DOCSLIB.ORG

Evolutionary and Ecological Genetics 3M 1995/6

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Evolutionary and Ecological Genetics 3M 1995/6 Evolutionary and Ecological Genetics Course Guide 2020/2021 Course Overview 3 Learning outcomes from this course 3 Learning outcomes will be achieved through: 4 Staff 4 Course Organiser 4 Course Secretary 4 Lecturers 4 Teaching Period 5 Course Background 5 Possible Honours Courses 5 Workload Expectation 5 Assessment and Deadlines 5 Continuous assessment and essay [50%] 5 Examination [50%] 6 Assessment Policy 6 Adjustment schedules 6 LEARN discussion boards and open ‘Collaborate’ room 7 Representation, Feedback and Appeals 7 EEG timetable and checklist 2020-2021 8 Reading Material 12 Pre-recorded Lecture Modules 13 Introduction to the course (DJO) 13 Population genetics and molecular evolution (DJO) 13 Module 1: Mutations, Diversity and Drift 14 Module 2: Natural Selection 16 Page | 1 Module 3: Balancing Selection and Population structure 18 Module 4: Sex and Recombination 20 Genetics of Complex Traits (Craig Walling) 21 Module 5: Introduction to the genetics of complex traits and heritability 21 Module 6. Estimation of heritability and an introduction to selection on complex traits 23 Module 7. The nature of complex trait variation 24 Module 8: Molecular Phylogenetics (Paul Sharp) 25 8.1 Introduction to phylogenetics 25 Module 9: Speciation (Simon Martin) 26 Module 10: Genetic parasites (Darren Obbard) 27 Computer Practicals and Quizzes 28 Problem Tutorial Sessions 28 In-course Essay 29 Part 1: What makes a good essay? 29 Part 2: Engagement with the starter-references [3%] 29 Part 3: Writing the Essay [27%] 30 Essay Titles 31 Appendix – Practical advice for essay writing 36 Further Information 39 Page | 2 Course Overview This course will introduce you to the processes that underlie evolutionary change in natural populations. It is intended to give an integrated view, showing how theoretical approaches can be applied to investigate natural evolutionary processes. We will deal with subjects ranging from the evolutionary fate of molecular sequences to the genetic consequences of interactions between species, and from variation at single genes to speciation. The course starts with population genetics and molecular evolution (Weeks 1-4) emphasising its importance in understanding the process of biological evolution. This is followed by an introduction to the genetics of quantitative characters (Weeks 5-7). The course ends with lecture modules on molecular phylogenetics, mechanisms of speciation, and genetic parasites (Weeks 8-10). The first three sections of the course are associated with computer-based practical classes (which are assessed through digital quizzes online) and live digital “problem” tutorials. These sessions are designed to assist with understanding of key concepts, to give practice in problem solving and to develop competence in quantitative analysis. An essay and associated tutorials provide the opportunity for assimilating and synthesising information from the primary literature and discussing its interpretation. Learning outcomes from this course University of Edinburgh courses follow the Scottish Credit and Qualification Framework (SCQF), which has 12 levels for each of 6 specified ‘characteristics’. 1) Knowledge and Understanding Know that Biological Evolution is the result of interaction between processes such as mutation, genetic drift, natural selection, migration, and recombination, and understand in qualitative terms how these processes occur and interact 2) Practice: Applied Knowledge, Skills and Understanding Be able to apply simple equations and statistical methods to quantify the processes that underlie evolution, and to test for departures from neutral or null expectations 3) Generic Cognitive Skills Be able to integrate distinct views of the evolutionary process, and to assess and evaluate the assumptions behind models and model-based analyses 4) Communication, ICT, and Numeracy Use graphs to display and interpret genetic and phenotypic data in an evolutionary or ecological context, and use simple statistical methods such as the chi-squared test, regression and ANOVA to analyse them. 5) Autonomy, Accountability, and Working with others Be able to work in small groups to propose and evaluate standard methods for analysing genetic and phenotypic data in an evolutionary or ecological context, and present your solutions and reasoning to peers. EEG3 is a level 9-10 course (Ordinary to Honours degree level). Page | 3 Learning outcomes will be achieved through: Pre-recorded lecture modules and live digital discussions the basic concepts and quantitative foundation of population genetics the importance of population genetics in population management how molecular evolution links evolutionary biology and population genetics what can be learned about natural selection through molecular population genetics the fundamentals of quantitative genetics Live digital computer practical classes to study the use of computer simulations to understand the behaviour of genes in populations to become familiar with phylogenetic analysis of molecular sequence data to become familiar with experimental and analytical techniques in current use in evolutionary genetics to appreciate the importance of statistical techniques in the analysis and interpretation of biological and genetic data Live digital problem sessions and discussion to develop skills in solving quantitative problems in evolutionary genetics Essay writing to develop skills in understanding, assimilating and presenting scientific arguments in a critical and original fashion Staff Course Organiser Dr. Darren Obbard (Institute of Evolutionary Biology) Ashworth 2, room 2.09, [email protected] Course Secretary Janna James (BTO) for any questions regarding times, dates, deadlines, rooms or paperwork, please email [email protected] Lecturers Dr. Darren Obbard (IEB) ([email protected]) Dr. Craig Walling (IEB) ([email protected] ) Prof. Paul Sharp (IEB) ([email protected]) Dr. Simon Martin (IEB) ([email protected]) All teaching staff are actively involved in research in evolutionary genetics. Our areas of research are described below (use the pdf version of this document to access the hyperlinks!): Darren Obbard link Genome evolution (invertebrates, RNAi and viruses) Craig Walling link Quantitative genetics and life history evolution (red deer, Drosophila) Simon Martin link Population genomics and speciation in Butterflies Paul Sharp link Molecular evolution (viruses, malaria parasites) Course email address (for all general enquiries) - [email protected] Page | 4 Teaching Period Semester 1 Course Background Preferred background: Evolution in Action 2 Possible Honours Courses The course is appropriate for students intending to take any one of a wide range of Honours courses, including Evolutionary Biology, Zoology, Ecology, Genetics, Molecular Genetics, and Plant Sciences. Workload Expectation This is a 20 credit course, which is intended to equate to 200 hours of your time. We think a reasonable breakdown of those 200 hours could be: Component Approximate number Total time Watching pre-recorded lecture modules 10 x 2h 20h Answering lecture module practice quizzes 10 x 3h 30h Attending live Q&A sessions 20 x 1h 20h Computer practicals & assessed quizzes 5 x 3h 15h Problem sessions & practice quizzes 5 x 3h 15h Course essay preparation 30h Writing the course essay 20h Reading, Revision, and Exam practice 50h Total 200h Assessment and Deadlines Continuous assessment contributes 50% of the total marks for the course. The open-book examination, which will be taken within a 24-hour window at the end of the semester, contributes the other 50%. Continuous assessment and essay [50%] The continuous assessment marks comprise 27% for the in-course essay, 3% for engagement with the essay reading, and 20% for four short online quizzes associated with computer practicals (5% each). Questions for the assessed practicals are directly related to the practical questions, and should only take a few minutes. Note that the quiz for practical 1 does not count towards your overall course mark, but it is still important, as this is an opportunity to practice. Also remember that the more challenging lecture-module and problem-session quizzes are not assessed – those are just to help you learn The course essay must be submitted in electronic form through turnitin, using your exam number for identification. Deadlines for submission are provided via LEARN. Marked and annotated essays will be returned electronically Any hard-copy submissions must have a barcode attached. Page | 5 Examination [50%] The examination will be done digitally, open-book, in a 24-hour window toward the end of semester 1. This means that there will be little time for revision between the end of the course and the examination. You are therefore encouraged to learn the course material as you go along. The examination paper will contain 3 sections. Section 1 will be done electronically online. It will contain two equally weighted quantitative / calculation ‘problem’ questions, both of which must be answered. [20%] Section 2 will be done offline. It will contain two short answer questions, and one of these questions must be answered. [15%] Section 3 will be done offline. It will contain two short answer questions, and one of these questions must be answered. [15%] Material will be distributed between sections 2 and 3 to ensure that questions covering both population-genetics (molecular evolution) and quantitative genetics must be answered. Note that this is a new structure from 2020 onward, and
Load more

Recommended publications
  • Qrup: 127E; Fənn: Ecological Genetics İmtahan Sualları (2021-Ci Il, Tədris Yükü (Saat) Cəmi: 90 Saat; Mühazirə 45 Saat; Məşğələ 45 Saat)
    Bakı Dövlət Universiteti Biologiya fakültəsi; Qrup: 127E; Fənn: Ecological genetics İmtahan sualları (2021-ci il, tədris yükü (saat) cəmi: 90 saat; mühazirə 45 saat; məşğələ 45 saat) 1. The subject of Ecological genetics, its main problems 2. The theoretical and practical problems of Ecological genetics 3. Brief history of Ecological genetics 4. The investigation methods of Ecological genetics 5. Conception of adaptation, adaptive reaction norm 6. The role of modifications and genotypic variations in adaptation 7. Different types of adaptations 8. Ontogenetic and phylogenetic adaptations 9. Population-species adaptations and adaptations in biogeocenosis 10. Adaptive traits of biological systems: plasticity, flexibility, stability, homeostasis, genetic homeostasis and canalization 11. Genetic diversity, its types; significance of conservation of genetic diversity 12. Genetic erosion, its causes and results 13. Genetic effects of population fragmentation, population size, inbreeding and gene flow 14. Population bottleneck and fonder effect 15. Conservation methods of genetic diversity 16. Evolution as a consequence of changes in alleles and allele frequencies in populations over time 17. Factors affecting allele frequencies and genetic equilibrium in populations 18. Genetic nature of adaptive reactions 19. Role of heterozygosity and polymorphism in adaptation 20. Explaining the high level of genetic variation in populations 21. Detecting genetic variation by artificial selection and genetic markers 22. Polymerase chain reaction (PCR); its steps, limits, types and applications 23. Integration of adaptive reactions 24. Role of supergenes and gene-complexes in adaptation 25. Heterostyly, its role in adaptation 26. Genetic regulation mechanisms of adaptive traits 27. Effects of environmental factors on gene expression in prokaryotes; the operon model of regulation 28.
    [Show full text]
  • Ecological Genetics of Freshwater Fish: a Short Review of the Genotype–Phenotype Connection
    Animal Biodiversity and Conservation 34.2 (2011) Review309 Ecological genetics of freshwater fish: a short review of the genotype–phenotype connection O. Vidal & J. L. García–Marín Vidal, O. & García–Marín, J. L., 2011. Ecological genetics of freshwater fish: a short review of the genotype– phenotype connection. Animal Biodiversity and Conservation, 34.2: 309–317. Abstract Ecological genetics of freshwater fish: a short review of the genotype–phenotype connection.— Molecular eco- logy or ecological genetics is an expanding application of population genetics which has flourished in the last two decades but it is dominated by systematic and phylogeographic studies, with relatively little emphasis on the study of the genetic basis of the process of adaptation to different ecological conditions. The relationship between genotype and adaptive phenotypes is weak because populations are often difficult to quantify and experiments are logistically challenging or unfeasible. Interestingly, in freshwater fish, studies to characterize the genetic architecture of adaptive traits are not as rare as in other vertebrate groups. In this review, we summarize the few cases where the relationship between the ecology and genetics of freshwater fish is more developed, namely the relationship between genetic markers and ecological phenotypes. Key words: Ecological genetics, Molecular ecology, Genotype–phenotype relationship, Adaptation, Landscape genetics, Species introduction. Resumen Genética ecológica de los peces de agua dulce: una breve revisión de la conexión genotipo–fenotipo.— La ecología molecular o la genética ecológica es una aplicación de la genética de poblaciones que durante las dos últimas décadas ha sufrido un proceso de expansión. Sin embargo, en la ecología molecular predominan los estudios sistemáticos y filogeográficos, con relativamente poco énfasis en el análisis de la base genética del proceso de adaptación a diferentes condiciones ecológicas.
    [Show full text]
  • IB 162 Ecological Genetics University of California, Berkeley Department of Integrative Biology (4 Units)
    Ecological Genetics Integrative Biology 162 IB 162 Ecological Genetics University of California, Berkeley Department of Integrative Biology (4 units) Course Description: This course presents modern approaches to studying evolution in natural populations, which requires both ecology and genetics. We will study quantitative and molecular causes of inheritance of ecologically important traits and their evolution. We will use simple mathematical models to predict evolution in natural populations. This course will help you build a conceptual framework for understanding biology. "Nothing in biology makes sense except in the light of evolution." . Theodosius Dobzhansky (1970) Genetics of the Evolutionary Process Format: There are lecture and discussion sessions. Lectures will focus primarily on broad concepts and ideas. Weekly discussion sections will help you master ideas and give you practice in reading and analyzing primary scientific literature. Lectures: TBD Discussions: TBD Goals: 1. Students will understand how genes and environments interact to produce phenotypes, including biological fitness, and influence which alleles are passed on to the next generation. 2. Mathematical models make our assumptions explicit. We will develop and apply simple mathematical models for studying evolution in natural populations. 3. Students will improve their ability to ask questions and answer them using scientific methods. 4. Students will gain factual knowledge of terms and concepts used to study evolution in natural populations. Instructors and their contact information. TBD Office hours are the best way to get help and feedback. If you have a complicated question, are struggling to understand something, or want to dive deeper, come to office hours of the professor or the GSI. Grade Breakdown Activity (see below for details) Points Discussion section quizzes (5 @ 2 pts.
    [Show full text]
  • Role of Sexual Imprinting in Assortative Mating and Premating Isolation in Darwin’S Finches
    Role of sexual imprinting in assortative mating and premating isolation in Darwin’s finches Peter R. Granta,1 and B. Rosemary Granta aDepartment of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544 Contributed by Peter R. Grant, September 11, 2018 (sent for review August 8, 2018; reviewed by Darren Irwin and Carel ten Cate) Global biodiversity is being degraded at an unprecedented rate, as shown by the numerous examples of introgressive hybridiza- so it is important to preserve the potential for future specia- tion between recently formed species (reviewed in refs. 10–13). tion. Providing for the future requires understanding speciation Important questions that need to be addressed are how the as a contemporary ecological process. Phylogenetically young barrier is constructed, how it evolved, why it occasionally leaks, adaptive radiations are a good choice for detailed study because and how gene exchange affects the evolution of the respective diversification is ongoing. A key question is how incipient species populations (14). Paradoxically, the breakdown of reproductive become reproductively isolated from each other. Barriers to gene isolation may be especially informative in answering questions exchange have been investigated experimentally in the laboratory about how it was established by exposing candidate traits that and in the field, but little information exists from the quantitative constitute the normally effective barrier to interbreeding (15– study of mating patterns in nature. Although the degree to which 17). Further insights can then be gained by conducting experi- genetic variation underlying mate-preference learning is un- ments on the genetic and experiential basis of mate choice and known, we provide evidence that two species of Darwin’s finches preferences of closely related species (16, 18–22).
    [Show full text]
  • Ecological Genetics – HS18 V0.2 Gleb Ebert October 13, 2018
    Ecological Genetics – HS18 v0.2 Gleb Ebert October 13, 2018 Vorwort This document aims to summarize the lecture Ecological Genetics as it was taught in the autumn semester of 2018. Unfortunately I can’t guarantee that it is complete and free of errors. You can contact me under [email protected] if you have any suggestions for improvement. The newest version of this summary can always be found here: https://n.ethz.ch/~glebert/ Contents 1 Introduction 2 2 Species 2 3 Molecular Markers 3 4 Sampling 4 1 1 Introduction 2.1 Species concepts • Morphological / typological species concept: focus on “Nothing in biology makes sense except in the light of similar morphology evolution” • Biological species concept: group of potentially or — Theodosius Dobzhansky actually interbreeding populations which are repro- ductively isolated from other such groups In 1971 Ford wrote that ecological genetics deal with the • Phylogenetic species concept: focuses on monophyletic adjustments and adaptations of wild populations to their lineages environment. According to Conner and Hartl (2004) eco- logical genetics is the study of the process of phenotypic 2.2 Operational Taxonomic Unit evolution occurring in present-day natural populations and is concerned with the genetics of ecologically important An OTU is a group of organisms that is treated as a distinct traits, that is, those traits related to fitness. evolutionary unit for the purposes of research underway. Phenotypic evolution is the change in the mean or vari- They are often applied when one or several species con- ance of a trait across generations due to changes in allele cepts fail.
    [Show full text]
  • The Ecological Genetics of Floral Traits
    Heredity (2006) 97, 86–87 & 2006 Nature Publishing Group All rights reserved 0018-067X/06 $30.00 www.nature.com/hdy NEWS AND COMMENTARY ...............................................................Adaptive evolution zygomorphs does not represent a long- term constraint on angiosperm evolu- The ecological genetics of floral tion. Studies that focus on lineages with both actinomorphic and zygomorphic traits species could be useful in resolving this contradiction between patterns of CM Caruso genetic variation within species and ........................................................... speciation within clades. Heredity (2006) 97, 86–87. doi:10.1038/sj.hdy.6800853; published online 31 May 2006 Finally, mean rg between flower size and number was not significantly dif- ferent from zero, which does not sup- loral traits have fascinated evolu- because evolution in response to natural port the hypothesis that the evolution of tionary biologists since Darwin selection is slower for species with floral displays is genetically constrained F published ‘The various contri- lower h2, self-pollinating angiosperm by a trade-off between the size and vances by which orchids are fertilized species will not be able to respond to number of flowers produced by a plant. by insects’ in 1862. Because flowers are novel selection pressures and conse- This is a significant result because the remarkably diverse and important for quently may have elevated extinction inverse relationship between flower size sexual reproduction in plants, floral rates. The evolution of selfing species and number is the type of resource traits are excellent subjects for studies from outcrossing ancestors is one of the allocation trade-off that underlies much of adaptive microevolution. In addition, most common evolutionary transitions of life history and sex allocation theory floral traits are unique among plant in angiosperms and, as such, Stebbins’ and is an assumption of many theore- traits because they can directly influ- hypothesis has dominated the field of tical models of floral evolution.
    [Show full text]
  • Biology B242: Evolutionary and Ecological Genetics Exam 2000
    BIOLOGY B242: EVOLUTIONARY AND ECOLOGICAL GENETICS EXAM 2000 Answer ONE question from section A, TWO questions from section B, and ALL OF section C (overleaf). Each section carries 1/3 of the marks on the paper. SECTION A. Answer ONE of questions 1-3. 1. Consider, using specific cases, whether evolutionary biologists in the year 2000 need to invoke different genetic processes to account for micro- and macro-evolution? 2. Are the effects of mutation on fitness important in evolution? Support your argument with suitable examples. 3. “Every species has come into existence coincident both in space and time with a pre- existing closely allied species” (Wallace 1855). Discuss this statement in the light of modern theories of spatial evolution. SECTION B. Answer TWO of questions 4-8. 4. What are the relative merits of the phylogenetic and cladistic approaches to resolving the classification of species? Assess the assumptions of each method in your answer. 5. How does genetic drift interact with selection in (a) chromosomal evolution OR (b) survival of endangered populations? 6. Is artificial selection a useful tool for an evolutionary biologist? Give some examples of its use to illustrate your response. 7. What are secondary sexual characteristics? What best explains them? 8. What use is linkage disequilibrium in modern evolutionary genetics? Remember to answer Section C overleaf! TURN OVER SECTION C. Attempt ALL parts of question 9. 9. Dobzhansky studied the frequency of inversions “Standard” and “Arrowhead” in two mountain peak populations of Drosophila pseudoobscura in California 50 km apart: Inversion Arrowhead Arrowhead/Standard Standard Genotype Homozygotes Heterozygotes Homozygotes Kingston Peak 52 39 12 Charleston Peak 102 21 5 a) Estimate the frequencies of Standard and Arrowhead in each population.
    [Show full text]
  • The Evolutionary Genetics of Adaptation: a Simulation Study
    Genet. Res., Camb.(1999), 74, pp. 207–214. With 4 figures. Printed in the United Kingdom # 1999 Cambridge University Press 207 The evolutionary genetics of adaptation: a simulation study H.ALLEN ORR* Department of Biology, Uniersity of Rochester, Rochester, NY 14627, USA (Receied 30 March 1999 and in reised form 1 July 1999) Summary It is now clear that the genetic basis of adaptation does not resemble that assumed by the infinitesimal model. Instead, adaptation often involves a modest number of factors of large effect and a greater number of factors of smaller effect. After reviewing relevant experimental studies, I consider recent theoretical attempts to predict the genetic architecture of adaptation from first principles. In particular, I review the history of work on Fisher’s geometric model of adaptation, including recent studies which suggest that adaptation should be characterized by exponential distributions of gene effects. I also present the results of new simulation studies that test the robustness of this finding. I explore the effects of changes in the distribution of mutational effects (absolute versus relative) as well as in the nature of the character studied (total phenotypic effect versus single characters). The results show that adaptation towards a fixed optimum is generally characterized by an exponential effects trend. The situation to which these studies point is not one of a More recent work has confirmed these classic large number of genes all with more or less equal effect. It findings from ecological genetics. ffrench-Constant seems, rather, that a small number of genes with large effects (1994), for instance, has shown that insecticide are responsible for most of the response, the remainder of the response being due to a larger number of loci with small (cyclodiene) resistance in the wild among at least three effects.
    [Show full text]
  • Recent Trends in Research on the Genetic Diversity of Plants: Implications for Conservation
    diversity Article Recent Trends in Research on the Genetic Diversity of Plants: Implications for Conservation Yasmin G. S. Carvalho 1, Luciana C. Vitorino 1,* , Ueric J. B. de Souza 2,3 and Layara A. Bessa 1 1 Laboratory of Plant Mineral Nutrition, Instituto Federal Goiano campus Rio Verde, Rodovia Sul Goiana, km 01, Zona Rural, Rio Verde, GO 75901-970, Brazil; [email protected] (Y.G.S.C.); [email protected] (L.A.B.) 2 Laboratory of Genetics and Biodiversity, Instituto de Ciências Biológicas, Universidade Federal de Goiás—UFG, Avenida Esperança s/n, campus Samambaia, Goiânia, GO 74690-900, Brazil; [email protected] 3 National Institute for Science and Technology in Ecology, Evolution and Conservation of Biodiversity, Universidade Federal de Goiás, Goiânia, GO 74690-900, Brazil * Correspondence: [email protected] Received: 21 March 2019; Accepted: 16 April 2019; Published: 18 April 2019 Abstract: Genetic diversity and its distribution, both within and between populations, may be determined by micro-evolutionary processes, such as the demographic history of populations, natural selection, and gene flow. In plants, indices of genetic diversity (e.g., k, h and π) and structure (e.g., FST) are typically inferred from sequences of chloroplast markers. Given the recent advances and popularization of molecular techniques for research in population genetics, phylogenetics, phylogeography, and ecology, we adopted a scientometric approach to compile evidence on the recent trends in the use of cpDNA sequences as markers for the analysis of genetic diversity in botanical studies, over the years. We also used phylogenetic modeling to assess the relative contribution of relatedness or ecological and reproductive characters to the genetic diversity of plants.
    [Show full text]
  • Linking Ecological Divergence and Reproductive Isolation: a Tale of Two Killifish
    LINKING ECOLOGICAL DIVERGENCE AND REPRODUCTIVE ISOLATION: A TALE OF TWO KILLIFISH BY EMMA LISBETH CORASH BERDAN DISSERTATION Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biology with a concentration in Ecology, Ethology, and Evolution in the Graduate College of the University of Illinois at Urbana-Champaign, 2012 Urbana, Illinois Doctoral Committee: Associate Professor Rebecca C. Fuller, Chair and Director of Research Professor Stewart Berlocher Associate Professor Chi-Hing Christina Cheng Assistant Professor Alison M. Bell ABSTRACT Gene flow and recombination directly oppose genetic differentiation and speciation because they homogenize allele combinations that are unique to each population/species (Felsenstein 1981; Rieseberg 2001; Ortiz-Barrientos, Reiland et al. 2002; Butlin 2005). Under divergence with gene flow, either very strong selection or some other mechanism that reduces recombination rates is needed to maintain different allelic combinations. Decreased recombination is especially important in cases of ecological speciation with gene flow. A decade of work in evolutionary biology indicates that divergent natural selection in different habitats is usually involved in speciation (i.e. ecological speciation). While ecological selection alone can promote speciation (Schluter 2001; Rundle and Nosil 2005; Schluter and Conte 2009), a variety of species contain populations that are adapted to different habitats and yet have not undergone speciation (Hendry 2009; Nosil, Harmon et al. 2009). These conflicting outcomes suggest that ecological selection need not always lead to the evolution of reproductive isolating barriers (RIBs). When the genes under ecological selection also confer reproductive isolation, ecological speciation occurs readily (Boughman 2001; Kirkpatrick and Ravigne 2002; Gavrilets 2004).
    [Show full text]
  • The Rate of Spontaneous Mutation for Life-History Traits in Caenorhabditis Elegans
    Copyright 1999 by the Genetics Society of America The Rate of Spontaneous Mutation for Life-History Traits in Caenorhabditis elegans Larissa L. Vassilieva and Michael Lynch Department of Biology, University of Oregon, Eugene, Oregon 97403 Manuscript received September 1, 1997 Accepted for publication September 18, 1998 ABSTRACT Spontaneous mutations were accumulated in 100 replicate lines of Caenorhabditis elegans over a period of z50 generations. Periodic assays of these lines and comparison to a frozen control suggest that the deleterious mutation rate for typical life-history characters in this species is at least 0.05 per diploid genome per generation, with the average mutational effect on the order of 14% or less in the homozygous state and the average mutational heritability z0.0034. While the average mutation rate per character and the average mutational heritability for this species are somewhat lower than previous estimates for Drosophila, these differences can be reconciled to a large extent when the biological differences between these species are taken into consideration. RACTICAL interest in the properties of new muta- relevance to the adaptive evolutionary process is far Ptions is motivated by two issues. First, the viability of from clear. Although the data are taxonomically limited, species con®ned to a temporally changing environment the existing evidence for Drosophila and Escherichia coli ultimately depends on the rate at which mutation can imply that the vast majority of mutations have deleteri- generate new variation that can be assimilated into the ous effects on ®tness (Simmons and Crow 1977; Crow adaptive evolutionary process (Lynch and Lande 1993; and Simmons 1983; Crow 1993; Houle et al.
    [Show full text]
  • Evolutionary and Ecological Genetics of Medicago Truncatula
    Medicago truncatula handbook version November 2006 Evolutionary and Ecological Genetics of Medicago truncatula Thomas Bataillon Bioinformatics Research Center & Department of Genetics and Ecology, Aarhus University, Hoegh-Guldbergs Gade 10, Building 1090, DK-8000 Aarhus C. Denmark [email protected] http://www.daimi.au.dk/~tbata Joelle Ronfort UMR 1097 DGPC, INRA domaine de Melgueil, F-34130 Maugio, France. [email protected] Table of contents 1. Introduction 2. The mating system of Medicago truncatula 3. Distribution of genetic variation in Medicago truncatula 3.1 Within population polymorphism 3.2 Population structure in Medicago truncatula 4. Variation in quantitative traits: Is there ecotypic differentiation in Medicago truncatula? 5 Perspectives: towards the ecological and evolutionary genomics of Medicago truncatula References Figures Abstract This chapter synthesizes our current knowledge on the ecological genetics of the model legume Medicago truncatula. After a short introduction to the life cycle of the species, we describe the mating system of M truncatula and how selfing rates in nature can be inferred both by progeny testing and population surveys. We then review what is currently known on the distribution of genetic diversity within and among populations focusing first on the diversity that can be assessed using a priori neutral makers (allozyme and SSR). We then consider genetic variation for quantitative traits and discuss whether Medicago truncatula exhibits a so called “ecotypic” differentiation. Last we discuss how genomic tools and the availability of sequence information may help shed additional light on the evolutionary forces behind evolution and adaptation in Medicago truncatula. Evolutionary and Ecological Genetics of Medicago truncatula Page 1 of 13 Medicago truncatula handbook version November 2006 1 Introduction Medicago truncatula GAERTN is an annual species which is strongly selfing in nature.
    [Show full text]