Lecture 13: Introduction to Population Genetics
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Population Size and the Rate of Evolution
Review Population size and the rate of evolution 1,2 1 3 Robert Lanfear , Hanna Kokko , and Adam Eyre-Walker 1 Ecology Evolution and Genetics, Research School of Biology, Australian National University, Canberra, ACT, Australia 2 National Evolutionary Synthesis Center, Durham, NC, USA 3 School of Life Sciences, University of Sussex, Brighton, UK Does evolution proceed faster in larger or smaller popu- mutations occur and the chance that each mutation lations? The relationship between effective population spreads to fixation. size (Ne) and the rate of evolution has consequences for The purpose of this review is to synthesize theoretical our ability to understand and interpret genomic varia- and empirical knowledge of the relationship between tion, and is central to many aspects of evolution and effective population size (Ne, Box 1) and the substitution ecology. Many factors affect the relationship between Ne rate, which we term the Ne–rate relationship (NeRR). A and the rate of evolution, and recent theoretical and positive NeRR implies faster evolution in larger popula- empirical studies have shown some surprising and tions relative to smaller ones, and a negative NeRR implies sometimes counterintuitive results. Some mechanisms the opposite (Figure 1A,B). Although Ne has long been tend to make the relationship positive, others negative, known to be one of the most important factors determining and they can act simultaneously. The relationship also the substitution rate [5–8], several novel predictions and depends on whether one is interested in the rate of observations have emerged in recent years, causing some neutral, adaptive, or deleterious evolution. Here, we reassessment of earlier theory and highlighting some gaps synthesize theoretical and empirical approaches to un- in our understanding. -
Transformations of Lamarckism Vienna Series in Theoretical Biology Gerd B
Transformations of Lamarckism Vienna Series in Theoretical Biology Gerd B. M ü ller, G ü nter P. Wagner, and Werner Callebaut, editors The Evolution of Cognition , edited by Cecilia Heyes and Ludwig Huber, 2000 Origination of Organismal Form: Beyond the Gene in Development and Evolutionary Biology , edited by Gerd B. M ü ller and Stuart A. Newman, 2003 Environment, Development, and Evolution: Toward a Synthesis , edited by Brian K. Hall, Roy D. Pearson, and Gerd B. M ü ller, 2004 Evolution of Communication Systems: A Comparative Approach , edited by D. Kimbrough Oller and Ulrike Griebel, 2004 Modularity: Understanding the Development and Evolution of Natural Complex Systems , edited by Werner Callebaut and Diego Rasskin-Gutman, 2005 Compositional Evolution: The Impact of Sex, Symbiosis, and Modularity on the Gradualist Framework of Evolution , by Richard A. Watson, 2006 Biological Emergences: Evolution by Natural Experiment , by Robert G. B. Reid, 2007 Modeling Biology: Structure, Behaviors, Evolution , edited by Manfred D. Laubichler and Gerd B. M ü ller, 2007 Evolution of Communicative Flexibility: Complexity, Creativity, and Adaptability in Human and Animal Communication , edited by Kimbrough D. Oller and Ulrike Griebel, 2008 Functions in Biological and Artifi cial Worlds: Comparative Philosophical Perspectives , edited by Ulrich Krohs and Peter Kroes, 2009 Cognitive Biology: Evolutionary and Developmental Perspectives on Mind, Brain, and Behavior , edited by Luca Tommasi, Mary A. Peterson, and Lynn Nadel, 2009 Innovation in Cultural Systems: Contributions from Evolutionary Anthropology , edited by Michael J. O ’ Brien and Stephen J. Shennan, 2010 The Major Transitions in Evolution Revisited , edited by Brett Calcott and Kim Sterelny, 2011 Transformations of Lamarckism: From Subtle Fluids to Molecular Biology , edited by Snait B. -
Allele Frequency–Based and Polymorphism-Versus
View metadata, citation and similar papers at core.ac.uk brought to you by CORE Allele Frequency–Based and Polymorphism-Versus- provided by PubMed Central Divergence Indices of Balancing Selection in a New Filtered Set of Polymorphic Genes in Plasmodium falciparum Lynette Isabella Ochola,1 Kevin K. A. Tetteh,2 Lindsay B. Stewart,2 Victor Riitho,1 Kevin Marsh,1 and David J. Conway*,2 1Kenya Medical Research Institute, Centre for Geographic Medicine Research Coast, Kilifi, Kenya 2Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom *Corresponding author: E-mail: [email protected], [email protected]. Associate editor: John H. McDonald Research article Abstract Signatures of balancing selection operating on specific gene loci in endemic pathogens can identify candidate targets of naturally acquired immunity. In malaria parasites, several leading vaccine candidates convincingly show such signatures when subjected to several tests of neutrality, but the discovery of new targets affected by selection to a similar extent has been slow. A small minority of all genes are under such selection, as indicated by a recent study of 26 Plasmodium falciparum merozoite- stage genes that were not previously prioritized as vaccine candidates, of which only one (locus PF10_0348) showed a strong signature. Therefore, to focus discovery efforts on genes that are polymorphic, we scanned all available shotgun genome sequence data from laboratory lines of P. falciparum and chose six loci with more than five single nucleotide polymorphisms per kilobase (including PF10_0348) for in-depth frequency–based analyses in a Kenyan population (allele sample sizes .50 for each locus) and comparison of Hudson–Kreitman–Aguade (HKA) ratios of population diversity (p) to interspecific divergence (K) from the chimpanzee parasite Plasmodium reichenowi. -
IN EVOLUTION JACK LESTER KING UNIVERSITY of CALIFORNIA, SANTA BARBARA This Paper Is Dedicated to Retiring University of California Professors Curt Stern and Everett R
THE ROLE OF MUTATION IN EVOLUTION JACK LESTER KING UNIVERSITY OF CALIFORNIA, SANTA BARBARA This paper is dedicated to retiring University of California Professors Curt Stern and Everett R. Dempster. 1. Introduction Eleven decades of thought and work by Darwinian and neo-Darwinian scientists have produced a sophisticated and detailed structure of evolutionary ,theory and observations. In recent years, new techniques in molecular biology have led to new observations that appear to challenge some of the basic theorems of classical evolutionary theory, precipitating the current crisis in evolutionary thought. Building on morphological and paleontological observations, genetic experimentation, logical arguments, and upon mathematical models requiring simplifying assumptions, neo-Darwinian theorists have been able to make some remarkable predictions, some of which, unfortunately, have proven to be inaccurate. Well-known examples are the prediction that most genes in natural populations must be monomorphic [34], and the calculation that a species could evolve at a maximum rate of the order of one allele substitution per 300 genera- tions [13]. It is now known that a large proportion of gene loci are polymorphic in most species [28], and that evolutionary genetic substitutions occur in the human line, for instance, at a rate of about 50 nucleotide changes per generation [20], [24], [25], [26]. The puzzling observation [21], [40], [46], that homologous proteins in different species evolve at nearly constant rates is very difficult to account for with classical evolutionary theory, and at the very least gives a solid indication that there are qualitative differences between the ways molecules evolve and the ways morphological structures evolve. -
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. -
Intro Forensic Stats
Popstats Unplugged 14th International Symposium on Human Identification John V. Planz, Ph.D. UNT Health Science Center at Fort Worth Forensic Statistics From the ground up… Why so much attention to statistics? Exclusions don’t require numbers Matches do require statistics Problem of verbal expression of numbers Transfer evidence Laboratory result 1. Non-match - exclusion 2. Inconclusive- no decision 3. Match - estimate frequency Statistical Analysis Focus on the question being asked… About “Q” sample “K” matches “Q” Who else could match “Q" partial profile, mixtures Match – estimate frequency of: Match to forensic evidence NOT suspect DNA profile Who is in suspect population? So, what are we really after? Quantitative statement that expresses the rarity of the DNA profile Estimate genotype frequency 1. Frequency at each locus Hardy-Weinberg Equilibrium 2. Frequency across all loci Linkage Equilibrium Terminology Genetic marker variant = allele DNA profile = genotype Database = table that provides frequency of alleles in a population Population = some assemblage of individuals based on some criteria for inclusion Where Do We Get These Numbers? 1 in 1,000,000 1 in 110,000,000 POPULATION DATA and Statistics DNA databases are needed for placing statistical weight on DNA profiles vWA data (N=129) 14 15 16 17 18 19 20 freq 14 9 75 15 3 0 6 16 19 1 1 46 17 23 1 14 9 72 18 6 0 3 10 4 31 19 6 1 7 3 2 2 23 20 0 0 0 3 2 0 0 5 258 Because data are not available for every genotype possible, We use allele frequencies instead of genotype frequencies to estimate rarity. -
Working at the Interface of Phylogenetics and Population
Molecular Ecology (2007) 16, 839–851 doi: 10.1111/j.1365-294X.2007.03192.x WorkingBlackwell Publishing Ltd at the interface of phylogenetics and population genetics: a biogeographical analysis of Triaenops spp. (Chiroptera: Hipposideridae) A. L. RUSSELL,* J. RANIVO,†‡ E. P. PALKOVACS,* S. M. GOODMAN‡§ and A. D. YODER¶ *Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520, USA, †Département de Biologie Animale, Université d’Antananarivo, Antananarivo, BP 106, Madagascar, ‡Ecology Training Program, World Wildlife Fund, Antananarivo, BP 906 Madagascar, §The Field Museum of Natural History, Division of Mammals, 1400 South Lake Shore Drive, Chicago, IL 60605, USA, ¶Department of Ecology and Evolutionary Biology, PO Box 90338, Duke University, Durham, NC 27708, USA Abstract New applications of genetic data to questions of historical biogeography have revolutionized our understanding of how organisms have come to occupy their present distributions. Phylogenetic methods in combination with divergence time estimation can reveal biogeo- graphical centres of origin, differentiate between hypotheses of vicariance and dispersal, and reveal the directionality of dispersal events. Despite their power, however, phylo- genetic methods can sometimes yield patterns that are compatible with multiple, equally well-supported biogeographical hypotheses. In such cases, additional approaches must be integrated to differentiate among conflicting dispersal hypotheses. Here, we use a synthetic approach that draws upon the analytical strengths of coalescent and population genetic methods to augment phylogenetic analyses in order to assess the biogeographical history of Madagascar’s Triaenops bats (Chiroptera: Hipposideridae). Phylogenetic analyses of mitochondrial DNA sequence data for Malagasy and east African Triaenops reveal a pattern that equally supports two competing hypotheses. -
What Is a Recessive Allele?
What Is a Recessive Allele? WernerG. Heim ONE of the commonlymisunderstood and misin- are termedthe dominant[dominirende], and those terpreted concepts in elementary genetics is that which becomelatent in the processrecessive [reces- sive]. The expression"recessive" has been chosen of dominance and recessiveness of alleles. Many becausethe charactersthereby designated withdraw students in introductory courses perceive the idea or entirelydisappear in the hybrids,but nevertheless that the dominant form of a gene is somehow stron- reappear unchanged in their progeny ... (Mendel ger than the recessive form and, when they are 1950,p. 8) together in a heterozygote, the dominant allele sup- Two important concepts are presented here: (1) presses the action of the recessive one. This belief is Statements about dominance and recessiveness are Downloaded from http://online.ucpress.edu/abt/article-pdf/53/2/94/44793/4449229.pdf by guest on 27 September 2021 not only incorrectbut it can lead to a whole series of statements about the appearanceof characters,about further errors. Students, for example, often errone- what is seen or can be detected, not about the ously conclude that because the dominant allele is the underlying genetic situation; (2) The relationship stronger, it therefore ought to become more common between two alleles of a gene falls on a continuous in the course of evolution. scale from one of complete dominance and recessive- There are other common misconceptions, among ness to a complete lack thereof. In the latter case, the them that: expression of both alleles is seen in either of two ways 1) Dominance operates at the genotypic level. -
Muller's Ratchet As a Mechanism of Frailty and Multimorbidity
bioRxivMuller’s preprint ratchetdoi: https://doi.org/10.1101/439877 and frailty ; this version posted[Type Octoberhere] 10, 2018. The copyright holder Govindarajufor this preprint and (which Innan was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 Muller’s ratchet as a mechanism of frailty and multimorbidity 2 3 Diddahally R. Govindarajua,b,1, 2, and Hideki Innanc,1,2 4 5 aDepartment of Human Evolutionary Biology, Harvard University, Cambridge, MA 02138; 6 and bThe Institute of Aging Research, Albert Einstein College of Medicine, Bronx, 7 NY 1046, and cGraduate University for Advanced Studies, Hayama, Kanagawa, 8 240-0193, Japan 9 10 11 12 Authors contributions: D.R.G., H.I designed study, performed research, contributed new 13 analytical tools, analyzed data and wrote the paper 14 15 The authors declare no conflict of interest 16 1D.R.G., and H.I. contributed equally to this work and listed alphabetically 17 2 Correspondence: Email: [email protected]; [email protected] 18 19 Senescence | mutation accumulation | asexual reproduction | somatic cell-lineages| 20 organs and organ systems |Muller’s ratchet | fitness decay| frailty and multimorbidity 21 22 23 24 25 26 27 28 29 30 31 32 1 bioRxivMuller’s preprint ratchetdoi: https://doi.org/10.1101/439877 and frailty ; this version posted[Type Octoberhere] 10, 2018. The copyright holder Govindarajufor this preprint and (which Innan was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 33 Mutation accumulation has been proposed as a cause of senescence. -
Basic Genetic Terms for Teachers
Student Name: Date: Class Period: Page | 1 Basic Genetic Terms Use the available reference resources to complete the table below. After finding out the definition of each word, rewrite the definition using your own words (middle column), and provide an example of how you may use the word (right column). Genetic Terms Definition in your own words An example Allele Different forms of a gene, which produce Different alleles produce different hair colors—brown, variations in a genetically inherited trait. blond, red, black, etc. Genes Genes are parts of DNA and carry hereditary Genes contain blue‐print for each individual for her or information passed from parents to children. his specific traits. Dominant version (allele) of a gene shows its Dominant When a child inherits dominant brown‐hair gene form specific trait even if only one parent passed (allele) from dad, the child will have brown hair. the gene to the child. When a child inherits recessive blue‐eye gene form Recessive Recessive gene shows its specific trait when (allele) from both mom and dad, the child will have blue both parents pass the gene to the child. eyes. Homozygous Two of the same form of a gene—one from Inheriting the same blue eye gene form from both mom and the other from dad. parents result in a homozygous gene. Heterozygous Two different forms of a gene—one from Inheriting different eye color gene forms from mom mom and the other from dad are different. and dad result in a heterozygous gene. Genotype Internal heredity information that contain Blue eye and brown eye have different genotypes—one genetic code. -
Lesson Plan Mendelian Inheritance
Dolan DNA Learning Center Mendelian Inheritance __________________________________________________________________________________________ Overview • Computer with internet access This 90 minute lesson (two class periods of 45 minutes) is an introduction to Mendel’s Laws of Inheritance for students in Lesson Structure grades 5 through 8. By studying inherited traits in humans such as tasting PTC paper and inherited traits in plants such as Pre-lab (45 minutes) – Day 1 maize, we can understand how traits are passed down through Teacher Prep generations. A discussion of dominant and recessive traits in humans will encourage students to further explore their • Become familiar with Lab Center inheritance as well as their family inheritance. http://www.dnalc.org/labcenter/mendeliangenetics/m endeliangenetics_d.html Learning Outcomes • Print and copy Background Reading from the Students will be able to: Student Lab Notebook on the Lab center. • discuss the contributions of Gregor Mendel and his • Print and copy Student Pre-lab Worksheets from experiments with the garden pea. the Student Lab Notebook on the Lab center. • review the structure of DNA and chromosomes. • Cut paper strips for Sentence Strips activity. • compare a dominant trait to a recessive trait. • Make sure computers with Internet access are • compare a homozygous trait to a heterozygous trait. available. • identify traits in themselves that are either dominant or recessive. Before class • use maize as a model organism to study Mendelian Students will receive the background reading to read for inheritance. homework the night before starting lab. They will write 2 to 3 • demonstrate Mendel’s Law of Dominance and Law questions they have about the background information. -
Basic Genetic Concepts & Terms
Basic Genetic Concepts & Terms 1 Genetics: what is it? t• Wha is genetics? – “Genetics is the study of heredity, the process in which a parent passes certain genes onto their children.” (http://www.nlm.nih.gov/medlineplus/ency/article/002048. htm) t• Wha does that mean? – Children inherit their biological parents’ genes that express specific traits, such as some physical characteristics, natural talents, and genetic disorders. 2 Word Match Activity Match the genetic terms to their corresponding parts of the illustration. • base pair • cell • chromosome • DNA (Deoxyribonucleic Acid) • double helix* • genes • nucleus Illustration Source: Talking Glossary of Genetic Terms http://www.genome.gov/ glossary/ 3 Word Match Activity • base pair • cell • chromosome • DNA (Deoxyribonucleic Acid) • double helix* • genes • nucleus Illustration Source: Talking Glossary of Genetic Terms http://www.genome.gov/ glossary/ 4 Genetic Concepts • H describes how some traits are passed from parents to their children. • The traits are expressed by g , which are small sections of DNA that are coded for specific traits. • Genes are found on ch . • Humans have two sets of (hint: a number) chromosomes—one set from each parent. 5 Genetic Concepts • Heredity describes how some traits are passed from parents to their children. • The traits are expressed by genes, which are small sections of DNA that are coded for specific traits. • Genes are found on chromosomes. • Humans have two sets of 23 chromosomes— one set from each parent. 6 Genetic Terms Use library resources to define the following words and write their definitions using your own words. – allele: – genes: – dominant : – recessive: – homozygous: – heterozygous: – genotype: – phenotype: – Mendelian Inheritance: 7 Mendelian Inheritance • The inherited traits are determined by genes that are passed from parents to children.