DOCSLIB.ORG

Grade 8 - Unit 5 - Natural Selection

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Grade 8 - Unit 5 - Natural Selection Grade 8 - Unit 5 - Natural Selection Unit Focus Through the examination of several natural phenomena related to the evolution of adaptation in organisms, students will craft evidence-based explanations for traits that enable organisms to survive in their environment. Students will engage in a variety of simulations and examine case studies as they uncover the principles of natural selection that result in large variety of differences within and between species. As a foundation to this study, students will learn the basics about the genetic code and how sexual reproduction and genetic mutation give rise to the variations that are crucial for the success of populations. Stage 1: Desired Results - Key Understandings Standard(s) Transfer Next Generation Science T1 Communicate effectively based on purpose, task, and audience to promote collective understanding and/or Middle School Life Science: 6 - 8 recommend actions. T2 Make observations and ask questions to define a problem based on prior knowledge and curiosity that stimulates Use argument based on empirical evidence and further exploration, analysis, and discovery. scientific reasoning to support an explanation for how characteristic animal behaviors and Meaning specialized plant structures affect the probability of successful reproduction of animals and plants Understanding(s) Essential Question(s) respectively. MS-LS1-4 Construct an explanation based on evidence that U1 Evolution results primarily from natural selection: Q1 Why do organisms seem to be so adapted to the places describes how genetic variations of traits in a genetic variation of individuals in a species, competition that they live? What happens when their environment population increase some individuals' probability for resources, and proliferation of organisms better able to changes? of surviving and reproducing in a specific survive and reproduce. Q2 How does the process of natural selection explain the environment. MS-LS4-4 U2 Natural selection leads to organisms with adaptations evolution of a species over time? (anatomical, behavioral, and physiological) that are well Q3 How does sexual reproduction lead to variation Next Generation Science Standards (DCI) suited to survival and reproduction in a particular between parents and offspring? Science: 8 environment. Q4 What impact can mutations have on living things? U3 Species can change over time in response to changes in environmental conditions through natural selection Animals engage in characteristic behaviors that acting over generations. Traits that support successful increase the odds of reproduction. LS1.6.B1 survival and reproduction in the new environment become Organisms reproduce, either sexually or asexually, more common. and transfer their genetic information to their U4 The distribution of traits in a population, as well as offspring. LS1.6.B2 species expansion, emergence or extinction, can change Genes are located in the chromosomes of cells, when conditions change. with each chromosome pair containing two U5 Organisms reproduce, either sexually or asexually, and variants of each of many distinct genes. Each transfer their genetic information to their offspring. Madison Public Schools | July 2019 1 Stage 1: Desired Results - Key Understandings distinct gene chiefly controls the production of U6 The variation and distribution of traits in a population specific proteins, which in turn affects the traits of depend on genetic and environmental factors. the individual. Changes (mutations) to genes can U7 Organisms inherit chromosomes from their parents result in changes to proteins, which can affect the containing genes that code for different proteins which structures and functions of the organism and affect an individual’s traits. thereby change traits. LS3.6.A1 U8 Genetic information can be altered because of Variations of inherited traits between parent and mutations, which may result in beneficial, negative, or no offspring arise from genetic differences that result change to the proteins and traits of an organism. from the subset of chromosomes (and therefore U9 Natural selection occurs only if there is variation in the genes) inherited. LS3.6.A2 genes and associated traits between individuals in a In addition to variations that arise from sexual population. Traits that positively affect survival can reproduction, genetic information can be altered become more common in a population. because of mutations. Though rare, mutations may result in changes to the structure and function of Acquisition of Knowledge and Skill proteins. Some changes are beneficial, others harmful, and some neutral to the organism. Knowledge Skill(s) LS3.6.B2 Natural selection leads to the predominance of K1 Natural selection is the process that explains how S1 Applying the principles of natural selection to explain certain traits in a population, and the suppression of certain traits in populations arose. how adaptations in organisms evolve. others. LS4.6.B1 K2 Charles Darwin's observations of the slight variations S2 Apply knowledge to develop a prediction or a claim Adaptation by natural selection acting over in organisms along the South American coast and the that is justified by evidence. generations is one important process by which Galapagos Islands is an example of how scientific S3 Analyzing a case study and synthesizing concepts to species change over time in response to changes in observations and inferences can explain natural develop a scientifically-based explanation. environmental conditions. Traits that support phenomena. successful survival and reproduction in the new K3 Favorable variations are those traits that help an environment become more common; those that do organism to survive and reproduce, thereby passing on the not become less common. Thus, the distribution of genes for this trait to their offspring. traits in a population changes. LS4.6.C1 K4 When an organism has a favorable variation/trait that makes them more likely to survive to reproduce and pass Student Growth and Development 21st Century on the genes for this trait, it is likely that the trait will Capacities Matrix become more common in a population. Critical Thinking K5 When environments change, species adapt, flee, or die. Analyzing: Students will be able to examine K6 When environments change, sometimes a trait information/data/evidence to make inferences and becomes more favorable and thereby becomes more identify possible underlying assumptions, patterns, common in the population over time. and relationships. MM.1.2 K7 Organisms cannot "will" themselves to change, rather, Synthesizing: Students will be able to thoughtfully the variations in traits that they possess make them more combine information/data/evidence, concepts, or less likely to survive, reproduce, and pass the genes for texts, and disciplines to draw conclusions, create their variations onto their offspring. Madison Public Schools | July 2019 2 Stage 1: Desired Results - Key Understandings solutions, and/or verify generalizations for a given K8 Evolution occurs in species over a very long period of purpose. MM.1.3 time and can result in the formation of new species. K9 Genetic variation can result from sexual reproduction and mutations. K10 Sexual reproduction is primarily responsible for variation in populations because it scrambles the genes in a person and then combines these genes with another. K11 Genes are located on chromosomes in cells. K12 The genetic code of all organisms is comprised of A, T, C, and G bases in a particular sequence. If this sequence is changed due to a mutation, it can change the traits of an organism. K13 Genetic mutations can result in changes to the proteins produced thereby changing traits. K14 Genetic mutations can have a negative, positive, or neutral effect an on organisms traits (physical and behavioral). K15 Natural Selection Vocabulary: meiosis, sexual reproduction, genes, chromosomes, natural selection, evolution, genetic diversity, population, variations, fitness of genes, adaptation (Physical/Behavioral), mutation, genetic code Madison Public Schools | July 2019 3 .
Load more

Recommended publications
  • Random Mutation and Natural Selection in Competitive and Non-Competitive Environments
    ISSN: 2574-1241 Volume 5- Issue 4: 2018 DOI: 10.26717/BJSTR.2018.09.001751 Alan Kleinman. Biomed J Sci & Tech Res Mini Review Open Access Random Mutation and Natural Selection In Competitive and Non-Competitive Environments Alan Kleinman* Department of Medicine, USA Received: : September 10, 2018; Published: September 18, 2018 *Corresponding author: Alan Kleinman, PO BOX 1240, Coarsegold, CA 93614, USA Abstract Random mutation and natural selection occur in a variety of different environments. Three of the most important factors which govern the rate at which this phenomenon occurs is whether there is competition between the different variants for the resources of the environment or not whether the replicator can do recombination and whether the intensity of selection has an impact on the evolutionary trajectory. Two different experimental models of random mutation and natural selection are analyzed to determine the impact of competition on random mutation and natural selection. One experiment places the different variants in competition for the resources of the environment while the lineages are attempting to evolve to the selection pressure while the other experiment allows the lineages to grow without intense competition for the resources of the environment while the different lineages are attempting to evolve to the selection pressure. The mathematics which governs either experiment is discussed, and the results correlated to the medical problem of the evolution of drug resistance. Introduction important experiments testing the RMNS phenomenon. And how Random mutation and natural selection (RMNS) are a does recombination alter the evolutionary trajectory to a given phenomenon which works to defeat the treatments physicians use selection pressure? for infectious diseases and cancers.
    [Show full text]
  • The Evolutionary Biology of Decision Making
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Faculty Publications, Department of Psychology Psychology, Department of 2008 The Evolutionary Biology of Decision Making Jeffrey R. Stevens University of Nebraska-Lincoln, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/psychfacpub Part of the Psychiatry and Psychology Commons Stevens, Jeffrey R., "The Evolutionary Biology of Decision Making" (2008). Faculty Publications, Department of Psychology. 523. https://digitalcommons.unl.edu/psychfacpub/523 This Article is brought to you for free and open access by the Psychology, Department of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Faculty Publications, Department of Psychology by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Published in BETTER THAN CONSCIOUS? DECISION MAKING, THE HUMAN MIND, AND IMPLICATIONS FOR INSTITUTIONS, ed. Christoph Engel and Wolf Singer (Cambridge, MA: The MIT Press, 2008), pp. 285-304. Copyright 2008 Massachusetts Institute of Technology & the Frankfurt Institute for Advanced Studies. Used by permission. 13 The Evolutionary Biology of Decision Making Jeffrey R. Stevens Center for Adaptive Behavior and Cognition, Max Planck Institute for Human Development, 14195 Berlin, Germany Abstract Evolutionary and psychological approaches to decision making remain largely separate endeavors. Each offers necessary techniques and perspectives which, when integrated, will aid the study of decision making in both humans and nonhuman animals. The evolutionary focus on selection pressures highlights the goals of decisions and the con­ ditions under which different selection processes likely influence decision making. An evolutionary view also suggests that fully rational decision processes do not likely exist in nature.
    [Show full text]
  • Plant Evolution an Introduction to the History of Life
    Plant Evolution An Introduction to the History of Life KARL J. NIKLAS The University of Chicago Press Chicago and London CONTENTS Preface vii Introduction 1 1 Origins and Early Events 29 2 The Invasion of Land and Air 93 3 Population Genetics, Adaptation, and Evolution 153 4 Development and Evolution 217 5 Speciation and Microevolution 271 6 Macroevolution 325 7 The Evolution of Multicellularity 377 8 Biophysics and Evolution 431 9 Ecology and Evolution 483 Glossary 537 Index 547 v Introduction The unpredictable and the predetermined unfold together to make everything the way it is. It’s how nature creates itself, on every scale, the snowflake and the snowstorm. — TOM STOPPARD, Arcadia, Act 1, Scene 4 (1993) Much has been written about evolution from the perspective of the history and biology of animals, but significantly less has been writ- ten about the evolutionary biology of plants. Zoocentricism in the biological literature is understandable to some extent because we are after all animals and not plants and because our self- interest is not entirely egotistical, since no biologist can deny the fact that animals have played significant and important roles as the actors on the stage of evolution come and go. The nearly romantic fascination with di- nosaurs and what caused their extinction is understandable, even though we should be equally fascinated with the monarchs of the Carboniferous, the tree lycopods and calamites, and with what caused their extinction (fig. 0.1). Yet, it must be understood that plants are as fascinating as animals, and that they are just as important to the study of biology in general and to understanding evolutionary theory in particular.
    [Show full text]
  • Evolution by Natural Selection, Formulated Independently by Charles Darwin and Alfred Russel Wallace
    UNIT 4 EVOLUTIONARY PATT EVOLUTIONARY E RNS AND PROC E SS E Evolution by Natural S 22 Selection Natural selection In this chapter you will learn that explains how Evolution is one of the most populations become important ideas in modern biology well suited to their environments over time. The shape and by reviewing by asking by applying coloration of leafy sea The rise of What is the evidence for evolution? Evolution in action: dragons (a fish closely evolutionary thought two case studies related to seahorses) 22.1 22.4 are heritable traits that with regard to help them to hide from predators. The pattern of evolution: The process of species have changed evolution by natural and are related 22.2 selection 22.3 keeping in mind Common myths about natural selection and adaptation 22.5 his chapter is about one of the great ideas in science: the theory of evolution by natural selection, formulated independently by Charles Darwin and Alfred Russel Wallace. The theory explains how T populations—individuals of the same species that live in the same area at the same time—have come to be adapted to environments ranging from arctic tundra to tropical wet forest. It revealed one of the five key attributes of life: Populations of organisms evolve. In other words, the heritable characteris- This chapter is part of the tics of populations change over time (Chapter 1). Big Picture. See how on Evolution by natural selection is one of the best supported and most important theories in the history pages 516–517. of scientific research.
    [Show full text]
  • Local Drift Load and the Heterosis of Interconnected Populations
    Heredity 84 (2000) 452±457 Received 5 November 1999, accepted 9 December 1999 Local drift load and the heterosis of interconnected populations MICHAEL C. WHITLOCK*, PAÈ R K. INGVARSSON & TODD HATFIELD Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4 We use Wright's distribution of equilibrium allele frequency to demonstrate that hybrids between populations interconnected by low to moderate levels of migration can have large positive heterosis, especially if the populations are small in size. Bene®cial alleles neither ®x in all populations nor equilibrate at the same frequency. Instead, populations reach a mutation±selection±drift±migration balance with sucient among-population variance that some partially recessive, deleterious mutations can be masked upon crossbreeding. This heterosis is greatest with intermediate mutation rates, intermediate selection coecients, low migration rates and recessive alleles. Hybrid vigour should not be taken as evidence for the complete isolation of populations. Moreover, we show that heterosis in crosses between populations has a dierent genetic basis than inbreeding depression within populations and is much more likely to result from alleles of intermediate eect. Keywords: deleterious mutations, heterosis, hybrid ®tness, inbreeding depression, migration, population structure. Introduction genetic drift, producing ospring with higher ®tness than the parents (see recent reviews on inbreeding in Crow (1948) listed several reasons why crosses between Thornhill, 1993). Decades of work in agricultural individuals from dierent lines or populations might genetics con®rms this pattern: when divergent lines are have increased ®tness relative to more `pure-bred' crossed their F1 ospring often perform substantially 1individuals, so-called `hybrid vigour'. Crow commented better than the average of the parents (Falconer, 1981; on many possible mechanisms behind hybrid vigour, Mather & Jinks, 1982).
    [Show full text]
  • Adaptive Tuning of Mutation Rates Allows Fast Response to Lethal Stress In
    Manuscript 1 Adaptive tuning of mutation rates allows fast response to lethal stress in 2 Escherichia coli 3 4 a a a a a,b 5 Toon Swings , Bram Van den Bergh , Sander Wuyts , Eline Oeyen , Karin Voordeckers , Kevin J. a,b a,c a a,* 6 Verstrepen , Maarten Fauvart , Natalie Verstraeten , Jan Michiels 7 8 a 9 Centre of Microbial and Plant Genetics, KU Leuven - University of Leuven, Kasteelpark Arenberg 20, 10 3001 Leuven, Belgium b 11 VIB Laboratory for Genetics and Genomics, Vlaams Instituut voor Biotechnologie (VIB) Bioincubator 12 Leuven, Gaston Geenslaan 1, 3001 Leuven, Belgium c 13 Smart Systems and Emerging Technologies Unit, imec, Kapeldreef 75, 3001 Leuven, Belgium * 14 To whom correspondence should be addressed: Jan Michiels, Department of Microbial and 2 15 Molecular Systems (M S), Centre of Microbial and Plant Genetics, Kasteelpark Arenberg 20, box 16 2460, 3001 Leuven, Belgium, [email protected], Tel: +32 16 32 96 84 1 Manuscript 17 Abstract 18 19 While specific mutations allow organisms to adapt to stressful environments, most changes in an 20 organism's DNA negatively impact fitness. The mutation rate is therefore strictly regulated and often 21 considered a slowly-evolving parameter. In contrast, we demonstrate an unexpected flexibility in 22 cellular mutation rates as a response to changes in selective pressure. We show that hypermutation 23 independently evolves when different Escherichia coli cultures adapt to high ethanol stress. 24 Furthermore, hypermutator states are transitory and repeatedly alternate with decreases in mutation 25 rate. Specifically, population mutation rates rise when cells experience higher stress and decline again 26 once cells are adapted.
    [Show full text]
  • Microevolution and the Genetics of Populations ​ ​ Microevolution Refers to Varieties Within a Given Type
    Chapter 8: Evolution Lesson 8.3: Microevolution and the Genetics of Populations ​ ​ Microevolution refers to varieties within a given type. Change happens within a group, but the descendant is clearly of the same type as the ancestor. This might better be called variation, or adaptation, but the changes are "horizontal" in effect, not "vertical." Such changes might be accomplished by "natural selection," in which a trait ​ ​ ​ ​ within the present variety is selected as the best for a given set of conditions, or accomplished by "artificial selection," such as when dog breeders produce a new breed of dog. Lesson Objectives ● Distinguish what is microevolution and how it affects changes in populations. ● Define gene pool, and explain how to calculate allele frequencies. ● State the Hardy-Weinberg theorem ● Identify the five forces of evolution. Vocabulary ● adaptive radiation ● gene pool ● migration ● allele frequency ● genetic drift ● mutation ● artificial selection ● Hardy-Weinberg theorem ● natural selection ● directional selection ● macroevolution ● population genetics ● disruptive selection ● microevolution ● stabilizing selection ● gene flow Introduction Darwin knew that heritable variations are needed for evolution to occur. However, he knew nothing about Mendel’s laws of genetics. Mendel’s laws were rediscovered in the early 1900s. Only then could scientists fully understand the process of evolution. Microevolution is how individual traits within a population change over time. In order for a population to change, some things must be assumed to be true. In other words, there must be some sort of process happening that causes microevolution. The five ways alleles within a population change over time are natural selection, migration (gene flow), mating, mutations, or genetic drift.
    [Show full text]
  • Investigating VIST Evolutionary Principles (Variation, Inheritance, Selection & Time)
    Exploring the KU Natural History Museum Investigating VIST Evolutionary Principles (Variation, Inheritance, Selection & Time) Target Audience: Middle school and above Differentiated Instruction Summary Content/ Strategy Levels Process/ Grouping(s)* Product Readiness Small groups Content Level 1 – VIST principles in Explore Peer partners Cubing Process Evolution exhibit (organized around VIST) Homogeneous Product Level 2 – VIST principles in other exhibits Heterogeneous * Varied grouping options can be used for this activity, depending on student needs and chaperone ability. Objective: Investigate the evolutionary principles of variation, inheritance, selection and time. Pre-assessment/Prior Knowledge: Prior to their visit, students should be familiar with the four evolutionary principles of variation, inheritance, selection and time (VIST). Activity Description: Students explore the four principles of evolution: variation, inheritance selection and time through museum exhibits. In Level 1, students explore these four principles in the Explore Evolution exhibit. This exhibit presents evolutionary research across seven different organisms, from the smallest to the very large, and is organized around (and explicitly addresses) the VIST principles work in each organism. In Level 2, students apply the VIST principles to exhibits on various floors, most of which do not explicitly use this framework. Materials Needed: • Student o Cubes (three levels, see attached) o Notebooks/paper and pencils Note: Format to record/present findings determined by individual teacher. Provide clear instructions about expectations for documenting participation. • Teacher o Content Outline o Cube labels o Cube template © The University of Kansas Natural History Museum (2014) Exploring the KU Natural History Museum Content: VIST* Overview There are four principles at work in evolution—variation, inheritance, selection and time.
    [Show full text]
  • Information Systems Theorizing Based on Evolutionary Psychology: an Interdisciplinary Review and Theory Integration Framework1
    Kock/IS Theorizing Based on Evolutionary Psychology THEORY AND REVIEW INFORMATION SYSTEMS THEORIZING BASED ON EVOLUTIONARY PSYCHOLOGY: AN INTERDISCIPLINARY REVIEW AND THEORY INTEGRATION FRAMEWORK1 By: Ned Kock on one evolutionary information systems theory—media Division of International Business and Technology naturalness theory—previously developed as an alternative to Studies media richness theory, and one non-evolutionary information Texas A&M International University systems theory, channel expansion theory. 5201 University Boulevard Laredo, TX 78041 Keywords: Information systems, evolutionary psychology, U.S.A. theory development, media richness theory, media naturalness [email protected] theory, channel expansion theory Abstract Introduction Evolutionary psychology holds great promise as one of the possible pillars on which information systems theorizing can While information systems as a distinct area of research has take place. Arguably, evolutionary psychology can provide the potential to be a reference for other disciplines, it is the key to many counterintuitive predictions of behavior reasonable to argue that information systems theorizing can toward technology, because many of the evolved instincts that benefit from fresh new insights from other fields of inquiry, influence our behavior are below our level of conscious which may in turn enhance even more the reference potential awareness; often those instincts lead to behavioral responses of information systems (Baskerville and Myers 2002). After that are not self-evident. This paper provides a discussion of all, to be influential in other disciplines, information systems information systems theorizing based on evolutionary psych- research should address problems that are perceived as rele- ology, centered on key human evolution and evolutionary vant by scholars in those disciplines and in ways that are genetics concepts and notions.
    [Show full text]
  • •How Does Microevolution Add up to Macroevolution? •What Are Species
    Microevolution and Macroevolution • How does Microevolution add up to macroevolution? • What are species? • How are species created? • What are anagenesis and cladogenesis? 1 Sunday, March 6, 2011 Species Concepts • Biological species concept: Defines species as interbreeding populations reproductively isolated from other such populations. • Evolutionary species concept: Defines species as evolutionary lineages with their own unique identity. • Ecological species concept: Defines species based on the uniqueness of their ecological niche. • Recognition species concept: Defines species based on unique traits or behaviors that allow members of one species to identify each other for mating. 2 Sunday, March 6, 2011 Reproductive Isolating Mechanisms • Premating RIMs Habitat isolation Temporal isolation Behavioral isolation Mechanical incompatibility • Postmating RIMs Sperm-egg incompatibility Zygote inviability Embryonic or fetal inviability 3 Sunday, March 6, 2011 Modes of Evolutionary Change 4 Sunday, March 6, 2011 Cladogenesis 5 Sunday, March 6, 2011 6 Sunday, March 6, 2011 7 Sunday, March 6, 2011 Evolution is “the simple way by which species (populations) become exquisitely adapted to various ends” 8 Sunday, March 6, 2011 All characteristics are due to the four forces • Mutation creates new alleles - new variation • Genetic drift moves these around by chance • Gene flow moves these from one population to the next creating clines • Natural selection increases and decreases them in frequency through adaptation 9 Sunday, March 6, 2011 Clines
    [Show full text]
  • The Biological Roots of Morality*
    The Biological Roots of Morality* FRANCISCO J. AYALA Department of Genetics University of California Davis, California 95616 U.S.A. ABSTRACT: The question whether ethical behavior is biologically determined may refer either to the capacity for ethics (i.e., the proclivity to judge human actions as either right or wrong), or to the moral norms accepted by human beings for guiding their actions. My theses are: (1) that the capacity for ethics is a necessary attribute of human nature; and (2) that moral norms are products of cultural evolution, not of biological evolution. Humans exhibit ethical behavior by nature because their biological makeup determines the presence of the three necessary, and jointly sufficient, conditions for ethical behavior: (i) the ability to anticipate the consequences of one's own actions; (ii) the ability to make value judgments; and (iii) the ability to choose between alternative courses of action. Ethical behavior came about in evolution not because it is adaptive in itself, but as a necessary consequence of man's eminent intellectual abilities, which are an attribute directly promoted by natural selection. Since Darwin's time there have been evolutionists proposing that the norms of morality are derived from biological evolution. Sociobiologists represent the most recent and most subtle version of that proposal. The sociobiologists' argument is that human ethical norms are sociocultural correlates of behaviors fostered by biological evolution. I argue that such proposals are misguided and do not escape the naturalistic fallacy. The isomorphism between the behaviors promoted by natural selection and those sanctioned by moral norms exists only with respect to the consequences of the behaviors; the underlying causations are completely disparate.
    [Show full text]
  • Mutation Versus Variant?
    GUEST EDITORIAL Garry Cutting What’s in a Name: Mutation versus Variant? Effective communication between scientists and the public requires word (Condit et al., 2002). The problem of inferring delete- the use of words that have well-understood meanings. Similarly, rious consequences when using the term “mutation” is that some use of a word that means one thing to scientists but something changes in DNA are advantageous from an evolutionary point Downloaded from http://online.ucpress.edu/abt/article-pdf/77/3/160/58360/abt_2015_77_3_1.pdf by guest on 02 October 2021 else to the lay public can lead to confusion. This situation can arise of view. On the other hand, “variant” is usually defined in terms when words change in their meaning over time in scientific cir- of an organism that differs in some way from an accepted stan- cles but not among the public, and vice versa. On occasion, disso- dard. “Variant” can also be used for phenotypic differences that nance between scientific and societal definitions can cause terms to are not genetic (King & Stansfield, 2002). The application of the acquire a stigma. This issue is particularly important when scientific term “variant” to changes in DNA structure was popularized by terms are used in medical situations. Certain words may invoke genome-wide association studies of common disorders. “Variant” a very different impression for a patient than was intended by a as opposed to “mutation” is preferred because most of the DNA medical professional. For example, the term “mental retardation” alterations that contribute risk to complex genetic conditions are is defined scientifically on the basis of the population distribution of unknown effect and are frequent in the population.
    [Show full text]