Why have sex? The population genetics of sex and recombination

2006 ◽  
Vol 34 (4) ◽  
pp. 519-522 ◽  
Author(s):  
S.P. Otto ◽  
A.C. Gerstein
Keyword(s):  
Population Genetics ◽  
Finite Number ◽  
Mathematical Models ◽  
Sexual Reproduction ◽  
High Frequency ◽  
Evolutionary Biology ◽  
Reproductive Age ◽  
Complex World ◽  
Theoretical Analyses ◽  
Theoretical Results

One of the greatest puzzles in evolutionary biology is the high frequency of sexual reproduction and recombination. Given that individuals surviving to reproductive age have genomes that function in their current environment, why should they risk shuffling their genes with those of another individual? Mathematical models are especially important in developing predictions about when sex and recombination can evolve, because it is difficult to intuit the outcome of evolution with several interacting genes. Interestingly, theoretical analyses have shown that it is often quite difficult to identify conditions that favour the evolution of high rates of sex and recombination. For example, fitness interactions among genes (epistasis) can favour sex and recombination but only if such interactions are negative, relatively weak and not highly variable. One reason why an answer to the paradox of sex has been so elusive is that our models have focused unduly on populations that are infinite in size, unstructured and isolated from other species. Yet most verbal theories for sex and recombination consider a finite number of genotypes evolving in a biologically and/or physically complex world. Here, we review various hypotheses for why sex and recombination are so prevalent and discuss theoretical results indicating which of these hypotheses is most promising.

Evolution and Selection of Quantitative Traits

2018 ◽  
Author(s):  
Bruce Walsh ◽  
Michael Lynch
Keyword(s):  
Mathematical Models ◽  
Quantitative Genetics ◽  
Complex Traits ◽  
Evolutionary Biology ◽  
Quantitative Traits ◽  
Specific Gene ◽  
Real World Data ◽  
Holistic Treatment ◽  
Genetics And Genomics ◽  
Selection Of

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. This extensive work of reference is suitable for graduate level students as well as professional researchers (both empiricists and theoreticians) in the fields of evolutionary biology, genetics, and genomics. It will also be of particular relevance and use to plant and animal breeders, human geneticists, and statisticians.

A Primer of Population Genetics and Genomics

2020 ◽  
Author(s):  
Daniel L. Hartl
Keyword(s):  
Population Genetics ◽  
Complex Traits ◽  
Evolutionary Biology ◽  
Knowledge Retention ◽  
Learning By Doing ◽  
Human Populations ◽  
Gene Drive ◽  
Molecular Population Genetics ◽  
Genetics And Genomics ◽  
And Mathematics

A Primer of Population Genetics and Genomics, 4th edition, has been completely revised and updated to provide a concise but comprehensive introduction to the basic concepts of population genetics and genomics. Recent textbooks have tended to focus on such specialized topics as the coalescent, molecular evolution, human population genetics, or genomics. This primer bucks that trend by encouraging a broader familiarity with, and understanding of, population genetics and genomics as a whole. The overview ranges from mating systems through the causes of evolution, molecular population genetics, and the genomics of complex traits. Interwoven are discussions of ancient DNA, gene drive, landscape genetics, identifying risk factors for complex diseases, the genomics of adaptation and speciation, and other active areas of research. The principles are illuminated by numerous examples from a wide variety of animals, plants, microbes, and human populations. The approach also emphasizes learning by doing, which in this case means solving numerical or conceptual problems. The rationale behind this is that the use of concepts in problem-solving lead to deeper understanding and longer knowledge retention. This accessible, introductory textbook is aimed principally at students of various levels and abilities (from senior undergraduate to postgraduate) as well as practising scientists in the fields of population genetics, ecology, evolutionary biology, computational biology, bioinformatics, biostatistics, physics, and mathematics.

scholarly journals A Nonlinear Consensus Protocol of Multiagent Systems Considering Measuring Errors

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaochu Wang ◽  
Kaichun Zhao ◽  
Zheng You ◽  
Lungui Zheng
Keyword(s):  
Multiagent Systems ◽  
Energy Cost ◽  
Additional Condition ◽  
Consensus Protocol ◽  
Communication Topology ◽  
Measurement Uncertainties ◽  
Theoretical Analyses ◽  
Theoretical Results

In order to avoid a potential waste of energy during consensus controls in the case where there exist measurement uncertainties, a nonlinear protocol is proposed for multiagent systems under a fixed connected undirected communication topology and extended to both the cases with full and partial access a reference. Distributed estimators are utilized to help all agents agree on the understandings of the reference, even though there may be some agents which cannot access to the reference directly. An additional condition is also considered, where self-known configuration offsets are desired. Theoretical analyses of stability are given. Finally, simulations are performed, and results show that the proposed protocols can lead agents to achieve loose consensus and work effectively with less energy cost to keep the formation, which have illustrated the theoretical results.

Minimalist Biological Race

2017 ◽  
Author(s):  
Michael O. Hardimon
Keyword(s):  
Population Genetics ◽  
Evolutionary Biology ◽  
Geographic Location ◽  
Common Ancestry ◽  
Human Beings ◽  
Physical Features ◽  
Biological Race

The minimalist concept of race represents the barest characterization of the ordinary concept race possible. Minimalist races are groups of human beings distinguished by patterns of visible physical features, groups whose members are linked by a common ancestry peculiar to members of the group, and which originate from a distinctive geographic location. Minimalist races exist because there are existing human groups that satisfy the minimalist concept of race. Their existence is not precluded by the findings of population genetics. Appeal to contemporary studies in evolutionary biology and population genetics makes it possible to rebut the objection that minimalist races do not exist because they are not genetically distinct.

Historical Origins

2021 ◽  
pp. 11-45
Author(s):  
J. Arvid Ågren
Keyword(s):  
Population Genetics ◽  
Group Selection ◽  
Evolutionary Biology ◽  
Natural Theology ◽  
Living World ◽  
Selfish Gene ◽  
Theory Of Evolution ◽  
The Third ◽  
Historical Origins ◽  
The Way

This chapter traces the origins of the gene’s-eye view through three sections of evolutionary biology. The first is adaptationism, the tradition that takes the appearance of design in living world to be the cardinal problem a theory of evolution needs to explain. The chapter shows how this view has been especially prominent in British biology, owing the strong standing of natural theology and the writings of William Paley. The second is the emergence of population genetics during the modern synthesis. Here, the work of R.A. Fisher was particularly important. The third and final section was the levels selection debate and the rejection of group selection. G.C. Williams led the way the way and the origin of the gene’s-eye view culminated with the publication of The Selfish Gene.

Evolution: medicine’s most basic science

2010 ◽  
pp. 12-15 ◽  
Author(s):  
Randolph M. Nesse ◽  
Richard Dawkins
Keyword(s):  
Population Genetics ◽  
Basic Science ◽  
Evolutionary Biology ◽  
Phylogenetic Trees ◽  
Evolutionary Methods

The role of evolutionary biology as a basic science for medicine has been expanding rapidly. Some evolutionary methods are already widely applied in medicine, such as population genetics and methods for analysing phylogenetic trees. Newer applications come from seeking evolutionary as well as proximate explanations for disease. ...

Evolution: Medicine’s most basic science

2020 ◽  
pp. 39-42
Author(s):  
Randolph M. Nesse ◽  
Richard Dawkins
Keyword(s):  
Population Genetics ◽  
Natural Selection ◽  
Basic Science ◽  
Evolutionary Biology ◽  
Phylogenetic Trees ◽  
The Body ◽  
Clinical Implications ◽  
Trade Offs ◽  
The Cost

The role of evolutionary biology as a basic science for medicine is expanding rapidly. Some evolutionary methods are already widely applied in medicine, such as population genetics and methods for analysing phylogenetic trees. Newer applications come from seeking evolutionary as well as proximate explanations for disease. Traditional medical research is restricted to proximate studies of the body’s mechanism, but separate evolutionary explanations are needed for why natural selection has left many aspects of the body vulnerable to disease. There are six main possibilities: mismatch, infection, constraints, trade-offs, reproduction at the cost of health, and adaptive defences. Like other basic sciences, evolutionary biology has limited direct clinical implications, but it provides essential research methods, encourages asking new questions that foster a deeper understanding of disease, and provides a framework that organizes the facts of medicine.

scholarly journals Sewall Wright, 21 December 1889 - 3 March 1988

1990 ◽  
Vol 36 ◽  
pp. 567-579 ◽  
Keyword(s):  
Population Genetics ◽  
Evolutionary Biology ◽  
Natural Populations ◽  
Coat Colour ◽  
Balance Theory ◽  
Theory Of Evolution ◽  
Shifting Balance Theory ◽  
Sewall Wright ◽  
Shifting Balance ◽  
Active Research

Sewall Wright's active life spanned the development of genetics from a new discipline when the principles of inheritance were still being elucidated to the technology of recombinant gene construction and insertion. He was one of the major pioneers of population genetics, which gave a quantitative basis to the studies of evolution, of variation in natural populations and of animal and plant breeding. He contributed most significantly to methods and ideas over a long period, indeed his four volume treatise was written long after he formally ‘retired’ and his last paper (211) was published a few days before his death at the age of 98. In the field of population genetics Wright developed the method of path coefficients, which he used to analyse quantitative genetic variation and relationship, but which has been applied to subjects as diverse as economics, the ideas of inbreeding coefficient and F -statistics which form the basis of analysis of population structure, the theory of variation in gene frequency among populations, and the shifting balance theory of evolution, which remains a topic of active research and controversy. Wright contributed to physiological genetics, notably analysis of the inheritance of coat colour in the guinea pig, and in particular the epistatic relationships among the genes involved. There was a critical interplay between his population and physiological work, in that the analysis of finite populations on the one hand and of epistatic interactions on the other are the bases of Wright’s development of the shifting balance theory. A full and enlightening biography of Sewall Wright which traces his influence on evolutionary biology and his interactions with other important workers was published recently (Provine 1986) and shorter appreciations have appeared since his death, notably by Crow (1988), Wright’s long-time colleague. This biography relies heavily on Provine’s volume, and does no more than summarize Wright’s extensive contributions. Many of his important papers have been reprinted recently (1986).

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