DOCSLIB.ORG

Moral Problems in Behavioural Genetics – Should We Find 'Genes For'

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Moral Problems in Behavioural Genetics – Should We Find 'Genes For' MORAL PROBLEMS IN BEHAVIOURAL GENETICS – SHOULD WE FIND ‘GENES FOR’ INTELLIGENCE? By Ainsley Janelle Newson, B.Sc(Hons) Submitted in total fulfilment of the requirements of the degree of Doctor of Philosophy Centre for the Study of Health and Society The University of Melbourne June 2002 ABSTRACT In this thesis, I provide an analysis of the moral and practical problems associated with undertaking behavioural genetic research. Of the many projects in behavioural genetics, each with distinct issues, I have chosen to focus upon genetic research into intelligence. The main question framing this thesis is whether there can be any ethical applications of this research. I argue that there can. The rationale of the thesis is therefore to describe the circumstances in which such applications might be acceptable. Genetic research into influences on intelligence is both topical and controversial. To award this issue a comprehensive analysis, it has been necessary for me to address several different issues. In order to ensure that an ethical analysis of this research is provided in an appropriate context, I begin by examining several important issues. The first is that the very definition of intelligence and the grounds for its genetic research are contentious. I review this debate in the first chapter. Additionally, there is concern that permitting genetic research into intelligence constitutes an undue promotion of the significance of genetic factors. I therefore also analyse the limitations in interpreting this information. In the second chapter, I establish the ethical context in which debates over genetic research into intelligence have been undertaken. That is, I review and provide some initial analysis of arguments against the research. I utilise this analysis to identify important issues which I discuss in detail in later chapters. One such issue is to what extent intelligence might contribute to the well-being of those who have it. To date, very little analysis has been performed (from a philosophical perspective) as to the value of any behavioural trait. I devote a chapter to discussing the value of intelligence, incorporating an analysis of both theoretical and empirical literature. ii The majority of the thesis is dedicated to addressing the moral issues around two important clinical applications that might result from genetic research into intelligence. The first is whether it would be appropriate to ever develop genetic tests for intelligence (and to whom they should be administered). The second is whether it would ever be appropriate to augment intelligence. In both cases, I offer a defence of such applications, subject to several important constraints. These constraints involve recognising the limitations of the predictive properties of behavioural genetic information, respecting the future interests of children in choosing their own life plan, ensuring that the interests of groups are protected and ensuring that choosing to utilise the various (potential) enhancement technologies does not harm parental interests. This thesis marks one of the first attempts to fill a conspicuous gap in bioethics literature. My analysis is the first to assess ethical issues in behavioural genetics by utilising a framework where both ethical and empirical approaches are included. This represents progress towards practically-based, ethically-derived solutions for emerging problems in genetic research. iii STATEMENT OF ORIGINALITY This is to certify that (i) The thesis comprises only my original work towards the PhD except where indicated in the Preface; (ii) Due acknowledgement has been made in the text to all other material used; (iii) The thesis is less than 100,000 words in length, exclusive of tables, maps, bibliographies and appendices. Signed: Ainsley Janelle Newson iv PREFACE The work presented in this thesis represents my own research. No work has been submitted for any other qualification, or has been carried out prior to my PhD candidature. Advice has been sought from experts to assist with various thesis chapters and I have listed these experts in the Acknowledgments. Where their contribution has been utilised in a chapter, it is recognized by a footnote. Two sections of this thesis have been published: Sections of Chapter Seven will appear in: Newson, A.J. ‘Is there a cost associated with Genetic Enhancements?’ in Almond, B. and Parker, M (Eds.) Ethical Issues and the New Genetics: Are Genes Us? Aldershot, Ashgate (Forthcoming, 2002). Sections of Chapters One, Two, Four and Five appeared in: Newson A. & Williamson R. (1999). ‘Should we undertake genetic research on intelligence?’ Bioethics. 13(3-4):327-342. v ACKNOWLEDGMENTS Due to the multidisciplinary influences on this thesis, there are many people who have provided academic and personal support throughout its preparation. I must first recognise the enormous contribution, support and patience of Professor Julian Savulescu. He has provided me with expert supervision, advice on resources, commentary on drafts and direction of the project as it developed. When I felt that I had exhausted all possibilities on a particular issue, Julian was instrumental in assisting me to find my way. Professor Bob Williamson has provided me with many opportunities to access experts in the field and has provided me with much-needed advice about doctoral- student life in general. Bob also provided excellent feedback on writing technique and clarity, in addition to substantive comments on thesis content. Dr David McCarthy supervised my project in its second year. Through attendance at his philosophy classes and by reading and discussing his work, I gained an enormous amount of knowledge about ethical theory. David also provided direction to several thesis chapters, particularly Chapters Four and Seven. Staff members at The Centre for the Study of Health and Society at The University of Melbourne have also been a source of support, stimulation and advice. Dr Lynn Gillam in particular has provided outstanding independent guidance on the scope and direction of my thesis. I would like to recognise the support of fellow students, particularly Dr Edwina Vance and Jan Hodgson for their friendship and research support. The multidisciplinary nature of this work necessitated seeking external expertise on numerous occasions. I thank the following people for their generous provision of time and resources: • Professor Tony Hope, Dr Michael Parker, Dr John McMillan and Don Hill from Ethox, The Centre for Ethics and Communication in health at The University of Oxford. • Professor Con Stough from the Brain Sciences Institute at Swinburne University for his assistance in the preparation of Chapters One, Three and Five. vi • Professor Robert Plomin from the Institute of Psychiatry at King’s College, London for his ongoing commitment to discussion about the implications of his work, the availability of his colleagues (particularly Dr Thalia Eley and Dr Brien Riley) and his assistance throughout the drafting process. • Professor Michael O’Boyle and Dr Mary Ainley from the Morgan Centre for the Study of the Development of High Intellectual Potential at the Department of Psychology, University of Melbourne for their assistance with the preparation of Chapter Three. • Professor John Geake, Professor of Education and Postgraduate Tutor at the Westminster Institute of Education at Oxford Brookes University, for his comments upon Chapter Three. • Dr Tom Shakespeare from the Centre for Life, Newcastle University (United Kingdom) and Ms Yvonne Melia, Nuffield Council on Bioethics, for valuable research assistance. • Associate Professor Vicki Anderson from the Department of Psychology at The University of Melbourne, for her assistance with Chapter Four. I would also like to thank the staff and students of the Ethics Unit at The Murdoch Childrens Research Institute for their support and advice, including Dr Merle Spriggs, Melanie Hemsley and Rony Duncan. Cate Azzopardi, Belinda Griffiths, Wonitta Hodge and Danielle Irvine have provided enormous personal encouragement. The Oxford ‘crew’ of Dr Emily Howman, Dr Alyssa Barry and those at # 43 were also enormously supportive. My partner Evan Hollonds has been an unwavering support throughout my candidature. His patience, support, IT assistance and proofreading skills were much appreciated. I would also like to warmly thank Don, Lyverne and Kirrily Newson, Bruce and Rhonda Hollonds and James and Anne Bukovsan for their support. Finally, I would like to thank my cat Alby for keeping me company during the long days of writing and for occasionally helping me with word processing. vii TABLE OF CONTENTS ABSTRACT...................................................................................................ii STATEMENT OF ORIGINALITY ...........................................................iv ACKNOWLEDGEMENTS.........................................................................vi TABLE OF CONTENTS..........................................................................viii INDEX OF TABLES.................................................................................xiii THESIS OVERVIEW................................................................................. xv SECTION I: Research Background and Overview of Ethical Issues CHAPTER ONE: What is Intelligence? What Might Genetic Research Achieve? 1.1 INTRODUCTION .....................................................................................................2 1.2 WHAT IS INTELLIGENCE? .....................................................................................3
Load more

Recommended publications
  • Cognitive Ability and Education: How Behavioural Genetic Research Has Advanced Our Knowledge and Understanding of Their Association
    Cognitive ability and education: how behavioural genetic research has advanced our knowledge and understanding of their association Margherita Malanchini1,2,3, Kaili Rimfeld2, Andrea G. Allegrini2, Stuart J. Ritchie2, & Robert Plomin2 1 Department of Biological and Experimental Psychology, Queen Mary University of London, United Kingdom. 2 Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, United Kingdom. 3 Population Research Center, The University of Texas at Austin, United States. Correspondence: Margherita Malanchini, Department of Biological and Experimental Psychology, Queen Mary University of London, Office 2.02, G.E. Fogg Building, Mile End Road, London E1 4NS. E-mail: [email protected] Abstract Cognitive ability and educational success predict positive outcomes across the lifespan, from higher earnings to better health and longevity. The shared positive outcomes associated with cognitive ability and education are emblematic of the strong interconnections between them. Part of the observed associations between cognitive ability and education, as well as their links with wealth, morbidity and mortality, are rooted in genetic variation. The current review evaluates the contribution of decades of behavioural genetic research to our knowledge and understanding of the biological and environmental basis of the association between cognitive ability and education. The evidence reviewed points to a strong genetic basis in their association, observed from middle childhood to old age, which is amplified by environmental experiences. In addition, the strong stability and heritability of educational success are not driven entirely by cognitive ability. This highlights the contribution of other educationally relevant noncognitive characteristics. Considering both cognitive and noncognitive skills as well as their biological and environmental underpinnings will be fundamental in moving towards a comprehensive, evidence-based model of education.
    [Show full text]
  • To What Extent Does the Heritability Of
    1 Bonamy R. Oliver & Alison Pike University of Sussex 'To what extent does the heritability of known features of development such as intelligence limit the potential of policy that attempts to lessen intergenerational inequalities such as early intervention, social mobility, child poverty or the social class attainment gap'. In the current report, we argue that the extent to which aspects of human development are heritable has little impact on the importance of policy that aims to ameliorate the adverse effects of environmental or intergenerational inequalities. We first address common misconceptions about heritability and behavioural genetics that can lead to inappropriate assertions about research findings and their implications for policy. We then move to demonstrate our vision of what behavioural genetics can offer early intervention science and attempts to lessen intergenerational inequality. What is behavioural genetics? Behavioural genetic research uses a variety of quasi-experimental designs to understand the role of genetic and environmental influence on variation in psychological traits such as general intelligence (e.g., Deary, Johnson, & Houlihan, 2009), disruptive behaviour (e.g., Rhee, & Waldman, 2002), and well-being (e.g., Bartels, 2015). The extent to which variance in a given trait is explained by genetic variance is termed ‘heritability’, and is explained further below. Shared environmental influences refer to experiences that contribute to sibling similarity, while non- shared environmental influences refer to differences in experience that contribute to differences between siblings in a family. The most common of these research designs are twin and adoption 2 studies. The twin design compares monozygotic (MZ: ‘identical’) and dizygotic (DZ: fraternal, ‘not identical’) twin similarity for specific psychological traits.
    [Show full text]
  • Holmes CV Current.Pdf
    Biosketch NAME POSITION TITLE Andrew Holmes, Ph.D. Acting Chief, Section on Behavioral Science and Genetics, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health EDUCATION/TRAINING DEGREE INSTITUTION AND LOCATION (if applicable) YEAR(s) FIELD OF STUDY Department of Psychology, University of B.A. (Hons) 1992-1995 Psychology Newcastle upon Tyne, UK Department of Psychology, University of Ph.D. 1995-1999 Behavioral Pharmacology Leeds, UK (Mentor, RJ Rodgers) National Institute of Mental Health, Visiting Fellow 1999-2003 Behavioral Neuroscience National Institutes of Health, USA (Mentor, JN Crawley) Awards 2008: United States - Israel Binational Science Foundation Four-Year Grant Award 2008: Alcoholism and Stress: A Framework for Future Treatment Strategies, Young Investigator Award 2007: Senior Preclinical Wyeth Psychopharmacology Award, British Association of Psychopharmacology 2006: Young Scientist Award, International Behavioural and Neural Genetics Society 2005: National Alliance for Research on Schizophrenia and Depression Young Investigator Award 2004: NIH Pre-IRTA Committee Awards for outstanding contributions to the post-baccalaureate training and education 2003: Anxiety Disorders Association of America/American College of Neuropsychopharmacology Career Development Travel Award 2003: Howard Hughes Medical Institute Student Mentor Award 2002: NIH Fellows Award for Research Excellence 2002: New York Academy of Sciences Travel Award 2001: American College of Neuropsychopharmacology/Bristol-Myers
    [Show full text]
  • Holding Back the Genes: Limitations of Research Into Canine Behavioural
    van Rooy et al. Canine Genetics and Epidemiology 2014, 1:7 http://www.cgejournal.org/content/1/1/7 REVIEW Open Access Holding back the genes: limitations of research into canine behavioural genetics Diane van Rooy*, Elizabeth R Arnott, Jonathan B Early, Paul McGreevy and Claire M Wade Abstract Canine behaviours that are both desirable and undesirable to owners have a demonstrable genetic component. Some behaviours are breed-specific, such as the livestock guarding by maremmas and flank sucking seen in Dobermanns. While the identification of genes responsible for common canine diseases is rapidly advancing, those genes underlying behaviours remain elusive. The challenges of accurately defining and measuring behavioural phenotypes remain an obstacle, and the use of variable phenotyping methods has prevented meta-analysis of behavioural studies. International standardised testing protocols and terminology in canine behavioural evaluations should facilitate selection against behavioural disorders in the modern dog and optimise breeding success and performance in working dogs. This review examines the common hurdles faced by researchers of behavioural genetics and the current state of knowledge. Keywords: Behaviour, Dog, Genetics, Heritability Lay summary against behavioural disorders in the dog, and optimise All canine behaviour, whether desirable or undesirable breeding success and performance in working dogs. to owners, has a genetic component. Studies of “showing This review examines the common hurdles faced by eye” and “bark” which compared the behaviour of off- researchers of behavioural genetics and the current state spring with parents concluded that behaviour does not of knowledge. follow simple Mendelian inheritance. Some behaviours are breed-specific, such as “livestock guarding” by mar- Introduction emmas and “flank sucking” seen in Dobermanns.
    [Show full text]
  • Genetics and Human Behaviour
    Cover final A/W13657 19/9/02 11:52 am Page 1 Genetics and human behaviour : Genetic screening: ethical issues Published December 1993 the ethical context Human tissue: ethical and legal issues Published April 1995 Animal-to-human transplants: the ethics of xenotransplantation Published March 1996 Mental disorders and genetics: the ethical context Published September 1998 Genetically modified crops: the ethical and social issues Published May 1999 The ethics of clinical research in developing countries: a discussion paper Published October 1999 Stem cell therapy: the ethical issues – a discussion paper Published April 2000 The ethics of research related to healthcare in developing countries Published April 2002 Council on Bioethics Nuffield The ethics of patenting DNA: a discussion paper Published July 2002 Genetics and human behaviour the ethical context Published by Nuffield Council on Bioethics 28 Bedford Square London WC1B 3JS Telephone: 020 7681 9619 Fax: 020 7637 1712 Internet: www.nuffieldbioethics.org Cover final A/W13657 19/9/02 11:52 am Page 2 Published by Nuffield Council on Bioethics 28 Bedford Square London WC1B 3JS Telephone: 020 7681 9619 Fax: 020 7637 1712 Email: [email protected] Website: http://www.nuffieldbioethics.org ISBN 1 904384 03 X October 2002 Price £3.00 inc p + p (both national and international) Please send cheque in sterling with order payable to Nuffield Foundation © Nuffield Council on Bioethics 2002 All rights reserved. Apart from fair dealing for the purpose of private study, research, criticism or review, no part of the publication may be produced, stored in a retrieval system or transmitted in any form, or by any means, without prior permission of the copyright owners.
    [Show full text]
  • Open Universiteit Research Portal
    Adaptive and Genomic Explanations of Human Behaviour: Citation for published version (APA): Barendregt, M., & van Hezewijk, R. W. J. V. (2005). Adaptive and Genomic Explanations of Human Behaviour: Might Evolutionary Psychology Contribute to Behavioural Genomics? Biology & Philosophy, 20, 57-78. https://doi.org/10.1007/s10539-005-0388-2 DOI: 10.1007/s10539-005-0388-2 Document status and date: Published: 01/01/2005 Document Version: Peer reviewed version Document license: CC BY-NC-ND Please check the document version of this publication: • A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal.
    [Show full text]
  • The Nature and Significance of Behavioural Genetic Information
    Postprint This is a pre-copyedited, author-produced PDF of an article accepted for publication in Theoretical Medicine and Bioethics following peer review. The definitive publisher-authenticated version [Newson, A.J. (2004) “The nature and significance of behavioural genetic information.” Theoretical Medicine and Bioethics, 25: 89–111.] is available online at http://link.springer.com/article/10.1023/B:META.0000033764.50604.85 The nature and significance of behavioural genetic information Ainsley Newson BSc (Hons) PhD, 2004 Abstract In light of the human genome project, establishing the genetic aetiology of complex human diseases has become a research priority within Western medicine. However, in addition to the identification of disease genes, numerous research projects are also being undertaken to identify genes contributing to the development of human behavioural characteristics, such as cognitive ability and criminal tendency. The permissibility of this research is obviously controversial: will society benefit from this research, or will it adversely affect our conceptions of ourselves and each other? When assessing the permissibility of this research, it is important to consider the nature and deterministic significance of behavioural genetic information. Whilst to date there has been much discussion and debate about the properties of genetic information per se and genetic determinism, this has not been applied to behavioural genetic research and its ethical implications. Therefore, this paper elucidates how behavioural genetic information can be distinguished from different from other types of genetic and non-genetic information and also synthesises the determinative significance of genetic factors for the development of human behavioural traits. Undertaking this analysis enables the ethical issues raised by this research to be debated in an appropriate context and indicates that separate policy considerations are warranted.
    [Show full text]
  • Genetics and Human Behaviour: the Ethical Context a Guide to the Report
    Genetics and human behaviour: the ethical context a guide to the Report Introduction Do we inherit our behaviour? Or The Nuffield Council on Bioethics does it depend on our upbringing? has published a Report, Genetics There is little doubt that genes and human behaviour: the ethical do have some influence on our context, which examines the ethical, personality. But how much? legal and social issues that Research to find out how our genes behavioural genetics raises. This influence our behaviour is complex summary sets out some of the and controversial. There are concerns arguments and recommendations both about the science itself and the which are discussed in more detail potential applications. in the Report. [Notes in square brackets throughout refer to chapters and paragraphs in the Report]. What is behavioural genetics? Research in the field of behavioural genetics aims to find out how genes influence our behaviour. Researchers are trying to identify particular genes, or groups of genes, that are associated with behavioural traits, and investigating the role of environmental factors. Scientific background The Report considers behavioural traits such What is normal? as intelligence, personality (including anxiety, novelty-seeking and shyness), antisocial behaviour We use a statistical definition of ‘normal’ to refer (including aggression and violent behaviour) and to the range of variation, usually about 95% of sexual orientation. The focus is on behaviour the population, which does not contain anyone within the normal range of variation, rather than with clinical disorders or diseases. This use of diseases or disorders. ‘normal’ does not imply any value judgement about different forms of behaviour.
    [Show full text]
  • Behavioral Genetics and Neurogenetics» for 37.04.01 «Cognitive Sciences and Technologies: from Neuron to Cognition», Master of Science
    National Research University Higher School of Economics Syllabus for the course «Behavioral genetics and neurogenetics» for 37.04.01 «Cognitive sciences and technologies: from neuron to cognition», Master of Science Government of Russian Federation Federal State Autonomous Educational Institution of High Education «National Research University Higher School of Economics» Faculty of Social science Department of Psychology Syllabus for the course «Behavioral genetics and neurogenetics» 37.04.01 «Cognitive sciences and technologies: from neuron to cognition», Master of Science Authors: Yulia Kovas, Ph.D in behavioral genetics, professor, Goldsmiths University of London - [email protected] And Olga V. Sysoeva, PhD of psychological sciences, Senior researcher in MEG Center, MGPPU, [email protected] Approved by Academic Council: «_29_»__августа___ 2017 г., № _51___________ Academic supervisor of the «Cognitive sciences and technologies: from neuron to cognition» Dr. Anna Shestakova __________________________ Moscow, 2017 This syllabus may not be used by other departments of the University and by any other institutions without permission of the Author. National Research University Higher School of Economics Syllabus for the course «Behavioral genetics and neurogenetics» for 37.04.01 «Cognitive sciences and technologies: from neuron to cognition», Master of Science Summary “Behavioral genetics” will promote an understanding of the current state of affairs with regards to behavioural genetics. Basic principles as well as recent developments will be explored in relation to a broad range of phenotypes. Historical and ethical issues will be discussed. The structure and function of DNA will be studied in the context of investigations into individual variation in psychological traits. Students will be introduced to behavioural genomic analysis, such as investigating gene-environment interaction, testing educational interventions, and testing the generalist genes hypotheses - using information on measured genes and measured environments.
    [Show full text]
  • Use of Q-Methodology to Identify Clinical Psychologists' Attitudes
    1 Use of Q-methodology to identify clinical psychologists’ attitudes towards genetic research affecting people with intellectual and developmental disabilities A thesis submitted to the University of Manchester for the degree of Doctorate of Clinical Psychology in the Faculty of Medical and Human Sciences 2013 CATHERINE ANN VAHEY School of Psychological Sciences, Division of Clinical Psychology 1 The New Genetics and Clinical Psychology List of Contents List of Appendices ....................................................................................................... 7 List of Tables................................................................................................................ 8 List of Figures .............................................................................................................. 9 Abstract ...................................................................................................................... 10 Declaration ................................................................................................................. 11 Copyright Statement .................................................................................................. 12 Acknowledgements .................................................................................................... 14 Chapter 1: Introduction .............................................................................................. 15 1.1 Study Overview ...................................................................................................
    [Show full text]
  • The Evolutionary Genetics of Personalityy
    European Journal of Personality Eur. J. Pers. 21: 549–587 (2007) Published online 27 April 2007 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/per.629 The Evolutionary Genetics of Personalityy LARS PENKE1,2*, JAAP J. A. DENISSEN3 and GEOFFREY F. MILLER4 1Humboldt University, Berlin, Germany 2International Max Planck Research School LIFE, Berlin, Germany 3Utrecht University, Utrecht, The Netherlands 4University of New Mexico, Albuquerque, NM, USA Abstract Genetic influences on personality differences are ubiquitous, but their nature is not well understood. A theoretical framework might help, and can be provided by evolutionary genetics. We assess three evolutionary genetic mechanisms that could explain genetic variance in personality differences: selective neutrality, mutation-selection balance, and balancing selection. Based on evolutionary genetic theory and empirical results from behaviour genetics and personality psychology, we conclude that selective neutrality is largely irrelevant, that mutation-selection balance seems best at explaining genetic variance in intelligence, and that balancing selection by environmental heterogeneity seems best at explaining genetic variance in personality traits. We propose a general model of heritable personality differences that conceptualises intelligence as fitness components and personality traits as individual reaction norms of genotypes across environments, with different fitness consequences in different environmental niches. We also discuss the place of mental health in the model. This evolutionary genetic framework highlights the role of gene-environment interactions in the study of personality, yields new insight into the person-situation-debate and the structure of personality, and has practical implications for both quantitative and molecular genetic studies of personality. Copyright # 2007 John Wiley & Sons, Ltd.
    [Show full text]
  • Behavior Genetics and Postgenomics
    BEHAVIORAL AND BRAIN SCIENCES (2012), Page 1 of 80 doi:10.1017/S0140525X11002226 Behavior genetics and postgenomics Q1 Evan Charney Department of Public Policy and Political Science, Duke Institute for Brain Sciences, Duke Institute for Genome Sciences and Policy, Duke University, Durham NC 90239 http://fds.duke.edu/db/Sanford/faculty/echar Abstract: The science of genetics is undergoing a paradigm shift. Recent discoveries, including the activity of retrotransposons, the extent of copy number variations, somatic and chromosomal mosaicism, and the nature of the epigenome as a regulator of DNA expressivity, are challenging a series of dogmas concerning the nature of the genome and the relationship between genotype and phenotype. According to three widely held dogmas, DNA is the unchanging template of heredity, is identical in all the cells and tissues of the body, and is the sole agent of inheritance. Rather than being an unchanging template, DNA appears subject to a good deal of environmentally induced change. Instead of identical DNA in all the cells of the body, somatic mosaicism appears to be the normal human condition. And DNA can no longer be considered the sole agent of inheritance. We now know that the epigenome, which regulates gene expressivity, can be inherited via the germline. These developments are particularly significant for behavior genetics for at least three reasons: First, epigenetic regulation, DNA variability, and somatic mosaicism appear to be particularly prevalent in the human brain and probably are involved in much of human behavior; second, they have important implications for the validity of heritability and gene association studies, the methodologies that largely define the discipline of behavior genetics; and third, they appear to play a critical role in development during the perinatal period and, in particular, in enabling phenotypic plasticity in offspring.
    [Show full text]