DOCSLIB.ORG

Integrating Inclusive Inheritance Into an Extended Theory of Evolution

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Integrating Inclusive Inheritance Into an Extended Theory of Evolution REVIEWS Beyond DNA: integrating inclusive inheritance into an extended theory of evolution Étienne Danchin*‡, Anne Charmantier§, Frances A. Champagne||, Alex Mesoudi¶, Benoit Pujol*‡ and Simon Blanchet*# Abstract | Many biologists are calling for an ‘extended evolutionary synthesis’ that would ‘modernize the modern synthesis’ of evolution. Biological information is typically considered as being transmitted across generations by the DNA sequence alone, but accumulating evidence indicates that both genetic and non-genetic inheritance, and the interactions between them, have important effects on evolutionary outcomes. We review the evidence for such effects of epigenetic, ecological and cultural inheritance and parental effects, and outline methods that quantify the relative contributions of genetic and non-genetic heritability to the transmission of phenotypic variation across generations. These issues have implications for diverse areas, from the question of missing heritability in human complex-trait genetics to the basis of major evolutionary transitions. Modern synthesis When Charles Darwin was born in 1809, the idea causes, one of which is that heritability estimates are 10 The merging of Darwinism with that species change over time — that is, evolve — had incorrect , or at least misinterpreted, mainly because genetics that occurred from already emerged1. However, it was only half a century non-genetic heritability is often confounded with the 1930s to the 1950s. later, when Darwin published On the Origin of Species2, purely genetic effects. There is increasing awareness that the theory of evolution profoundly transformed that non-genetic information can also be inherited our understanding of life. Darwin understood that across generations (reviewed in REFS 8,11–13). The natural selection can only affect traits in which there is concepts of ‘general heritability’ (REF. 5) or ‘inclusive variation that is transmitted from parents to offspring; heritability’ (REF. 9) were recently proposed to unify namely, traits that are heritable. Since then, the genetic and non-genetic heritability; the two terms merging of Darwinism with genetics into the modern are synonymous and aim at encompassing all synthesis has led to a semantic shift, resulting in the dimensions of inheritance. tendency to assume that only the DNA sequence is Non-genetic inherited information can arise inherited across generations3–8. However, evolution through several interacting mechanisms, including acts on any phenotypic differences that are stable epigenetics, parental effects and ecological and cultural across generations5,9. According to this view, phenotypic inheritance3,7–9,12,15. All forms of genetic and non-genetic variation should be partitioned into its transmitted inheritance contribute to phenotypic resemblance 7 *Centre National de la versus non-transmitted components rather than into between individuals . Distinguishing among these Recherce Scientifique (CNRS); its classical genetic and environmental components9. various components is crucial because their distinct Université Paul Sabatier; Today, the view that biological information is properties affect evolutionary dynamics in different École Nationale de Formation BOX 1 Agronomique (ENFA); transmitted from one generation to the next by the DNA ways. In particular, as described in , accounting 3,5–8 Laboratoire Évolution et sequence alone appears untenable . This became for the distinct properties of non-genetic inheritance Diversité Biologique (EDB), strikingly obvious when genome-wide association studies may resolve some major evolutionary enigmas. UMR5174, 118 route de (GWA studies) showed that most of the high heritabilities Here, we first briefly review the recent evidence for Narbonne, 31062 Toulouse for phenotypic traits, such as height or common human non-genetic inheritance. Understanding the different cedex 9, France. Correspondence to É.D. diseases, could not be explained by common genetic properties of the various modes of inheritance is 10 e‑mail: [email protected] variants (BOX 1). This lack of a link between variation necessary to fully grasp the impact of non-genetic doi:10.1038/nrg3028 in DNA sequence and heritability might have several inheritance on evolution. Second, we consider the NATURE REVIEWS | GENETICS VOLUME 12 | JULY 2011 | 475 © 2011 Macmillan Publishers Limited. All rights reserved REVIEWS Genome-wide association network of interactions occurring between these Transgenerational epigenetic inheritance can take two studies different forms of inheritance. Third, we introduce contrasting forms (FIG. 1). First, in germline epigenetic (GWA studies). These are the rationale of formally decomposing phenotypic inheritance, the epigenetic state of the DNA is present studies in which associations variation between transmitted versus non-transmitted in germline cells and is thus transmitted to the offspring between genetic variation and a phenotype or trait of interest components, while highlighting the variety and over many generations by transgenerational epigenetic are identified by genotyping importance of non-genetic components of inclusive inheritance (FIG. 1a). For example, prenatal exposure cases (for example, diseased heritability. Fourth, we review methods that can be to the pesticide vinclozolin induces changes in DNA individuals) and controls (for used to estimate the relative weight of each non- methylation in the first filial generation (F1) male example, healthy individuals) genetic component of inclusive heritability and their offspring that are observed to persist to the F generation for a set of genetic variants 4 22 that capture variation across interactions with genetic inheritance. Finally, we call for and beyond in male gametes . Conversely, in experience- the entire genome. Tests of an extended modern synthesis that would not reduce dependent epigenetic inheritance, an epigenetic state statistical association with a inheritance to genes and that would incorporate all affects parental behaviour in a way that generates the same phenotype are performed forms of inheritance9,12,13 to constitute a comprehensive epigenetic state in offspring. For example, in laboratory locally along the genome. evolutionary theory. rats there is transgenerational continuity in individual Heritability differences in postnatal maternal pup licking (FIG. 1b). The percentage of variation Epigenetic inheritance This inheritance depends on maternal licking-induced in a trait that is genetically Today, species evolution through neutral divergence or as epigenetic changes in offspring neural circuits, which transmitted to offspring. a response to natural selection is thought to act primarily alter adult maternal behaviour of offspring23. This effect 23 Inclusive heritability on phenotypic variation resulting from variation in the may persist over many generations . In this example, 16 The percentage of variation DNA sequence . However, phenotypic variation may parental effects and epigenetics interact in producing in a trait that is transmitted also result from changes in DNA expression17–19, which inheritance. However, if maternal behaviour is altered between generations, whatever is determined by various epigenetic mechanisms. For by changes in the quality of the environment (for the mechanism of transmission. Inclusive heritability should example, post-translational modifications of histone example, stress or social isolation), there may be an 24,25 be greater than or equal to proteins and methylation of cytosines in DNA can interruption of the transgenerational continuity . heritability. activate, reduce or completely silence gene expression This possibility to lose epigenetic marks and revert to without altering the DNA sequence18,19. Epigenetics the ancestral phenotype when environmental conditions Prions encompasses the study of these modifications change constitutes a major difference between genetic Prion-forming proteins exist in different stable conformational and other gene-regulatory mechanisms involving and epigenetic inheritance that has major implications 20 states. In addition to a ‘native’ small RNAs, which can regulate gene expression . for adaptation. non-prion conformation, In metacellular organisms, epigenetic modifications One process by which epigenetic marks are they occasionally fold into of gene expression levels can be inherited during both transmitted between generations is genomic imprinting, a prion conformation that replicates itself by templating mitosis (that is, during development) and through whereby certain genes are expressed in a parent-of- 18,21 the conformational conversion transgenerational epigenetic inheritance (across origin-specific manner . Imprinted genes are thus of other molecules of the generations18). Mitotic epigenetic inheritance results only expressed from the alleles that are inherited from same protein. from the transmission of epigenetic marks (for example, one parent, which nullifies the benefits of diploidy of involving the methylation pattern of some genes) from those genes21. Forms of genomic imprinting have been parent to descendant cells. It allows cell differentiation demonstrated in insects, mammals and flowering without changes in the DNA sequence18. By contrast, plants21,26. Another process of transgenerational transgenerational epigenetic inheritance leads to the epigenetic inheritance involves an intimate interaction inheritance of epigenetic marks across generations18. between transposable elements and DNA methylation,
Load more

Recommended publications
  • Cancer-Milestones December 2020
    www.nature.com/collections/cancer-milestones December 2020 Cancer Produced by: With support from: Nature Genetics and Nature Medicine Cancer MILESTONES S2 Foreword S3 Timeline S4 Routes to resistance S5 Tracking cancer in liquid biopsies S6 When cancer prevention went viral S7 A licence to kill S8 Sitting on the fence S9 Not a simple switch S10 Sequencing the secrets of the cancer genome S11 Unleashing the immune system against cancer S12 Engineering armed T cells for the fight S13 Oncohistones: epigenetic drivers of cancer S14 Tumour evolution: from linear paths to branched trees S15 Undruggable? Inconceivable S16 Good bacteria make for good cancer therapy S17 The AI revolution in cancer Credit: S.Fenwick/Springer Nature Limited CITING THE MILESTONES VISIT THE SUPPLEMENT ONLINE SUBSCRIPTIONS AND CUSTOMER SERVICES Nature Milestones in Cancer includes Milestone articles written The Nature Milestones in Cancer supplement can be found at Springer Nature, Subscriptions, by our editors and an online Collection of previously published www.nature.com/collections/cancer-milestones Cromwell Place, Hampshire International Business Park, material. To cite the full project, please use Nature Milestones: Lime Tree Way, Basingstoke, Cancer https://www.nature.com/collections/cancer-milestones CONTRIBUTING JOURNALS Hampshire RG24 8YJ, UK (2020). Should you wish to cite any of the individual Milestones, BMC Cancer, Nature, Nature Cancer, Nature Communications, Tel: +44 (0) 1256 329242 please list Author, A. Title. Nature Milestones: Cancer <Article URL> Nature Genetics, Nature Medicine, Nature Reviews Cancer, [email protected] (2020). For example, Milestone 1 is Valtierra, I. Routes to resistance. Nature Reviews Clinical Oncology, Nature Reviews Drug Discovery, Customer serviCes: www.nature.com/help Nature Milestones: Cancer https://www.nature.com/articles/ Nature Reviews Gastroenterology & Hepatology, d42859-020-00069-6 (2020).
    [Show full text]
  • Understanding Biological Design from Synthetic Circuits
    REVIEWS MODELLING Synthetic biology: understanding biological design from synthetic circuits Shankar Mukherji* and Alexander van Oudenaarden‡ Abstract | An important aim of synthetic biology is to uncover the design principles of natural biological systems through the rational design of gene and protein circuits. Here, we highlight how the process of engineering biological systems — from synthetic promoters to the control of cell–cell interactions — has contributed to our understanding of how endogenous systems are put together and function. Synthetic biological devices allow us to grasp intuitively the ranges of behaviour generated by simple biological circuits, such as linear cascades and interlocking feedback loops, as well as to exert control over natural processes, such as gene expression and population dynamics. 10–12 Modularity One of the most astounding findings of the Human potential clinical applications . In this Review, however, A property of a system such Genome Project was that our genome contains as many we focus on how synthetic circuits help us to under- that it can be broken down into genes as that of Drosophila melanogaster. This finding stand how natural biological systems are genetically discrete subparts that perform begged the question: how do you get one organism to assembled and how they operate in organisms from specific tasks independently of look like a fly and another like a human with the same microbes to mammalian cells. In this light, synthetic the other subparts. number of genes? One possibility is that the rich rep- circuits have been crucial as simplified test beds in Bioremediation ertoire of non-protein-coding sequences found in the which to refine our ideas of how similarly structured The treatment of pollution with genomes of complex organisms adds many new parts natural networks function, and they have served as microorganisms.
    [Show full text]
  • Special Issues on Advances in Quantitative Genetics: Introduction
    Heredity (2014) 112, 1–3 & 2014 Macmillan Publishers Limited All rights reserved 0018-067X/14 www.nature.com/hdy EDITORIAL Special issues on advances in quantitative genetics: introduction Heredity (2014) 112, 1–3; doi:10.1038/hdy.2013.115 Fisher’s (1918) classic paper on the inheritance of complex traits not While much of the focus was on standard biometrical applications only founded the field of quantitative genetics, but also coined the (for example, variance components), hints of things to come were term variance and introduced the powerful statistical method of foreshadowed by papers on the relevance of molecular biology to analysis of variance. This was a watershed paper, reconciling the breeding and applications of mixed models (models including both Mendelian’s discrete and saltatorial view of trait evolution with the fixed and random effects, for example, BLUP and REML). Much of gradual and continuous view of Darwin’s followers, the biometricians the emphasis was on breeding or laboratory populations. A decade (Provine, 1971). This fusion of Mendelian genetics with Darwinian later, the second ICQG held at Raleigh, North Carolina in 1987 natural selection was the start of the modern evolutionary synthesis. (Weir et al., 1988), reflected explosive growth in new tools (low- Fisher’s paper also marked a critical point in modern statistics, and density molecular markers for early quantitative trait locus (QTL) this synergism between the development of new statistical methods mapping), a continued expansion of the importance of mixed-model and the ever-increasing complexity of genetic/genomic data sets methodology for complex estimation issues, and a growing fusion of continues to this day.
    [Show full text]
  • New Strategies and Tools in Quantitative Genetics: How to Go from the Phenotype to the Genotype
    PP68CH16-Loudet ARI 6 April 2017 9:43 ANNUAL REVIEWS Further Click here to view this article's online features: • Download figures as PPT slides • Navigate linked references • Download citations New Strategies and Tools in • Explore related articles • Search keywords Quantitative Genetics: How to Go from the Phenotype to the Genotype Christos Bazakos, Mathieu Hanemian, Charlotte Trontin, JoseM.Jim´ enez-G´ omez,´ and Olivier Loudet Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Universite´ Paris-Saclay, 78026 Versailles Cedex, France; email: [email protected] Annu. Rev. Plant Biol. 2017. 68:435–55 Keywords First published online as a Review in Advance on genetic architecture, QTL, RIL, GWAS, phenotype February 6, 2017 The Annual Review of Plant Biology is online at Abstract plant.annualreviews.org Quantitative genetics has a long history in plants: It has been used to study https://doi.org/10.1146/annurev-arplant-042916- specific biological processes, identify the factors important for trait evolu- 040820 Annu. Rev. Plant Biol. 2017.68:435-455. Downloaded from www.annualreviews.org tion, and breed new crop varieties. These classical approaches to quantitative Copyright c 2017 by Annual Reviews. trait locus mapping have naturally improved with technology. In this review, All rights reserved we show how quantitative genetics has evolved recently in plants and how new developments in phenotyping, population generation, sequencing, gene Access provided by INRA Institut National de la Recherche Agronomique on 05/05/17. For personal use only. manipulation, and statistics are rejuvenating both the classical linkage map- ping approaches (for example, through nested association mapping) as well as the more recently developed genome-wide association studies.
    [Show full text]
  • Phenotypic and Molecular Analysis of Mes-3, a Maternal-Effect Gene Required for Proliferation and Viability of the Germ Line in C
    Copyright 0 1995 by the Genetics Society of America Phenotypic and Molecular Analysis of mes-3, a Maternal-Effect Gene Required for Proliferation and Viability of the Germ Line in C. eleguns Janet E. Paulsen,' Elizabeth E. Capowski2 and Susan Strome Department of Biology, Indiana University, Bloomington, Indiana 47405 Manuscript received July 24, 1995 Accepted for publication September 14, 1995 ABSTRACT mes-3 is one of four maternaleffect sterile genes that encode maternal components required for normal postembryonic development of the germ line in Caenorhabditis elegans. mes-3 mutant mothers produce sterile progeny, which contain few germ cells andno gametes. This terminal phenotype reflects two problems: reduced proliferation of the germ line and germ cell death. Both the appearanceof the dying germ cells and the results of genetic tests indicate that germ cells in mes-3 animals undergo a necrotic-like death, not programmedcell death. The few germ cells that appear healthyin mes-3 worms do not differentiateinto gametes, even after eliminationof the signaling pathway that normally maintains the undifferentiated population of germ cells. Thus, mes-3 encodes a maternally supplied product that is required both for proliferation of the germ line and for maintenance of viable germ cells that are competent to differentiate into gametes. Cloning and molecular characterizationof mes-3 revealed that it is the upstream gene in an operon. The genes in the operon display parallel expression patterns; transcripts are present throughout development and are not restricted to germ-line tissue. Both mes-3 and the downstream gene in the operon encode novel proteins. HE germ line enables metazoan organisms to pro- germ cell, P4, at the 16-24cell stage.
    [Show full text]
  • Michael Lynch
    1 Michael Lynch Center for Mechanisms of Evolution, Biodesign Institute Arizona State University Tempe, AZ 85287 Phone: 480-965-0868 Email: [email protected] Birth: 6 December 1951, Auburn, New York Undergraduate education: St. Bonaventure University, Biology - B.S., 1973. Graduate education: University of Minnesota, Ecology and Behavioral Biology - Ph.D., 1977 (advisor: J. Shapiro). Areas of Interest and Research: The integration of molecular and cellular biology, genetics, and evolution; population and quantitative genetics; molecular, genomic, and phenotypic evolution. Select Professional Activities and Service: Director, Biodesign Center for Mechanisms of Evolution, Arizona State University, 2017 – present. Professor, School of Life Sciences, Arizona State University, 2017 – present. Class of 1954 Professor, 2011 – 2017. Distinguished Professor, Indiana University, 2005 – 2017. Professor; Biology, Indiana University, 2001 – 2004. Adjunct Professor, Computer Science, Indiana University, 2014 – 2017. Adjunct Professor, Physics, Indiana University, 2015 – 2017. Professor; Biology, University of Oregon, 1989 – 2001. Director, Ecology and Evolution Program, Univ. of Oregon, 1989 – 1993, 1996 – 2000. Asst., Assoc., Full Professor; Ecology, Ethology, and Evolution; University of Illinois, 1977 – 1989. Co-director, NSF IGERT Training Grant in Evolution, Development, and Genomics, 1999 – 2004. Director, NSF Genetic Mechanisms of Evolution Training Grant, 1990 – 2000. President, Genetics Society of America, 2013. President, Society for Molecular Biology and Evolution, 2009. President, American Genetic Association, 2007. President, Society for the Study of Evolution, 2000. Chair-elect, Section on Biological Sciences American Association for the Advancement of Science, 2017-2020. Vice-president, Genetics Society of America, 2012. Vice-president, Society for the Study of Evolution, 1994. Council Member, Society for the Study of Evolution, 1991 – 1993.
    [Show full text]
  • Genetic and Maternal Effect Influences on Viability of Common Frog
    Heredity (2003) 91, 117–124 & 2003 Nature Publishing Group All rights reserved 0018-067X/03 $25.00 www.nature.com/hdy Genetic and maternal effect influences on viability of common frog tadpoles under different environmental conditions S Pakkasmaa1, J Merila¨2 and RB O’Hara2,3 1Department of Population Biology, Evolutionary Biology Centre, Uppsala University, Norbyva¨gen 18D, SE-75236 Uppsala, Sweden; 2Ecological Genetics Research Unit, Department of Ecology and Systematics, PO Box 65, FIN-00014 University of Helsinki, Finland; 3Rolf Nevanlinna Institute, PO Box 4, FIN-00014 University of Helsinki, Finland The influence of environmental stress on the expression of all traits were significant, independent of pH treatments and genetic and maternal effects on the viability traits has seldom typically of magnitude similar to the additive genetic effects. been assessed in wild vertebrates. We have estimated Maternal effects were large for all traits, especially for genetic and maternal effects on the viability (viz probability of viability itself, and their expression was partly dependent survival, probability of being deformed, and body size and on the environment. In the case of body size, the maternal shape) of common frog, Rana temporaria, tadpoles under effects were mediated largely through egg size. In general, stressful (low pH) and nonstressful (neutral pH) environ- the results give little evidence for the conjecture that mental conditions. A Bayesian analysis using generalized environmental stress created by low pH would impact linear mixed models was applied to data from a factorial strongly on the genetic architecture of fitness-related traits laboratory experiment. The expression of additive genetic in frogs, and hamper adaptation to stress caused by variance was independent of pH treatments, and all traits acidification.
    [Show full text]
  • Quantitative Genetics of Gene Expression and Methylation in the Chicken
    Andrey Höglund Linköping Studies In Science and Technology Dissertation No. 2097 FACULTY OF SCIENCE AND ENGINEERING Linköping Studies in Science and Technology, Dissertation No. 2097, 2020 Quantitative genetics Department of Physics, Chemistry and Biology Linköping University SE-581 83 Linköping, Sweden of gene expression Quantitative genetics of gene expression and methylation the in chicken www.liu.se and methylation in the chicken Andrey Höglund 2020 Linköping studies in science and technology, Dissertation No. 2097 Quantitative genetics of gene expression and methylation in the chicken Andrey Höglund IFM Biology Department of Physics, Chemistry and Biology Linköping University, SE-581 83, Linköping, Sweden Linköping 2020 Cover picture: Hanne Løvlie Cover illustration: Jan Sulocki During the course of the research underlying this thesis, Andrey Höglund was enrolled in Forum Scientium, a multidisciplinary doctoral program at Linköping University, Sweden. Linköping studies in science and technology, Dissertation No. 2097 Quantitative genetics of gene expression and methylation in the chicken Andrey Höglund ISSN: 0345-7524 ISBN: 978-91-7929-789-3 Printed in Sweden by LiU-tryck, Linköping, 2020 Abstract In quantitative genetics the relationship between genetic and phenotypic variation is investigated. The identification of these variants can bring improvements to selective breeding, allow for transgenic techniques to be applied in agricultural settings and assess the risk of polygenic diseases. To locate these variants, a linkage-based quantitative trait locus (QTL) approach can be applied. In this thesis, a chicken intercross population between wild and domestic birds have been used for QTL mapping of phenotypes such as comb, body and brain size, bone density and anxiety behaviour.
    [Show full text]
  • Maternal Variants in NLRP and Other Maternal Effect Proteins Are
    Epigenetics J Med Genet: first published as 10.1136/jmedgenet-2017-105190 on 24 March 2018. Downloaded from ORIGINAL ARTICLE Maternal variants in NLRP and other maternal effect proteins are associated with multilocus imprinting disturbance in offspring Matthias Begemann,1 Faisal I Rezwan,2 Jasmin Beygo,3 Louise E Docherty,4 Julia Kolarova,5 Christopher Schroeder,3 Karin Buiting,3 Kamal Chokkalingam,6 Franziska Degenhardt,7 Emma L Wakeling,8 Stephanie Kleinle,9 Daniela González Fassrainer,9 Barbara Oehl-Jaschkowitz,10 Claire L S Turner,11 Michal Patalan,12 Maria Gizewska,12 Gerhard Binder,13 Can Thi Bich Ngoc,14 Vu Chi Dung,14 Sarju G Mehta,15 Gareth Baynam,16,17 Julian P Hamilton-Shield,18 Sara Aljareh,2 Oluwakemi Lokulo-Sodipe,2,19 Rachel Horton,2,19 Reiner Siebert,5 Miriam Elbracht,1 Isabel Karen Temple,2,19 Thomas Eggermann,1 Deborah J G Mackay2 ► Additional material is ABSTRact overgrowth, macroglossia, exomphalos, hemihy- published online only. To view Background Genomic imprinting results from pertrophy and predisposition to Wilms tumour), please visit the journal online (http:// dx. doi. org/ 10. 1136/ the resistance of germline epigenetic marks to the growth restriction disorders Silver-Russell jmedgenet- 2017- 105190). reprogramming in the early embryo for a small syndrome (SRS; restricted growth, asymmetry and number of mammalian genes. Genetic, epigenetic or poor feeding) and Temple syndrome (TS; growth For numbered affiliations see environmental insults that prevent imprints from evading restriction, poor feeding, early puberty and obesity) end of article. reprogramming may result in imprinting disorders, which and transient neonatal diabetes mellitus (TNDM; impact growth, development, behaviour and metabolism.
    [Show full text]
  • Towards Population-Scale Long-Read Sequencing
    REVIEWS Towards population-scale long-read sequencing Wouter De Coster 1,2,5, Matthias H. Weissensteiner3,5 and Fritz J. Sedlazeck 4 ✉ Abstract | Long-read sequencing technologies have now reached a level of accuracy and yield that allows their application to variant detection at a scale of tens to thousands of samples. Concomitant with the development of new computational tools, the first population-scale studies involving long-read sequencing have emerged over the past 2 years and, given the continuous advancement of the field, many more are likely to follow. In this Review, we survey recent developments in population-scale long-read sequencing, highlight potential challenges of a scaled-up approach and provide guidance regarding experimental design. We provide an overview of current long-read sequencing platforms, variant calling methodologies and approaches for de novo assemblies and reference-based mapping approaches. Furthermore, we summarize strategies for variant validation, genotyping and predicting functional impact and emphasize challenges remaining in achieving long-read sequencing at a population scale. Genome-wide association Sequencing the DNA or mRNA of multiple individuals These studies highlighted that a substantial proportion studies of one or more species (that is, population-scale sequenc- of hidden variation can be discovered with long-read (GWAS). Studies involving a ing) aims to identify genetic variation at a population sequencing. Indeed, recent long-read sequencing stud- statistical approach in genetics level to address questions in the fields of evolutionary, ies of Icelandic and Chinese populations have already to identify variants that correlate with a certain agricultural and medical research. Previous popula- identified previously undetected variants associated with 11,12 phenotype (for example, a tion studies, including genome-wide association studies height, cholesterol level and anaemia .
    [Show full text]
  • An Introduction to Quantitative Genetics I Heather a Lawson Advanced Genetics Spring2018 Outline
    An Introduction to Quantitative Genetics I Heather A Lawson Advanced Genetics Spring2018 Outline • What is Quantitative Genetics? • Genotypic Values and Genetic Effects • Heritability • Linkage Disequilibrium and Genome-Wide Association Quantitative Genetics • The theory of the statistical relationship between genotypic variation and phenotypic variation. 1. What is the cause of phenotypic variation in natural populations? 2. What is the genetic architecture and molecular basis of phenotypic variation in natural populations? • Genotype • The genetic constitution of an organism or cell; also refers to the specific set of alleles inherited at a locus • Phenotype • Any measureable characteristic of an individual, such as height, arm length, test score, hair color, disease status, migration of proteins or DNA in a gel, etc. Nature Versus Nurture • Is a phenotype the result of genes or the environment? • False dichotomy • If NATURE: my genes made me do it! • If NURTURE: my mother made me do it! • The features of an organisms are due to an interaction of the individual’s genotype and environment Genetic Architecture: “sum” of the genetic effects upon a phenotype, including additive,dominance and parent-of-origin effects of several genes, pleiotropy and epistasis Different genetic architectures Different effects on the phenotype Types of Traits • Monogenic traits (rare) • Discrete binary characters • Modified by genetic and environmental background • Polygenic traits (common) • Discrete (e.g. bristle number on flies) or continuous (human height)
    [Show full text]
  • How We Are Evolving New Analyses Suggest That Recent Human Evolution Has Followed a Di!Erent Course Than Biologists Would Have Expected
    XXXXXXXX 40 Scientific American, October 2010 Photograph/Illustration by Artist Name © 2010 Scientific American Jonathan K. Pritchard is professor of human genetics at the University of Chicago and a Howard Hughes Medical Institute investigator. He studies genetic variation within and between human populations and the processes that led to this variation. E VO LU T I O N How We Are Evolving New analyses suggest that recent human evolution has followed a di!erent course than biologists would have expected By Jonathan K. Pritchard IN BRIEF As early Homo sapiens spread out from Many scientists thus expected that sur- ural selection—that is, because those nome contains some examples of very Africa starting around 60,000 years ago, veys of our genomes would reveal con- who carry the mutations have greater strong, rapid natural selection, most of they encountered environmental chal- siderable evidence of novel genetic mu- numbers of healthy babies than those the detectable natural selection appears lenges that they could not overcome tations that have recently spread quickly who do not. to have occurred at a far slower pace with prehistoric technology. ïà¹ù¹ùïmyày´ïȹÈù¨Dï¹´åUĂ´Dï- But it turns out that although the ge- than researchers had envisioned. Illustrations by Owen Gildersleeve October 2010, ScientificAmerican.com 41 © 2010 Scientific American !"#$%&'$ "( )*%+$ %," !#-%&$ -".*' ("+ /!* in technologies for studying genetic variation, we were able to first time into the Tibetan plateau, a vast ex- begin to address these questions. panse of steppelands that towers some 14,000 The work is still under way, but the preliminary findings have feet above sea level.
    [Show full text]