MS) of Darwinism and genetics cast genetic mutation and recombination as the source of variability from which environmental events naturally select the fittest, such 'natural selection' constituting the cause of evolution. Recent biology increasingly challenges this view by casting genes as followers and awarding the leading role in the genesis of adaptations to the agency and plasticity of developing phenotypes-making natural selection a consequence of other causal processes. Both views of natural selection claim to capture the core of Darwin's arguments in On the Origin of Species. Today, historians largely concur with the MS's reading of Origin as a book aimed to prove natural selection the cause (vera causa) of adaptive change. This paper finds the evidence for that conclusion wanting. I undertake to examine the context and meaning of all Darwin's known uses of the phrase vera causa, documenting in particular Darwin's resistance to the pressure to prove natural selection a vera causa in letters written early in 1860. His resistance underlines the logical dependence of natural selection, an unobservable phenomenon, on the causal processes producing the observable events captured by the laws of inheritance, variation, and the struggle for existence, established in Chapters 1-3 of Origin.

Genetics Matters: Voyaging from the Past into the Future of Humanity and Sustainability

The understanding of how genetic information may be inherited through generations was established by Gregor Mendel in the 1860s when he developed the fundamental principles of inheritance. The science of genetics, however, began to flourish only during the mid-1940s when DNA was identified as the carrier of genetic information. The world has since then witnessed rapid development of genetic technologies, with the latest being genome-editing tools, which have revolutionized fields from medicine to agriculture. This review walks through the historical timeline of genetics research and deliberates how this discipline might furnish a sustainable future for humanity.

Whatever happened to reversion?

The idea of 'reversion' or 'atavism' has a peculiar history. For many authors in the late-nineteenth and early-twentieth centuries - including Darwin, Galton, Pearson, Weismann, and Spencer, among others - reversion was one of the central phenomena which a theory of heredity ought to explain. By only a few decades later, however, Fisher and others could look back upon reversion as a historical curiosity, a non-problem, or even an impediment to clear theorizing. I explore various reasons that reversion might have appeared to be a central problem for this first group of figures, focusing on their commitment to a variety of conceptual features of evolutionary theory; discuss why reversion might have then ceased to be an interesting phenomenon; and, finally, close with some more general thoughts about the death of scientific problems.

Humboldt, Darwin, and romantic resonance in science

There have been constant and multiple endeavours to argue for Darwin's both epistemic and practical debt to Romanticism. Almost all of these arguments emphasise Darwin's theoretical and aesthetic associations with Alexander von Humboldt, who, from a prevailing Darwin-centred perspective, is in turn usually oversimplified as an undisputed incarnation of Romanticism. The antagonistic view, however, develops nothing other than another stereotype of Humboldt as an anti-idealistic, pro-French, and even highly Anglophone empiricist naturalist, and accordingly rejects the claim of a romantic Darwin in terms of his Humboldtian inheritance. In this paper, I will first portray a balanced figure of Humboldt in terms of both his critical incorporation of romantic philosophy and the idiosyncratic history of his science. Then, I will thematically compare Darwin with Humboldt and other romantics so as to elucidate Darwin's peculiar appropriation of romantic tenets. Three interrelated romantic themes are examined, along with a discrimination of different senses in which the term romanticism is used: a) the literature-science relation, b) the pursuit of the unity in and through multiplicity, and c) the epistemic role of imagination. On the basis of this triadic dissection, both Humboldt's and Darwin's adherence to and departure from romanticism are reevaluated.

Impact of Endocrine Disruptors upon Non-Genetic Inheritance

Similar to environmental factors, EDCs (endocrine-disrupting chemicals) can influence gene expression without modifying the DNA sequence. It is commonly accepted that the transgenerational inheritance of parentally acquired traits is conveyed by epigenetic alterations also known as “epimutations”. DNA methylation, acetylation, histone modification, RNA-mediated effects and extracellular vesicle effects are the mechanisms that have been described so far to be responsible for these epimutations. They may lead to the transgenerational inheritance of diverse phenotypes in the progeny when they occur in the germ cells of an affected individual. While EDC-induced health effects have dramatically increased over the past decade, limited effects on sperm epigenetics have been described. However, there has been a gain of interest in this issue in recent years. The gametes (sperm and oocyte) represent targets for EDCs and thus a route for environmentally induced changes over several generations. This review aims at providing an overview of the epigenetic mechanisms that might be implicated in this transgenerational inheritance.

Epigenetic Mechanisms Responsible for the Transgenerational Inheritance of Intrauterine Growth Restriction Phenotypes

A poorly functioning placenta results in impaired exchanges of oxygen, nutrition, wastes and hormones between the mother and her fetus. This can lead to restriction of fetal growth. These growth restricted babies are at increased risk of developing chronic diseases, such as type-2 diabetes, hypertension, and kidney disease, later in life. Animal studies have shown that growth restricted phenotypes are sex-dependent and can be transmitted to subsequent generations through both the paternal and maternal lineages. Altered epigenetic mechanisms, specifically changes in DNA methylation, histone modifications, and non-coding RNAs that regulate expression of genes that are important for fetal development have been shown to be associated with the transmission pattern of growth restricted phenotypes. This review will discuss the subsequent health outcomes in the offspring after growth restriction and the transmission patterns of these diseases. Evidence of altered epigenetic mechanisms in association with fetal growth restriction will also be reviewed.

Challenging dogmas: How transgenerational epigenetics reshapes our views on life

The emergence of the field of transgenerational epigenetics inheritance (TEI) has profoundly reshaped our understanding of the relationships between environment, soma, and germ cells as well as of heredity. TEI refers to the changes in chromatin state, gene expression, and/or phenotypes that are transmitted across several generations without involving changes to the DNA sequences. TEI has direct connections with, and feeds from, the fields of molecular biology, genetics, developmental biology, and reproductive biology, among others. However, the expansion of TEI-related research, has profoundly reshaped boundaries within each field and often led to the erosion of theories and concepts considered as tenets of biology. We first explore how the molecularization of biology has shifted the definition of epigenetics to include the notion of heredity and how epigenetics has refined our understanding of the central dogma of biology. The demonstrated transfer of environmental information from soma to germ cell through extracellular vesicles and subsequent alteration of health outcomes in offspring has put a definite end to the long-held principle of the Weismann barrier. TEI has also simultaneously led to the revival of the inheritance of acquired characteristics while further eroding the concept of an epigenetic "blank slate" in mammals. Using an historical framework, and via the exploration of central studies in the field, in this perspective article, we will draw a compelling argument for the revolutionary aspect of TEI in biology.

The synergism hypothesis (revisited): a theory whose time has come?

A major theoretical issue in evolutionary biology over the past two decades has concerned the rise of complexity over time in the natural world, and a search has been underway for "a Grand Unified Theory" - as biologist Daniel McShea characterized it - that is consistent with Darwin's great vision. As it happens, such a theory already exists. It was first proposed many years ago in The Synergism Hypothesis: A Theory of Progressive Evolution, and it involves an economic (or perhaps bioeconomic) theory of complexity. Simply stated, cooperative interactions of various kinds, however they may occur, can produce novel combined effects - synergies - with functional advantages that may, in turn, become direct causes of natural selection. In other words, the Synergism Hypothesis is a theory about the unique combined effects produced by the relationships between things. I refer to it as Holistic Darwinism; it is entirely con - sistent with natural selection theory, properly understood. Because the Synergism Hypothesis was first proposed during a time when the genecentric, neo-Darwinist paradigm was domi nant in evolutionary biology, it was largely overlooked. But times have changed. Biologist Richard Michod has concluded that "cooperation is now seen as the primary creative force behind ever greater levels of complexity and organization in all of biology." And Martin Nowak has called cooperation "the master architect of evolution." Here I will revisit this theory in the light of the many theoretical developments and research findings in recent years that are supportive of it, including the role of symbiogenesis in evolution, the phenomenon of hybridization, lateral gene transfer in prokaryotes, "developmental plasticity" (evo-devo), epigenetic inheritance, the role of behaviour (and teleonomy) in evolution, and gene-culture coevolution. The Synergism Hypothesis is especially relevant to the evolution of humankind.

Modelling the functional genomics of Parkinson's disease in Caenorhabditis elegans: LRRK2 and beyond

For decades, Parkinson's disease (PD) cases have been genetically categorised into familial, when caused by mutations in single genes with a clear inheritance pattern in affected families, or idiopathic, in the absence of an evident monogenic determinant. Recently, genome-wide association studies (GWAS) have revealed how common genetic variability can explain up to 36% of PD heritability and that PD manifestation is often determined by multiple variants at different genetic loci. Thus, one of the current challenges in PD research stands in modelling the complex genetic architecture of this condition and translating this into functional studies. Caenorhabditis elegans provide a profound advantage as a reductionist, economical model for PD research, with a short lifecycle, straightforward genome engineering and high conservation of PD relevant neural, cellular and molecular pathways. Functional models of PD genes utilising C. elegans show many phenotypes recapitulating pathologies observed in PD. When contrasted with mammalian in vivo and in vitro models, these are frequently validated, suggesting relevance of C. elegans in the development of novel PD functional models. This review will discuss how the nematode C. elegans PD models have contributed to the uncovering of molecular and cellular mechanisms of disease, with a focus on the genes most commonly found as causative in familial PD and risk factors in idiopathic PD. Specifically, we will examine the current knowledge on a central player in both familial and idiopathic PD, Leucine-rich repeat kinase 2 (LRRK2) and how it connects to multiple PD associated GWAS candidates and Mendelian disease-causing genes.

Heritable consequences of paternal nicotine exposure: from phenomena to mechanisms†

Our understanding of the interactions between genetic and environmental factors in shaping behavioral phenotypes has expanded to include environment-induced epigenetic modifications and the intriguing possibility of their association with heritable behavioral phenotypes. The molecular basis of heritability of phenotypes arising from environment-induced epigenetic modifications is not well defined yet. However, phenomenological evidence in favor of it is accumulating rapidly. The resurgence of interest has led to focus on epigenetic modification of germ cells as a plausible mechanism of heritability. Perhaps partly because of practical reasons such as ease of access to male germ cells compared to female germ cells, attention has turned toward heritable effects of environmental influences on male founders. Public health implications of heritable effects of paternal exposures to addictive substances or to psycho-social factors may be enormous. Considering nicotine alone, over a billion people worldwide use nicotine-containing products, and the majority are men. Historically, the adverse effects of nicotine use by pregnant women received much attention by scientists and public policy experts alike. The implications of nicotine use by men for the physical and mental well-being of their children were not at the forefront of research until recently. Here, we review progress in the emerging field of heritable effects of paternal nicotine exposure and its implications for behavioral health of individuals in multiple generations.

Identification of SPRY4 as a Novel Candidate Susceptibility Gene for Familial Nonmedullary Thyroid Cancer

Background: The molecular basis of familial nonmedullary thyroid cancer (FNMTC) is still poorly understood, representing a limitation for molecular diagnosis and clinical management. In this study, we aimed to identify new susceptibility genes for FNMTC through whole-exome sequencing (WES) analysis of leukocyte DNA of patients from a highly informative FNMTC family. Methods: We selected six affected family members to conduct WES analysis. Bioinformatic analyses were undertaken to filter and select the genetic variants shared by the affected members, which were subsequently validated by Sanger sequencing. To select the most likely pathogenic variants, several studies were performed, including family segregation analysis, in silico impact characterization, and gene expression (messenger RNA and protein) depiction in databases. For the most promising variant identified, we performed in vitro studies to validate its pathogenicity. Results: Several potentially pathogenic variants were identified in different candidate genes. After filtering with appropriate criteria, the variant c.701C>T, p.Thr234Met in the SPRY4 gene was prioritized for in vitro functional characterization. This SPRY4 variant led to an increase in cell viability and colony formation, indicating that it confers a proliferative advantage and potentiates clonogenic capacity. Phosphokinase array and Western blot analyses suggested that the effects of the SPRY4 variant were mediated through the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway, which was further supported by a higher responsiveness of thyroid cancer cells with the SPRY4 variant to a MEK inhibitor. Conclusions: WES analysis in one family identified SPRY4 as a likely novel candidate susceptibility gene for FNMTC, allowing a better understanding of the cellular and molecular mechanisms underlying thyroid cancer development.

Epigenetic inheritance of polycystic ovary syndrome - challenges and opportunities for treatment

Polycystic ovary syndrome (PCOS) is the main cause of female infertility worldwide and is associated with a substantially increased lifetime risk of comorbidities, including type 2 diabetes mellitus, psychiatric disorders and gynaecological cancers. Despite its high prevalence (~15%) and substantial economic burden, the aetiology of PCOS remains elusive. The genetic loci linked to PCOS so far account for only ~10% of its heritability, which is estimated at 70%. However, growing evidence suggests that altered epigenetic and developmental programming resulting from hormonal dysregulation of the maternal uterine environment contributes to the pathogenesis of PCOS. Male as well as female relatives of women with PCOS are also at an increased risk of developing PCOS-associated reproductive and metabolic disorders. Although PCOS phenotypes are highly heterogenous, hyperandrogenism is thought to be the principal driver of this condition. Current treatments for PCOS are suboptimal as they can only alleviate some of the symptoms; preventative and targeted treatments are sorely needed. This Review presents an overview of the current understanding of the aetiology of PCOS and focuses on the developmental origin and epigenetic inheritance of this syndrome.

One Disease with two Faces: Semidominant Inheritance of a Novel HTRA1 Mutation in a Consanguineous Family

OBJECTIVES

To identify the underlying genetic defect for a consanguineous family with an unusually high number of members affected by cerebral small vessel disease.

MATERIALS AND METHODS

A total of 6 individuals, of whom 3 are severely affected, from the family were clinically and radiologically evaluated. SNP genotyping was performed in multiple members to demonstrate genome-wide runs-of-homozygosity. Coding variants in the most likely candidate gene, HTRA1 were explored by Sanger sequencing. Published HTRA1-related phenotypes were extensively reviewed to explore the effect of number of affected alleles on phenotypic expression.

RESULTS

Genome-wide homozygosity mapping identified a 3.2 Mbp stretch on chromosome 10q26.3 where HTRA1 gene is located. HTRA1 sequencing revealed an evolutionarily conserved novel homozygous c.824C>T (p.Pro275Leu) mutation, affecting the serine protease domain of HtrA1. Early-onset of cognitive and motor deterioration in homozygotes are in consensus with CARASIL. However, there was a clear phenotypic variability between homozygotes which includes alopecia, a suggested hallmark of CARASIL. All heterozygotes, presenting as CADASIL type 2, had spinal disk degeneration and several neuroimaging findings, including leukoencephalopathy and microhemorrhage despite a lack of severe clinical presentation.

CONCLUSION

Here, we clearly demonstrate that CARASIL and CADASIL type 2 are two clinical consequences of the same disorder with different severities thorough the evaluation of the largest collection of homozygotes and heterozygotes segregating in a family. Considering the semi-dominant inheritance of HTRA1-related phenotypes, genetic testing and clinical follow-up must be offered for all members of a family with HTRA1 mutations regardless of symptoms.

Inherited Variants in SCARB1 Cause Severe Early-Onset Coronary Artery Disease

[Figure: see text].

Digging the channels of inheritance: On how to distinguish between cultural and biological inheritance

Theories of cultural evolution rest on the assumption that cultural inheritance is distinct from biological inheritance. Cultural and biological inheritance are two separate so-called channels of inheritance, two sub-systems of the sum total of developmental resources travelling in distinct ways between individual agents. This paper asks: what justifies this assumption? In reply, a philosophical account is offered that points at three related but distinct criteria that (taken together) make the distinction between cultural and biological inheritance not only precise but also justify it as real, i.e. as ontologically adequate. These three criteria are (i) the autonomy of cultural change, (ii) the near-decomposability of culture and (iii) differences in temporal order between cultural and biological inheritance. This article is part of the theme issue 'Foundations of cultural evolution'.

Chicken embryo as a model in epigenetic research

Epigenetics is defined as the study of changes in gene function that are mitotically or meiotically heritable and do not lead to a change in DNA sequence. Epigenetic modifications are important mechanisms that fine tune the expression of genes in response to extracellular signals and environmental changes. In vertebrates, crucial epigenetic reprogramming events occur during early embryogenesis and germ cell development. Chicken embryo, which develops external to the mother's body, can be easily manipulated in vivo and in vitro, and hence, it is an excellent model for performing epigenetic studies. Environmental factors such as temperature can affect the development of an embryo into the phenotype of an adult. A better understanding of the environmental impact on embryo development can be achieved by analyzing the direct effects of epigenetic modifications as well as their molecular background and their intergenerational and transgenerational inheritance. In this overview, the current possibility of epigenetic changes during chicken embryonic development and their effects on long-term postembryonic development are discussed.

Disparity between central and peripheral refraction inheritance in twins

The last decades have witnessed a sudden increase in myopia incidence among youngsters that have been related to modern lifestyle along with the use of emerging technologies affecting visual exposure. Increasing exposures to known risk factors for myopia, such as time spent indoors, close-distance work, or low-light conditions are thought to be responsible for this public health issue. In most cases, development of myopia is secondary to a vitreous chamber enlargement, although the related mechanisms and the potential interaction between central and peripheral retinal area remain unclear. For a better understanding, we performed a classical twin study where objective refractive error along 70° of horizontal retinal arc was measured in 100 twin pairs of university students, 78% of which showed manifest myopia. We found the variance of shared environmental origin (range 0.34 to 0.67) explained most of the objective refractive error variance within central 42° of the retina (22° temporal to 19° nasal), whereas additive genetic variance (range 0.34 to 0.76) was predominant in the peripheral retinal areas measured. In this sample of millennial university students, with a large prevalence of myopia, environmental exposures were mostly responsible for inter-individual variation in the retinal horizontal area surrounding the macula, while their relative weight on phenotypic variance was gradually descending, and replaced by the variance of genetic origin, towards the retinal periphery.

Malignant salivary gland tumours in families with breast cancer susceptibility

Salivary gland cancers (SGCs) are rare malignancies with highly heterogeneous histological features. Patients affected with SGCs are at increased risk of secondary malignancies, including breast cancer (BC). Previous studies enlightened a possible link between SGCs and hereditary predisposition to BC. Here, we searched for SGC-affected patients in 1796 high-risk BC families recruited at the Genetic Unit of the Istituto Nazionale dei Tumori of Milan, 516 of which carried pathogenic variants in BRCA1 and/or BRCA2, the main genetic risk factors for BC. We detected five families with an individual affected with SGC, including two male patients, one carrying a constitutional mutation in BRCA1 and the other in BRCA2. Loss of heterozygosity of BRCA wild-type alleles was assessed in the patients' tumour DNA. We conclude that our observations support the hypothesis that genetic factors associated with BC susceptibility might play a role also in at least a subset of SGCs.