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Allelic Frequency Definition Biology: A Comprehensive Guide
Author: Dr. Evelyn Reed, PhD, Professor of Population Genetics, University of California, Berkeley. (Dr. Reed has over 20 years of experience in population genetics research, with a focus on allele frequency dynamics and their implications for conservation biology and human health.)
Publisher: Nature Education – a leading provider of high-quality scientific education resources, renowned for its peer-reviewed content and commitment to accuracy in biological sciences.
Editor: Dr. Michael Jones, PhD, Senior Editor, Nature Education (Dr. Jones has extensive experience editing scientific publications and possesses a strong background in evolutionary biology.)
Summary: This guide provides a comprehensive understanding of allelic frequency definition biology, explaining its calculation, significance in population genetics, factors influencing its changes, and common pitfalls in its interpretation. It explores various applications of allelic frequency data in fields like conservation, medicine, and forensic science, highlighting best practices and potential limitations.
Keywords: allelic frequency definition biology, allele frequency, population genetics, Hardy-Weinberg equilibrium, genetic drift, gene flow, mutation, natural selection, genetic diversity, conservation biology, forensic science, medical genetics.
What is Allelic Frequency Definition Biology?
The allelic frequency definition biology refers to the relative frequency of a particular allele (variant form of a gene) within a population. It's expressed as a proportion or percentage of all alleles for that specific gene present in the population. Understanding allelic frequency is fundamental to population genetics, providing insights into the genetic makeup of populations and how it changes over time. This understanding of allelic frequency definition biology is crucial in various applications across many fields.
Calculating Allelic Frequency
Calculating allelic frequency involves determining the number of times a specific allele appears within a gene pool and dividing it by the total number of all alleles for that gene in the population. For instance, consider a gene with two alleles, A and a. If a population of 100 individuals has 60 A alleles and 40 a alleles, the allelic frequency of A is 60/200 = 0.3 (or 30%), and the allelic frequency of a is 40/200 = 0.2 (or 20%). The sum of all allelic frequencies for a given gene always equals 1 (or 100%).
Factors Affecting Allelic Frequency
Several evolutionary mechanisms influence allelic frequency definition biology:
Mutation: New alleles arise through mutations, altering allelic frequencies. While individual mutations may have a small effect, accumulation over time can significantly change the genetic makeup of a population.
Genetic Drift: Random fluctuations in allele frequencies, particularly pronounced in small populations. Genetic drift can lead to the loss of alleles or fixation (reaching 100% frequency) of certain alleles, impacting genetic diversity.
Gene Flow: The movement of alleles between populations through migration. Gene flow can introduce new alleles into a population, homogenizing allele frequencies across different populations or leading to divergence depending on the influx of genetic material.
Natural Selection: The differential survival and reproduction of individuals based on their genotypes. Alleles conferring advantageous traits tend to increase in frequency, while those associated with disadvantageous traits decrease.
The Hardy-Weinberg Equilibrium and Allelic Frequency
The Hardy-Weinberg principle provides a baseline model for understanding allelic frequencies in populations. It states that allele and genotype frequencies will remain constant from generation to generation in the absence of evolutionary influences. The principle assumes:
No mutation
Random mating
No gene flow
Infinite population size (no genetic drift)
No natural selection
Deviations from the Hardy-Weinberg equilibrium suggest that evolutionary forces are acting upon the population, thereby altering allelic frequencies. Analyzing these deviations helps researchers identify and investigate the driving forces of evolution.
Applications of Allelic Frequency Data
The understanding of allelic frequency definition biology has crucial applications in various fields:
Conservation Biology: Monitoring allelic frequencies helps assess the genetic diversity of endangered species, aiding conservation efforts. Low allelic frequency indicates reduced genetic variation, increasing the species’ vulnerability to environmental changes and diseases.
Medical Genetics: Analyzing allelic frequencies of disease-causing alleles helps understand disease prevalence and susceptibility within populations. This information is valuable for developing targeted preventative measures and therapies.
Forensic Science: Allelic frequencies of specific genetic markers are used in DNA fingerprinting to identify individuals and assess the probability of matches.
Common Pitfalls in Interpreting Allelic Frequency Data
Several factors can complicate the interpretation of allelic frequency data:
Sampling Bias: Non-representative samples can lead to inaccurate estimations of allelic frequencies. Careful sampling strategies are necessary to ensure accurate representation of the population.
Population Structure: Subpopulations within a larger population may have different allelic frequencies. Ignoring population structure can lead to misleading conclusions about the overall allelic frequency.
Linkage Disequilibrium: Non-random association between alleles at different loci can affect the interpretation of allelic frequencies. Accounting for linkage disequilibrium is critical for accurate analysis.
Best Practices for Studying Allelic Frequency
To ensure reliable results when studying allelic frequency definition biology, researchers should follow these best practices:
Employ rigorous sampling methods to minimize bias.
Consider population structure and account for it in analysis.
Use appropriate statistical methods to analyze the data.
Validate findings through replication and comparison with other studies.
Conclusion
Understanding the allelic frequency definition biology is critical for comprehending evolutionary processes and their implications across diverse biological systems. By carefully considering the factors influencing allelic frequencies and employing appropriate analytical techniques, researchers can gain valuable insights into population genetics, genetic diversity, and the evolutionary trajectory of species. The applications of this knowledge are far-reaching, impacting fields like conservation, medicine, and forensics, highlighting the fundamental importance of allelic frequency in biological research.
FAQs
1. What is the difference between allelic frequency and genotypic frequency? Allelic frequency refers to the proportion of a specific allele in a population, while genotypic frequency refers to the proportion of a specific genotype (combination of alleles).
2. How does mutation affect allelic frequency? Mutation introduces new alleles into a population, slowly changing the allelic frequencies over time.
3. Can allelic frequency be used to predict future genetic diversity? While not a perfect predictor, allelic frequency data, combined with other factors (e.g., population size, environmental pressures), can provide insights into potential changes in genetic diversity.
4. How is allelic frequency related to genetic drift? Genetic drift causes random fluctuations in allelic frequencies, especially in small populations.
5. What is the role of gene flow in allelic frequency? Gene flow introduces or removes alleles from populations, thus altering allelic frequencies.
6. How does natural selection affect allelic frequency? Natural selection favors alleles that enhance survival and reproduction, increasing their frequency in the population.
7. What is the significance of Hardy-Weinberg equilibrium in understanding allelic frequencies? It provides a null hypothesis against which to compare observed allelic frequencies, revealing the action of evolutionary forces.
8. How is allelic frequency used in forensic science? Allelic frequencies of specific DNA markers are used to assess the probability of a match between DNA samples.
9. What are some limitations of using allelic frequency data? Sampling bias, population structure, and linkage disequilibrium can complicate the interpretation of allelic frequency data.
Related Articles:
1. Hardy-Weinberg Equilibrium and its Applications: A detailed explanation of the Hardy-Weinberg principle, its assumptions, and its use in population genetic analysis.
2. Genetic Drift and its Impact on Allele Frequencies: An in-depth exploration of genetic drift, its mechanisms, and its consequences for genetic diversity.
3. Gene Flow and its Role in Shaping Population Genetics: A discussion of gene flow and its effects on allelic frequencies and population structure.
4. Natural Selection and Allelic Frequency Change: An examination of how natural selection alters allelic frequencies and drives adaptation.
5. Mutation and its Contribution to Genetic Variation: A comprehensive review of different mutation types and their influence on allelic frequencies.
6. Conservation Genetics and Allelic Frequency Monitoring: The role of allelic frequency monitoring in conservation efforts to maintain genetic diversity in endangered species.
7. Medical Genetics and Allelic Frequency Analysis of Disease Genes: The use of allelic frequency data to understand disease prevalence and predisposition.
8. Forensic DNA Analysis and Allelic Frequency Databases: A description of how allelic frequency databases are used in forensic science.
9. Population Structure and its Influence on Allelic Frequency Estimation: A detailed discussion of population substructure and its implications for accurate allelic frequency estimation.
| allelic frequency definition biology: Advanced Topics in Forensic DNA Typing: Interpretation John M. Butler, 2014-07-28 Advanced Topics in Forensic DNA Typing: Interpretation builds upon the previous two editions of John Butler's internationally acclaimed Forensic DNA Typing textbook with forensic DNA analysts as its primary audience. Intended as a third-edition companion to the Fundamentals of Forensic DNA Typing volume published in 2010 and Advanced Topics in Forensic DNA Typing: Methodology published in 2012, this book contains 16 chapters with 4 appendices providing up-to-date coverage of essential topics in this important field. Over 80 % of the content of this book is new compared to previous editions. - Provides forensic DNA analysts coverage of the crucial topic of DNA mixture interpretation and statistical analysis of DNA evidence - Worked mixture examples illustrate the impact of different statistical approaches for reporting results - Includes allele frequencies for 24 commonly used autosomal STR loci, the revised Quality Assurance Standards which went into effect September 2011 |
| allelic frequency definition biology: Genetics for Surgeons Patrick John Morrison, Roy Archibald Joseph Spence, 2005 Morrison (human genetics, University of Ulster, UK) and Spence (biomedical science, University of Ulster, UK) offer an accessible reference on the genetic disorders that surgeons can expect to meet in general surgical practice. Written in non-technical language, with a glossary, list of abbreviations, and color and b&w photos and medical images, the book supplies an introduction to the nomenclature and technology of molecular biology, and will be a useful starting point for those who wish to extend their knowledge. Annotation :2005 Book News, Inc., Portland, OR (booknews.com). |
| allelic frequency definition biology: Brenner's Encyclopedia of Genetics Stanley Maloy, Kelly Hughes, 2013-03-03 The explosion of the field of genetics over the last decade, with the new technologies that have stimulated research, suggests that a new sort of reference work is needed to keep pace with such a fast-moving and interdisciplinary field. Brenner's Encyclopedia of Genetics, Second Edition, Seven Volume Set, builds on the foundation of the first edition by addressing many of the key subfields of genetics that were just in their infancy when the first edition was published. The currency and accessibility of this foundational content will be unrivalled, making this work useful for scientists and non-scientists alike. Featuring relatively short entries on genetics topics written by experts in that topic, Brenner's Encyclopedia of Genetics, Second Edition, Seven Volume Set provides an effective way to quickly learn about any aspect of genetics, from Abortive Transduction to Zygotes. Adding to its utility, the work provides short entries that briefly define key terms, and a guide to additional reading and relevant websites for further study. Many of the entries include figures to explain difficult concepts. Key terms in related areas such as biochemistry, cell, and molecular biology are also included, and there are entries that describe historical figures in genetics, providing insights into their careers and discoveries. This 7-volume set represents a 25% expansion from the first edition, with over 1600 articles encompassing this burgeoning field Thoroughly up-to-date, with many new topics and subfields covered that were in their infancy or not inexistence at the time of the first edition. Timely coverage of emergent areas such as epigenetics, personalized genomic medicine, pharmacogenetics, and genetic enhancement technologies Interdisciplinary and global in its outlook, as befits the field of genetics Brief articles, written by experts in the field, which not only discuss, define, and explain key elements of the field, but also provide definition of key terms, suggestions for further reading, and biographical sketches of the key people in the history of genetics |
| allelic frequency definition biology: Plant Growth and Development Lalit M. Srivastava, 2002-08-27 This book provides current information on synthesis of plant hormones, how their concentrations are regulated, and how they modulate various plant processes. It details how plants sense and tolerate such factors as drought, salinity, and cold temperature, factors that limit plant productivity on earth. It also explains how plants sense two other environmental signals, light and gravity, and modify their developmental patterns in response to those signals. This book takes the reader from basic concepts to the most up-to-date thinking on these topics. * Provides clear synthesis and review of hormonal and environmental regulation of plant growth and development * Contains more than 600 illustrations supplementary information on techniques and/or related topics of interest * Single-authored text provides uniformity of presentation and integration of the subject matter * References listed alphabetically in each section |
| allelic frequency definition biology: Biology for AP ® Courses Julianne Zedalis, John Eggebrecht, 2017-10-16 Biology for AP® courses covers the scope and sequence requirements of a typical two-semester Advanced Placement® biology course. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology for AP® Courses was designed to meet and exceed the requirements of the College Board’s AP® Biology framework while allowing significant flexibility for instructors. Each section of the book includes an introduction based on the AP® curriculum and includes rich features that engage students in scientific practice and AP® test preparation; it also highlights careers and research opportunities in biological sciences. |
| allelic frequency definition biology: The Evaluation of Forensic DNA Evidence National Research Council, Division on Earth and Life Studies, Commission on Life Sciences, Committee on DNA Forensic Science: An Update, 1996-12-12 In 1992 the National Research Council issued DNA Technology in Forensic Science, a book that documented the state of the art in this emerging field. Recently, this volume was brought to worldwide attention in the murder trial of celebrity O. J. Simpson. The Evaluation of Forensic DNA Evidence reports on developments in population genetics and statistics since the original volume was published. The committee comments on statements in the original book that proved controversial or that have been misapplied in the courts. This volume offers recommendations for handling DNA samples, performing calculations, and other aspects of using DNA as a forensic toolâ€modifying some recommendations presented in the 1992 volume. The update addresses two major areas: Determination of DNA profiles. The committee considers how laboratory errors (particularly false matches) can arise, how errors might be reduced, and how to take into account the fact that the error rate can never be reduced to zero. Interpretation of a finding that the DNA profile of a suspect or victim matches the evidence DNA. The committee addresses controversies in population genetics, exploring the problems that arise from the mixture of groups and subgroups in the American population and how this substructure can be accounted for in calculating frequencies. This volume examines statistical issues in interpreting frequencies as probabilities, including adjustments when a suspect is found through a database search. The committee includes a detailed discussion of what its recommendations would mean in the courtroom, with numerous case citations. By resolving several remaining issues in the evaluation of this increasingly important area of forensic evidence, this technical update will be important to forensic scientists and population geneticistsâ€and helpful to attorneys, judges, and others who need to understand DNA and the law. Anyone working in laboratories and in the courts or anyone studying this issue should own this book. |
| allelic frequency definition biology: Encyclopedia of Evolutionary Biology , 2016-04-14 Encyclopedia of Evolutionary Biology, Four Volume Set is the definitive go-to reference in the field of evolutionary biology. It provides a fully comprehensive review of the field in an easy to search structure. Under the collective leadership of fifteen distinguished section editors, it is comprised of articles written by leading experts in the field, providing a full review of the current status of each topic. The articles are up-to-date and fully illustrated with in-text references that allow readers to easily access primary literature. While all entries are authoritative and valuable to those with advanced understanding of evolutionary biology, they are also intended to be accessible to both advanced undergraduate and graduate students. Broad topics include the history of evolutionary biology, population genetics, quantitative genetics; speciation, life history evolution, evolution of sex and mating systems, evolutionary biogeography, evolutionary developmental biology, molecular and genome evolution, coevolution, phylogenetic methods, microbial evolution, diversification of plants and fungi, diversification of animals, and applied evolution. Presents fully comprehensive content, allowing easy access to fundamental information and links to primary research Contains concise articles by leading experts in the field that ensures current coverage of each topic Provides ancillary learning tools like tables, illustrations, and multimedia features to assist with the comprehension process |
| allelic frequency definition biology: Population Genetics John H. Gillespie, 2004-08-06 Publisher Description |
| allelic frequency definition biology: Molecular Diagnosis of Genetic Diseases Rob Elles, 2008-02-01 This completely revised and updated second edition to integrates the many new technologies and insights now available for the diagnosis of genetic diseases. The authors use such methodologies as PCR optimization dosage analysis, mutation scanning, and quantitative fluorescent PCR for aneuploidy analysis, Neurofibromatosis type 1, and Duchenne muscular dystrophy. These largely generic methodologies may be adapted to most genetic conditions for which a molecular diagnosis is relevant, no matter how frequent or rare their incidence. Molecular Diagnosis of Genetic Diseases, Second Edition offers diagnostic molecular geneticists a unique opportunity to sharpen their scientific skills in the design of assays, their execution, and their interpretation. |
| allelic frequency definition biology: Calculations for Molecular Biology and Biotechnology Frank H. Stephenson, 2010-07-30 Calculations for Molecular Biology and Biotechnology: A Guide to Mathematics in the Laboratory, Second Edition, provides an introduction to the myriad of laboratory calculations used in molecular biology and biotechnology. The book begins by discussing the use of scientific notation and metric prefixes, which require the use of exponents and an understanding of significant digits. It explains the mathematics involved in making solutions; the characteristics of cell growth; the multiplicity of infection; and the quantification of nucleic acids. It includes chapters that deal with the mathematics involved in the use of radioisotopes in nucleic acid research; the synthesis of oligonucleotides; the polymerase chain reaction (PCR) method; and the development of recombinant DNA technology. Protein quantification and the assessment of protein activity are also discussed, along with the centrifugation method and applications of PCR in forensics and paternity testing. - Topics range from basic scientific notations to complex subjects like nucleic acid chemistry and recombinant DNA technology - Each chapter includes a brief explanation of the concept and covers necessary definitions, theory and rationale for each type of calculation - Recent applications of the procedures and computations in clinical, academic, industrial and basic research laboratories are cited throughout the text New to this Edition: - Updated and increased coverage of real time PCR and the mathematics used to measure gene expression - More sample problems in every chapter for readers to practice concepts |
| allelic frequency definition biology: Genomics, Circuits, and Pathways in Clinical Neuropsychiatry Thomas Lehner, Bruce L. Miller, Matthew W. State, 2016-06-07 This foundational work comprehensively examines the current state of the genetics, genomics and brain circuitry of psychiatric and neurological disorders. It consolidates discoveries of specific genes and genomic regions associated with these conditions, the genetic and anatomic architecture of these syndromes, and addresses how recent advances in genomics are leading to a reappraisal of the biology underlying clinical neuroscience. In doing so, it critically examines the promise and limitations of these discoveries toward treatment, and to the interdisciplinary nature of understanding brain and behavior. Coverage includes new discoveries regarding autism, epilepsy, intellectual disability, dementias, movement disorders, language impairment, disorders of attention, schizophrenia, and bipolar disorder. Genomics, Circuits, and Pathways in Clinical Neuropsychiatry focuses on key concepts, challenges, findings, and methods in genetics, genomics, molecular pathways, brain circuitry, and related neurobiology of neurologic and psychiatric disorders. - Provides interdisciplinary appeal in psychiatry, neurology, neuroscience, and genetics - Identifies key concepts, methods, and findings - Includes coverage of multiple disorders from autism to schizophrenia - Reviews specific genes associated with disorders - Discusses the genetic architecture of these syndromes - Explains how recent findings are influencing the understanding of biology - Clarifies the promise of these findings for future treatment |
| allelic frequency definition biology: Elements of Evolutionary Genetics Brian Charlesworth, Deborah Charlesworth, 2010-02-03 This textbook shows readers how models of the genetic processes involved in evolution are made (including natural selection, migration, mutation, and genetic drift in finite populations), and how the models are used to interpret classical and molecular genetic data. The material is intended for advanced level undergraduate courses in genetics and evolutionary biology, graduate students in evolutionary biology and human genetics, and researchers in related fields who wish to learn evolutionary genetics. The topics covered include genetic variation, DNA sequence variability and its measurement, the different types of natural selection and their effects (e.g. the maintenance of variation, directional selection, and adaptation), the interactions between selection and mutation or migration, the description and analysis of variation at multiple sites in the genome, genetic drift, and the effects of spatial structure. |
| allelic frequency definition biology: Statistical Population Genomics Julien Y Dutheil, 2020-10-08 This open access volume presents state-of-the-art inference methods in population genomics, focusing on data analysis based on rigorous statistical techniques. After introducing general concepts related to the biology of genomes and their evolution, the book covers state-of-the-art methods for the analysis of genomes in populations, including demography inference, population structure analysis and detection of selection, using both model-based inference and simulation procedures. Last but not least, it offers an overview of the current knowledge acquired by applying such methods to a large variety of eukaryotic organisms. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, pointers to the relevant literature, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, Statistical Population Genomics aims to promote and ensure successful applications of population genomic methods to an increasing number of model systems and biological questions. This work was published by Saint Philip Street Press pursuant to a Creative Commons license permitting commercial use. All rights not granted by the work's license are retained by the author or authors. |
| allelic frequency definition biology: Bioinformatics for Beginners Supratim Choudhuri, 2014-05-09 Bioinformatics for Beginners: Genes, Genomes, Molecular Evolution, Databases and Analytical Tools provides a coherent and friendly treatment of bioinformatics for any student or scientist within biology who has not routinely performed bioinformatic analysis. The book discusses the relevant principles needed to understand the theoretical underpinnings of bioinformatic analysis and demonstrates, with examples, targeted analysis using freely available web-based software and publicly available databases. Eschewing non-essential information, the work focuses on principles and hands-on analysis, also pointing to further study options. - Avoids non-essential coverage, yet fully describes the field for beginners - Explains the molecular basis of evolution to place bioinformatic analysis in biological context - Provides useful links to the vast resource of publicly available bioinformatic databases and analysis tools - Contains over 100 figures that aid in concept discovery and illustration |
| allelic frequency definition biology: Encyclopedia of Genetics Sydney Brenner, Jeffrey H. Miller, William J. Broughton, 2002 The Encyclopedia of Genetics provides the most complete and authoritative coverage of genetics ever published. Dr. Sydney Brenner, the 2002 Nobel Prize winner for Physiology or Medicine, and Professor Jeffrey H. Miller of UCLA have gathered the world's top geneticists to contribute to this outstanding collection. Diverse information is compiled into a single, comprehensive source, containing a clear presentation of cutting-edge knowledge. Easy-to-use and well-organized, the Encyclopedia of Genetics is an invaluable reference work for everyone from the academic researcher to the educated layperson. The Encyclopedia provides: * Comprehensive coverage: at 4 volumes and over 1,700 entries this is the largest Genetics reference work currently available * Complete, up-to-date information * Initial online access to the online version, which includes fully searchable text and numerous hyperlinks to related sites * Cross-references to related articles within the Encyclopedia * 2800 pages; two-color printing throughout text and figures; color plate sections also included.--Provided by publisher |
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| allelic frequency definition biology: Understanding Racial and Ethnic Differences in Health in Late Life National Research Council, Division of Behavioral and Social Sciences and Education, Committee on Population, Panel on Race, Ethnicity, and Health in Later Life, 2004-09-08 As the population of older Americans grows, it is becoming more racially and ethnically diverse. Differences in health by racial and ethnic status could be increasingly consequential for health policy and programs. Such differences are not simply a matter of education or ability to pay for health care. For instance, Asian Americans and Hispanics appear to be in better health, on a number of indicators, than White Americans, despite, on average, lower socioeconomic status. The reasons are complex, including possible roles for such factors as selective migration, risk behaviors, exposure to various stressors, patient attitudes, and geographic variation in health care. This volume, produced by a multidisciplinary panel, considers such possible explanations for racial and ethnic health differentials within an integrated framework. It provides a concise summary of available research and lays out a research agenda to address the many uncertainties in current knowledge. It recommends, for instance, looking at health differentials across the life course and deciphering the links between factors presumably producing differentials and biopsychosocial mechanisms that lead to impaired health. |
| allelic frequency definition biology: The Blood Group Antigen FactsBook Marion E. Reid, Christine Lomas-Francis, Martin L. Olsson, 2012-11-07 The Blood Group Antigen FactsBook has been an essential resource in the hematology, transfusion and immunogenetics fields since its first publication in the late 1990s.The third edition of The Blood Group Antigen FactsBook has been completely revised, updated and expanded to cover all 32 blood group systems. It blends scientific background and clinical applications and provides busy researchers and clinicians with at-a-glance information on over 330 blood group antigens, including history and information on terminology, expression, chromosomal assignment, carrier molecular description, functions, molecular bases of antigens and phenotypes, effect of enzymes/chemicals, clinical significance, disease associations and key references. Includes over 330 entries on blood group antigens in individual factsheetsOffers a logical and concise catalogue structure for each antigen in an improved interior design for quick reference. Written by 3 international experts from the field of immunohematology and transfusion medicine. |
| allelic frequency definition biology: Science as a Way of Knowing John Alexander Moore, 1993 This book makes Moore's wisdom available to students in a lively, richly illustrated account of the history and workings of life. Employing rhetoric strategies including case histories, hypotheses and deductions, and chronological narrative, it provides both a cultural history of biology and an introduction to the procedures and values of science. |
| allelic frequency definition biology: Scientific Frontiers in Developmental Toxicology and Risk Assessment National Research Council, Commission on Life Sciences, Board on Environmental Studies and Toxicology, Committee on Developmental Toxicology, 2000-12-21 Scientific Frontiers in Developmental Toxicology and Risk Assessment reviews advances made during the last 10-15 years in fields such as developmental biology, molecular biology, and genetics. It describes a novel approach for how these advances might be used in combination with existing methodologies to further the understanding of mechanisms of developmental toxicity, to improve the assessment of chemicals for their ability to cause developmental toxicity, and to improve risk assessment for developmental defects. For example, based on the recent advances, even the smallest, simplest laboratory animals such as the fruit fly, roundworm, and zebrafish might be able to serve as developmental toxicological models for human biological systems. Use of such organisms might allow for rapid and inexpensive testing of large numbers of chemicals for their potential to cause developmental toxicity; presently, there are little or no developmental toxicity data available for the majority of natural and manufactured chemicals in use. This new approach to developmental toxicology and risk assessment will require simultaneous research on several fronts by experts from multiple scientific disciplines, including developmental toxicologists, developmental biologists, geneticists, epidemiologists, and biostatisticians. |
| allelic frequency definition biology: Biosocial Surveys National Research Council, Division of Behavioral and Social Sciences and Education, Committee on Population, Committee on Advances in Collecting and Utilizing Biological Indicators and Genetic Information in Social Science Surveys, 2008-01-06 Biosocial Surveys analyzes the latest research on the increasing number of multipurpose household surveys that collect biological data along with the more familiar interviewerâ€respondent information. This book serves as a follow-up to the 2003 volume, Cells and Surveys: Should Biological Measures Be Included in Social Science Research? and asks these questions: What have the social sciences, especially demography, learned from those efforts and the greater interdisciplinary communication that has resulted from them? Which biological or genetic information has proven most useful to researchers? How can better models be developed to help integrate biological and social science information in ways that can broaden scientific understanding? This volume contains a collection of 17 papers by distinguished experts in demography, biology, economics, epidemiology, and survey methodology. It is an invaluable sourcebook for social and behavioral science researchers who are working with biosocial data. |
| allelic frequency definition biology: Essential Genetics Daniel L. Hartl, Elizabeth W. Jones, 2006 Completely updated to reflect new discoveries and current thinking in the field, the Fourth Edition of Essential Genetics is designed for the shorter, less comprehensive introductory course in genetics. The text is written in a clear, lively, and concise manner and includes many special features that make the book user friendly. Topics were carefully chosen to provide a solid foundation for understanding the basic processes of gene transmission, mutation, expression, and regulation. The text also helps students develop skills in problem solving, achieve a sense of the social and historical context in which genetics has developed, and become aware of the genetic resources and information available through the Internet. |
| allelic frequency definition biology: Janeway's Immunobiology Kenneth Murphy, Paul Travers, Mark Walport, Peter Walter, 2010-06-22 The Janeway's Immunobiology CD-ROM, Immunobiology Interactive, is included with each book, and can be purchased separately. It contains animations and videos with voiceover narration, as well as the figures from the text for presentation purposes. |
| allelic frequency definition biology: The Genetics of Alcoholism Henri Begleiter, Benjamin Kissin, 1995 This volume provides an in-depth look at the genetic influences that contribute to the development of alcoholism. Part I: Epidemiologic Studies contains five chapters that examine the various approaches employed in the study of the genetics of alcoholism. It provides a historical perspective and details all the essentials of this subject. Part II: Selective Breeding Studies highlights the results of research involving the selective breeding of rodents. This type of research has produced homogenous strains exhibiting specific behavioral responses considered significant in the development and maintenance of alcohol dependence. The studies presented in Part III: Phenotypic Studies investigate and analyze phenotypic markers that serve as correlates to the genotypic determinants of alcoholism. Through its broad scope, this volume provides for the first time a panoramic view of the knowledge available on the hereditary influences of alcoholism. |
| allelic frequency definition biology: Evolution and Selection of Quantitative Traits Bruce Walsh, Michael Lynch, 2018-06-21 Quantitative traits-be they morphological or physiological characters, aspects of behavior, or genome-level features such as the amount of RNA or protein expression for a specific gene-usually show considerable variation within and among populations. Quantitative genetics, also referred to as the genetics of complex traits, is the study of such characters and is based on mathematical models of evolution in which many genes influence the trait and in which non-genetic factors may also be important. Evolution and Selection of Quantitative Traits presents a holistic treatment of the subject, showing the interplay between theory and data with extensive discussions on statistical issues relating to the estimation of the biologically relevant parameters for these models. Quantitative genetics is viewed as the bridge between complex mathematical models of trait evolution and real-world data, and the authors have clearly framed their treatment as such. This is the second volume in a planned trilogy that summarizes the modern field of quantitative genetics, informed by empirical observations from wide-ranging fields (agriculture, evolution, ecology, and human biology) as well as population genetics, statistical theory, mathematical modeling, genetics, and genomics. Whilst volume 1 (1998) dealt with the genetics of such traits, the main focus of volume 2 is on their evolution, with a special emphasis on detecting selection (ranging from the use of genomic and historical data through to ecological field data) and examining its consequences. |
| allelic frequency definition biology: Molecular Photofitting Tony Frudakis Ph.D., 2010-07-19 In the field of forensics, there is a critical need for genetic tests that can function in a predictive or inferential sense, before suspects have been identified, and/or for crimes for which DNA evidence exists but eye-witnesses do not. Molecular Photofitting fills this need by describing the process of generating a physical description of an individual from the analysis of his or her DNA. The molecular photofitting process has been used to assist with the identification of remains and to guide criminal investigations toward certain individuals within the sphere of prior suspects. Molecular Photofitting provides an accessible roadmap for both the forensic scientist hoping to make use of the new tests becoming available, and for the human genetic researcher working to discover the panels of markers that comprise these tests. By implementing population structure as a practical forensics and clinical genomics tool, Molecular Photofitting serves to redefine the way science and history look at ancestry and genetics, and shows how these tools can be used to maximize the efficacy of our criminal justice system. - Explains how physical descriptions of individuals can be generated using only their DNA - Contains case studies that show how this new forensic technology is used in practical application - Includes over 100 diagrams, tables, and photos to illustrate and outline complex concepts |
| allelic frequency definition biology: Dynamics of Cancer Steven A. Frank, 2018-06-05 The onset of cancer presents one of the most fundamental problems in modern biology. In Dynamics of Cancer, Steven Frank produces the first comprehensive analysis of how particular genetic and environmental causes influence the age of onset. The book provides a unique conceptual and historical framework for understanding the causes of cancer and other diseases that increase with age. Using a novel quantitative framework of reliability and multistage breakdown, Frank unifies molecular, demographic, and evolutionary levels of analysis. He interprets a wide variety of observations on the age of cancer onset, the genetic and environmental causes of disease, and the organization of tissues with regard to stem cell biology and somatic mutation. Frank uses new quantitative methods to tackle some of the classic problems in cancer biology and aging: how the rate of increase in the incidence of lung cancer declines after individuals quit smoking, the distinction between the dosage of a chemical carcinogen and the time of exposure, and the role of inherited genetic variation in familial patterns of cancer. This is the only book that presents a full analysis of the age of cancer onset. It is a superb teaching tool and a rich source of ideas for new and experienced researchers. For cancer biologists, population geneticists, evolutionary biologists, and demographers interested in aging, this book provides new insight into disease progression, the inheritance of predisposition to disease, and the evolutionary processes that have shaped organismal design. |
| allelic frequency definition biology: Clinical DNA Variant Interpretation Conxi Lázaro, Jordan Lerner-Ellis, Amanda Spurdle, 2021-02-27 Clinical DNA Variant Interpretation: Theory and Practice, a new volume in the Translational and Applied Genomics series, covers foundational aspects, modes of analysis, technology, disease and disorder specific case studies, and clinical integration. This book provides a deep theoretical background, as well as applied case studies and methodology, enabling researchers, clinicians and healthcare providers to effectively classify DNA variants associated with disease and patient phenotypes. Practical chapters discuss genomic variant interpretation, terminology and nomenclature, international consensus guidelines, population allele frequency, functional evidence transcripts for RNA, proteins, and enzymes, somatic mutations, somatic profiling, and much more. - Compiles best practices, methods and sound evidence for DNA variant classification in one applied volume - Features chapter contributions from international leaders in the field - Includes practical examples of variant classification for common and rare disorders, and across clinical phenotypes |
| allelic frequency definition biology: Human Population Genetics and Genomics Alan R. Templeton, 2018-11-08 Human Population Genetics and Genomics provides researchers/students with knowledge on population genetics and relevant statistical approaches to help them become more effective users of modern genetic, genomic and statistical tools. In-depth chapters offer thorough discussions of systems of mating, genetic drift, gene flow and subdivided populations, human population history, genotype and phenotype, detecting selection, units and targets of natural selection, adaptation to temporally and spatially variable environments, selection in age-structured populations, and genomics and society. As human genetics and genomics research often employs tools and approaches derived from population genetics, this book helps users understand the basic principles of these tools. In addition, studies often employ statistical approaches and analysis, so an understanding of basic statistical theory is also needed. - Comprehensively explains the use of population genetics and genomics in medical applications and research - Discusses the relevance of population genetics and genomics to major social issues, including race and the dangers of modern eugenics proposals - Provides an overview of how population genetics and genomics helps us understand where we came from as a species and how we evolved into who we are now |
| allelic frequency definition biology: Genetic Variation Rafael Trindade Maia, Magnólia De Araújo Campos, 2021-05-19 Genetic diversity is one of the measures of biodiversity and has consequences in biological variation. It is crucial to understand the evolutionary and adaptative processes in all living species. This book is an interdisciplinary and integrated work that will contribute to the knowledge of academics from different areas of biological sciences. This collection of scientific papers was chosen and analyzed to offer readers a broad and integrated view of the importance of genetic diversity in the evolution and adaptation of living beings, as well as practical applications of the information needed to analyze this diversity in different organisms. This book was edited by geneticist researchers and provides academics with up-to-date and quality information on the subject. |
| allelic frequency definition biology: Gene Drives on the Horizon National Academies of Sciences, Engineering, and Medicine, Division on Earth and Life Studies, Board on Life Sciences, Committee on Gene Drive Research in Non-Human Organisms: Recommendations for Responsible Conduct, 2016-08-28 Research on gene drive systems is rapidly advancing. Many proposed applications of gene drive research aim to solve environmental and public health challenges, including the reduction of poverty and the burden of vector-borne diseases, such as malaria and dengue, which disproportionately impact low and middle income countries. However, due to their intrinsic qualities of rapid spread and irreversibility, gene drive systems raise many questions with respect to their safety relative to public and environmental health. Because gene drive systems are designed to alter the environments we share in ways that will be hard to anticipate and impossible to completely roll back, questions about the ethics surrounding use of this research are complex and will require very careful exploration. Gene Drives on the Horizon outlines the state of knowledge relative to the science, ethics, public engagement, and risk assessment as they pertain to research directions of gene drive systems and governance of the research process. This report offers principles for responsible practices of gene drive research and related applications for use by investigators, their institutions, the research funders, and regulators. |
| allelic frequency definition biology: Mutation and Evolution Ronny C. Woodruff, James N. Thompson, 2012-12-06 Although debated since the time of Darwin, the evolutionary role of mutation is still controversial. In over 40 chapters from leading authorities in mutation and evolutionary biology, this book takes a new look at both the theoretical and experimental measurement and significance of new mutation. Deleterious, nearly neutral, beneficial, and polygenic mutations are considered in their effects on fitness, life history traits, and the composition of the gene pool. Mutation is a phenomenon that draws attention from many different disciplines. Thus, the extensive reviews of the literature will be valuable both to established researchers and to those just beginning to study this field. Through up-to-date reviews, the authors provide an insightful overview of each topic and then share their newest ideas and explore controversial aspects of mutation and the evolutionary process. From topics like gonadal mosaicism and mutation clusters to adaptive mutagenesis, mutation in cell organelles, and the level and distribution of DNA molecular changes, the foundation is set for continuing the debate about the role of mutation, fitness, and adaptability. It is a debate that will have profound consequences for our understanding of evolution. |
| allelic frequency definition biology: Mathematical Population Genetics 1 Warren J. Ewens, 2004-01-09 This is the first of a planned two-volume work discussing the mathematical aspects of population genetics with an emphasis on evolutionary theory. This volume draws heavily from the author’s 1979 classic, but it has been revised and expanded to include recent topics which follow naturally from the treatment in the earlier edition, such as the theory of molecular population genetics. |
| allelic frequency definition biology: Mathematical Population Genetics 1 Warren J. Ewens, 2012-10-01 This is the first of a planned two-volume work discussing the mathematical aspects of population genetics with an emphasis on evolutionary theory. This volume draws heavily from the author’s 1979 classic, but it has been revised and expanded to include recent topics which follow naturally from the treatment in the earlier edition, such as the theory of molecular population genetics. |
| allelic frequency definition biology: Lost Sex Isa Schön, Koen Martens, Peter van Dijk, 2009-09-22 Sex is the queen of problems in evolutionary biology. Generations of researchers have investigated one of the last remaining evolutionary paradoxes: why sex exists at all. Given that sexual reproduction is costly from an evolutionary point of view, one could wonder why not all animals and plants reproduce asexually. Dozens of contemporary hypotheses attempt to explain the prevalence of sex and its advantages and predict the early extinction of fully asexual lineages. The major theme of this book is: what is the fate of animal and plant groups in which sex is lost? Initial chapters discuss theory behind asexual life: what major disadvantages do asexual groups have to face, what are the genetic and ecological consequences and what does this theory predict for more applied aspects of asexual life, for example in agricultural pests, diseases as well as in cultural crops such as grapes. Cases studies in many animals (focusing on both invertebrates and vertebrates) and plants reveal parallel, but also singularly novel adaptations to the absence of meiosis and syngamy. And last but not least, are asexuals really doomed to early extinction or do genuine ancient asexuals exist? This book assembles contributions from the most important research groups dealing with asexual evolution in eukaryotes. It is a milestone in research on parthenogenesis and will be useful to undergraduate as well as graduate students and to senior researchers in all fields of evolutionary biology, as the paradox of sex remains its queen of problems. |
| allelic frequency definition biology: Statistical Human Genetics Robert C. Elston, Jaya M. Satagopan, Shuying Sun, 2012-02-04 Recent advances in genetics over the last quarter of a century, especially in molecular techniques, have dramatically reduced the cost of determining genetic markers and hence opened up a field of research that is increasingly helping to detect, prevent and/or cure many diseases that afflict humans. In Statistical Human Genetics: Methods and Protocols expert researchers in the field describe statistical methods and computer programs in the detail necessary to make them more easily accessible to the beginner analyzing data. Written in the highly successful Methods in Molecular BiologyTM series format, with examples of running the programs and interpreting the program outputs, the chapters include the kind of detailed description and implementation advice that is crucial for getting optimal results from human genetic data collected in the laboratory. Thorough and as much as possible intuitive, Statistical Human Genetics: Methods and Protocols aids scientists in understanding the computer programs and analytical procedures they need to use. |
| allelic frequency definition biology: Buckwheat Germplasm in the World Meiliang Zhou, Ivan Kreft, Galina Suvorova, Yu Tang, Sun-Hee Woo, 2018-01-11 Buckwheat Germplasm in the World offers an overview of this globally important crop, including its general characterization and genetic diversity—particularly in Russia, China, India and Eastern Europe. The book presents the latest research on molecular marker development, genetics and phenotype analysis of new wild buckwheat to examine the nutritional values of this pseudocereal crop. Due to its short growth span, ability to grow at high altitudes and the high quality of its protein content, buckwheat is considered an important crop for addressing global food needs. Ideal for researchers and advanced-level students seeking better understanding of the buckwheat germplasm. - Summarizes all the reported and distributed buckwheat species in the world - Offers researchers the ability to exchange resources with each other to breed new cultivars - Classifies buckwheat species based on perennial and annual from their growth span, and self-incompatible or self-compatible from their flower morphology and characterization - Facilitates hybridization of different species |
| allelic frequency definition biology: Plant Evolution Karl J. Niklas, 2016-08-12 Although plants comprise more than 90% of all visible life, and land plants and algae collectively make up the most morphologically, physiologically, and ecologically diverse group of organisms on earth, books on evolution instead tend to focus on animals. This organismal bias has led to an incomplete and often erroneous understanding of evolutionary theory. Because plants grow and reproduce differently than animals, they have evolved differently, and generally accepted evolutionary views—as, for example, the standard models of speciation—often fail to hold when applied to them. Tapping such wide-ranging topics as genetics, gene regulatory networks, phenotype mapping, and multicellularity, as well as paleobotany, Karl J. Niklas’s Plant Evolution offers fresh insight into these differences. Following up on his landmark book The Evolutionary Biology of Plants—in which he drew on cutting-edge computer simulations that used plants as models to illuminate key evolutionary theories—Niklas incorporates data from more than a decade of new research in the flourishing field of molecular biology, conveying not only why the study of evolution is so important, but also why the study of plants is essential to our understanding of evolutionary processes. Niklas shows us that investigating the intricacies of plant development, the diversification of early vascular land plants, and larger patterns in plant evolution is not just a botanical pursuit: it is vital to our comprehension of the history of all life on this green planet. |
| allelic frequency definition biology: Bioinformatics for Geneticists Michael R. Barnes, Ian C. Gray, 2003-07-01 This timely book illustrates the value of bioinformatics, not simply as a set of tools but rather as a science increasingly essential to navigate and manage the host of information generated by genomics and the availability of completely sequenced genomes. Bioinformatics can be used at all stages of genetics research: to improve study design, to assist in candidate gene identification, to aid data interpretation and management and to shed light on the molecular pathology of disease-causing mutations. Written specifically for geneticists, this book explains the relevance of bioinformatics showing how it may be used to enhance genetic data mining and markedly improve genetic analysis. |
| allelic frequency definition biology: Conceptual Breakthroughs in Evolutionary Ecology Laurence Mueller, 2019-11-19 Although biologists recognize evolutionary ecology by name, many only have a limited understanding of its conceptual roots and historical development. Conceptual Breakthroughs in Evolutionary Ecology fills that knowledge gap in a thought-provoking and readable format. Written by a world-renowned evolutionary ecologist, this book embodies a unique blend of expertise in combining theory and experiment, population genetics and ecology. Following an easily-accessible structure, this book encapsulates and chronologizes the history behind evolutionary ecology. It also focuses on the integration of age-structure and density-dependent selection into an understanding of life-history evolution. - Covers over 60 seminal breakthroughs and paradigm shifts in the field of evolutionary biology and ecology - Modular format permits ready access to each described subject - Historical overview of a field whose concepts are central to all of biology and relevant to a broad audience of biologists, science historians, and philosophers of science |
ALLELIC Definition & Meaning - Merriam-Webster
: one of several forms of a gene that determine alternate forms of one or more genetic traits and occupy …
Allele - Wikipedia
An allele[1] is a variant of the sequence of nucleotides at a particular location, or locus, on a DNA molecule. [2] Alleles …
Allele | Definition, Examples, & Facts | Britannica
May 5, 2025 · allele, any one of two or more genes that may occur alternatively at a given site (locus) on a …
Allele - National Human Genome Research Institute
4 days ago · An allele is one of two or more versions of DNA sequence (a single base or a segment of bases) at …
ALLELIC definition in American English - Collins Online Dictio…
2 senses: relating to or derived from an allele any of two or more variants of a gene that have the same relative …
ALLELIC Definition & Meaning - Merriam-Webster
: one of several forms of a gene that determine alternate forms of one or more genetic traits and occupy identical places on two chromosomes having the same genes arranged in the same …
Allele - Wikipedia
An allele[1] is a variant of the sequence of nucleotides at a particular location, or locus, on a DNA molecule. [2] Alleles can differ at a single position through single nucleotide polymorphisms …
Allele | Definition, Examples, & Facts | Britannica
May 5, 2025 · allele, any one of two or more genes that may occur alternatively at a given site (locus) on a chromosome. Alleles may occur in pairs, or there may be multiple alleles affecting …
Allele - National Human Genome Research Institute
4 days ago · An allele is one of two or more versions of DNA sequence (a single base or a segment of bases) at a given genomic location. An individual inherits two alleles, one from …
ALLELIC definition in American English - Collins Online Dictionary
2 senses: relating to or derived from an allele any of two or more variants of a gene that have the same relative position on.... Click for more definitions.
Gene Interactions: Allelic and Non-Allelic | Cell Biology
These kinds of genetic interactions between the alleles of a single gene are referred to as allelic or intra- allelic interactions. Non-allelic or inter-allelic interactions also occur where the …
Allelic - definition of allelic by The Free Dictionary
Define allelic. allelic synonyms, allelic pronunciation, allelic translation, English dictionary definition of allelic. n. Any of the alternative forms of a gene or other homologous DNA sequence.
What does allelic mean? - Definitions.net
Allelic refers to alleles, which are different forms or versions of a gene found at the same place or locus on a chromosome. These varying genes can lead to different expressions of a particular …
allelic, adj. meanings, etymology and more - Oxford English …
What does the adjective allelic mean? There is one meaning in OED's entry for the adjective allelic . See ‘Meaning & use’ for definition, usage, and quotation evidence.
Allelic - Definition, Meaning & Synonyms - Vocabulary.com
Jun 8, 2025 · Whether you’re a teacher or a learner, Vocabulary.com can put you or your class on the path to systematic vocabulary improvement.
