Showing papers on "Selection (genetic algorithm) published in 1979"
1 Jan 1979
TL;DR: In this article, the authors present a model based on the Wright-Fisher In.nitely Many Alleles Model and the Cannings (Exchangeable) Model: Two-Alleles 3.4.
Abstract: Contents Preface Introduction 1 Historical Background 1.1 Biometricians, Saltationists and Mendelians 1.2 The Hardy-Weinberg Law 1.3 The Correlation Between Relatives 1.4 Evolution 1.4.1 The Deterministic Theory 1.4.2 Non-Random-Mating Populations 1.4.3 The Stochastic Theory 1.5 Evolved Genetic Phenomena 1.6 Modelling 1.7 Overall Evolutionary Theories 2 Technicalities and Generalizations 2.1 Introduction 2.2 Random Union of Gametes 2.3 Dioecious Populations 2.4 Multiple Alleles 2.5 Frequency-Dependent Selection 2.6 Fertility Selection 2.7 Continuous-Time Models 2.8 Non-Random-Mating Populations 2.9 The Fundamental Theorem of Natural Selection 2.10 Two Loci 2.11 Genetic Loads 2.12 Finite Markov Chains 3 Discrete Stochastic Models 3.1 Introduction 3.2 Wright-Fisher Model: Two Alleles 3.3 The Cannings (Exchangeable) Model: Two Alleles 3.4 Moran Models: Two Alleles 3.5 K-Allele Wright-Fisher Models 3.6 Infinitely Many Alleles Models 3.6.1 Introduction 3.6.2 The Wright-Fisher In.nitely Many Alleles Model 3.6.3 The Cannings In.nitely Many Alleles Model 3.6.4 The Moran In.nitely Many Alleles Model 3.7 The Effective Population Size 3.8 Frequency-Dependent Selection 3.9 Two Loci 4 Diffusion Theory 4.1 Introduction 4.2 The Forward and Backward Kolmogorov Equations 4.3 Fixation Probabilities 4.4 Absorption Time Properties 4.5 The Stationary Distribution 4.6 Conditional Processes 4.7 Diffusion Theory 4.8 Multi-dimensional Processes 4.9 Time Reversibility 4.10 Expectations of Functions of Di.usion Variables 5 Applications of Diffusion Theory 5.1 Introduction 5.2 No Selection or Mutation 5.3 Selection 5.4 Selection: Absorption Time Properties 5.5 One-Way Mutation 5.6 Two-Way Mutation 5.7 Diffusion Approximations andBoundary Conditions 5.8 Random Environments 5.9 Time-Reversal and Age Properties 5.10 Multi-Allele Diffusion Processes 6 Two Loci 6.1 Introduction 6.2 Evolutionary Properties of Mean Fitness 6.3 Equilibrium Points 6.4 Special Models 6.5 Modifier Theory 6.6 Two-Locus Diffusion Processes 6.7 Associative Overdominance and Hitchhiking 6.8 The Evolutionary Advantage of Recombination 6.9 Summary 7 Many Loci 7.1 Introduction 7.2 Notation 7.3 The Random Mating Case 7.3.1 Linkage Disequilibrium, Means and Variances 7.3.2 Recurrence Relations for Gametic Frequencies 7.3.3 Components of Variance 7.3.4 Particular Models 7.4 Non-Random Mating 7.4.1 Introduction 7.4.2 Notation and Theory 7.4.3 Marginal Fitnesses and Average Effects 7.4.4 Implications 7.4.5 The Fundamental Theorem of Natural Selection 7.4.6 Optimality Principles 7.5 The Correlation Between Relatives 7.6 Summary 8 Further Considerations 8.1 Introduction 8.2 What is Fitness? 8.3 Sex Ratio 8.4 Geographical Structure 8.5 Age Structure 8.6 Ecological Considerations 8.7 Sociobiology 9 Molecular Population Genetics: Introduction 9.1 Introduction 9.2 Technical Comments 9.3 In.nitely Many Alleles Models: Population Properties 9.3.1 The Wright-Fisher Model 9.3.2 The Moran Model 9.4 In.nitely Many Sites Models: Population Properties 9.4.1 Introduction 9.4.2 The Wright-Fisher Model 9.4.3 The Moran Model 9.5 Sample Properties of In.nitely Many Alleles Models 9.5.1 Introduction 9.5.2 The Wright-Fisher Model 9.5.3 The Moran Model 9.6 Sample Properties of In.nitely Many Sites Models 9.6.1 Introduction 9.6.2 The Wright-Fisher Model 9.6.3 The Moran Model 9.7 Relation Between In.nitely Many Alleles and Infinitely Many Sites Models 9.8 Genetic Variation Within and Between
1,213 citations
TL;DR: In this article, a synthesis of Bayesian and sample-reuse approaches to the problem of high structure model selection geared to prediction is presented. But this approach is not suitable for high-dimensional models.
Abstract: This article offers a synthesis of Bayesian and sample-reuse approaches to the problem of high structure model selection geared to prediction. Similar methods are used for low structure models. Nested and nonnested paradigms are discussed and examples given.
1,039 citations
TL;DR: In this paper, a linear index of food selection is proposed which avoids most of the statistical and mathematical inadequacies of these indices, and the statistical reliability of each index is shown to be a function of the absolute and relative sample sizes and the relative abundances of the prey species in the environment.
Abstract: Ivlev's electivity index and the forage ratio, two commonly used measures of food selection, are significantly biased when the sizes of the prey samples from the gut of the predator and the habitat are unequal. Approximate confidence-interval expressions are derived for these indices. A stochastic (Monte Carlo) model was used to validate these expressions and to explore the statistical properties of the indices. The statistical reliability of each index is shown to be a function of the absolute and relative sample sizes and the relative abundances of the prey species in the environment. A linear index of food selection is proposed which avoids most of the statistical and mathematical inadequacies of these indices. Regardless of the index used, however, inadequate habitat sampling, differential availability of prey to the predator, and differential digestion of prey may be significant sources of error in the interpretation of food selection data.
546 citations
TL;DR: The evidence for pervasive frequency-dependent selection is now very strong and can explain the maintenance not only of conventional polymorphism but also of continuous variation in both molecular and morphological characters.
Abstract: The existence within natural populations of large amounts of genetic variation in molecules and morphology presents an evolutionary problem. The ‘neutralist’ solution to this problem, that the variation is usually unimportant to the organisms displaying it, has now lost much of its strength. Interpretations that assume widespread heterozygous advantage also face serious difficulties. A resolution is possible in terms of frequency-dependent selection by predators, parasites and competitors. The evidence for pervasive frequency-dependent selection is now very strong. It appears to follow naturally from the behaviour of predators, from the evolutionary lability of parasites, from the ecology of competition and, at the molecular level, from the phenomena of enzyme kinetics. Such selection can explain the maintenance not only of conventional polymorphism but also of continuous variation in both molecular and morphological characters. It can account for the occurrence of diversity within groups of haploid and self-fertilizing organisms, and for the evolution of differences between individuals in their systems of genetic control.
326 citations
TL;DR: The selectivity coefficient (Wi) used by modelers in feeding constructs and the electivity index Ei*, derived here, are recommended instead because they do not suffer from the shortcomings described for Ei and Ei′.
Abstract: The electivity indices Ei and Ei′ of predator–prey interaction are currently used to quantify particle-size selection by grazers. Under conditions of passive, mechanical particle-size selection pre...
284 citations
TL;DR: It is shown, for mutations affecting viability in Drosophila, that truncation selection or reasonable departures therefrom can reduce the mutation load greatly, and this may be one way to reconcile the very high mutation rate of such genes with a small mutation load.
Abstract: Truncation selection is known to be the most efficient form of directional selection. When this is modified so that the fitness increases linearly over a range of one or two standard deviations of the value of the selected character, the efficiency is reduced, but not greatly. When truncation selection is compared to a system in which fitness is strictly proportional to the character value, the relative efficiency of truncation selection is given by f(c)/σ, in which f(c) is the ordinate of the frequency distribution at the truncation point and σ is the standard deviation of the character. It is shown, for mutations affecting viability in Drosophila, that truncation selection or reasonable departures therefrom can reduce the mutation load greatly. This may be one way to reconcile the very high mutation rate of such genes with a small mutation load. The truncation model with directional selection is appropriate for this situation because of the approximate additivity of these mutations. On the other hand, it is doubtful that this simple model can be applied to all genes affecting fitness, for which there are intermediate optima and antagonistic selection among components with negative correlations. Whether nature ranks and truncates, or approximates this behavior, is an empirical question, yet to be answered.
196 citations
Book•
31 Dec 1979
186 citations
TL;DR: The analysis of inversion karyotypes in Drosophila pseudoobscura by Dobzhansky shows how genetic variation is affected by selection and by the size, dynamics, and degree of subdivision of populations.
Abstract: Ecological genetics is the investigation of the influence of ecological factors on the genetic properties of populations, and the influence of genetic structure on their ecological properties. Ideally, these studies should determine how genetic variation is affected by selection and by the size, dynamics, and degree of subdivision of populations; what ecological factors determine the relative fitness of genotypes; and what effect the genetic composition of a population has on such ecological parameters as its density, stability, and ecological amplitude. Many studies have demonstrated selection in natural populations; indeed, the widespread existence of selection is perhaps the only generalization that can be made about ecological genetics. But most studies are incomplete. A few, such as the analysis of inversion karyotypes in Drosophila pseudoobscura by Dobzhansky
155 citations
1 Jan 1979
TL;DR: This chapter is to develop a general framework in which to answer the question: What are the roles of individual, kin, and group selection in the evolution of social behavior?
Abstract: The main intent of this chapter is to develop a general framework in which to answer the question: What are the roles of individual, kin, and group selection in the evolution of social behavior? Evolution occurs when the gene frequencies in a population or species change. Natural selection in response to environmental conditions is the primary source of genetic change in most populations. But what is the unit of selection? Classically, the differential survival and reproduction of individuals, or individual selection, are regarded as the major cause of genie evolution. More recently, units larger than the individual have been proposed. The feasibility of the differential survival and reproduction of groups such as families, demes, trait groups, populations, and species has been examined qualitatively and quantitatively in theory, but few field data exist yet that prove the occurrence of these selection processes in nature.
10 Dec 1979
TL;DR: This paper discusses primitives that support the construction of distributed programs, focussed on primitives in two major areas: modularity and communication.
Abstract: Distributed programs that run on nodes of a network are now technologically feasible, and are well-suited to the needs of organizations. However, our knowledge about how to construct such programs is limited. This paper discusses primitives that support the construction of distributed programs. Attention is focussed on primitives in two major areas: modularity and communication. The issues underlying the selection of the primitives are discussed, especially the issue of providing robust behavior, and various candidates are analyzed. The primitives will ultimately be provided as part of a programming language that will be used to experiment with construction of distributed programs.
TL;DR: Nine generations of direct selection for ovulation rate (OR) were evaluated to determine the magnitude of the correlated response in three litter size and two litter weight traits and none of these estimates of correlated response was significantly different from zero.
Abstract: Nine generations of direct selection for ovulation rate (OR) were evaluated to determine the magnitude of the correlated response in three litter size and two litter weight traits. A total of 387 Select line and 394 Control line litters were included in the ten generations of data. Realized heritabili ty of OR was .42 -+ .06 based on the regression of response (SelectControl) on weighted cumulative selection differential. Regressions of line means on generation number were significant for lit ter birth weight in both lines (-.31 +.12 kg, Select ;.41 -+ .06 kg, Control) and for lit ter weaning weight (-3.4 -+ .8 kg) in the Control line. None of the other regressions of line means on generation number was significantly different from zero. Regressions of line difference (Select-Control) on generation number were .06 -+ .07, .07 -+ .07, .10 _+ .07, .10 +.10 kg and 1.2 -+ .8 kg for total number farrowed (TNF), number farrowed alive (NFA), number weaned (NW), l i t ter birth weight (LBW), and litter weaning weight (LWW), respectively. However, none of these estimates of correlated response was significantly different from zero. Estimates of realized genetic correlation obtained were .07 (OR-TNF), .11 (OR-NFA),
TL;DR: The importance of aggression in acquisition of initial breeding territory by male Red-winged Blackbirds (Agelaius phoeniceus) is assessed.
Abstract: In this paper I assess the importance of aggression in acquisition of initial breeding territory by male Red-winged Blackbirds (Agelaius phoeniceus). The ability to acquire territory is expected to depend upon that portion of male quality determined primarily by intrasexual selection. Darwin (1859, 1871) formulated the theory of sexual selection to account for certain apparent exceptions to his concept of natural selection, but evolutionary biologists now realize that sexual selection is a special case of individual selection relating to the evolutionary implications of competitive mating. Most zoologists agree with Darwin that sexual selection has two phases: intrasexual, usually in the form of competition between males; and intersexual or epigamic, usually in the form of female choice of a mate (Selander 1972, Emlen 1973, Brown 1975, Wilson 1975, but see also Mayr 1972). In practice it is difficult to separate the effects of non-sexual and sexual selection
TL;DR: A continuous, graded form of group selection which does not involve extinction of demes can effectively oppose selection on the individual level against an altruistic allele under fluctuating environments in infinitely large demes among which uniform mixing occurs every generation.
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TL;DR: The Qβ-polymerase-Qβ-RNA system is reviewed and it is suggested that this system provides a useful model of the evolution of haploid genomes under natural selection.
Abstract: The Qβ-polymerase-Qβ-RNA system is reviewed and the evolution of resistance to inhibitors is discussed. It is suggested that this system provides a useful model of the evolution of haploid genomes under natural selection. Consequences for theories of the origins of life are discussed.
TL;DR: In this article, the authors used Maximum Likelihood to estimate variances and covariances when selection within fixed subclasses exists and showed the usefulness of maximum likelihood for estimating variances.
TL;DR: Using approximate multivariate normal distribution methods, it is demonstrated that the condition for selection to result in a specialized phenotype is that the curve of fitness as a function of breeding value be bimodal, which implies that a specialty phenotype is more likely to result the higher is the heritability of the character.
Abstract: When a polygenic character is exposed to natural selection in which the curve giving fitness as a function of phenotype is a mixture of two Gaussian (normal) curves, the population may respond either by evolving to a specialized phenotype near one of the two optimum phenotypes, or by evolving to a generalized phenotype between them. Using approximate multivariate normal distribution methods, it is demonstrated that the condition for selection to result in a specialized phenotype is that the curve of fitness as a function of breeding value be bimodal. This implies that a specialized phenotype is more likely to result the higher is the heritability of the character. Numerical iterations of four-locus models and algebraic analysis of a symmetric two-locus model generally support the conclusions of the normal approximation.
TL;DR: Wade et al. as mentioned in this paper showed that both the group and individual selection treatments resulted in changes in the mean numbers of adult beetles, and that these changes in mean adult numbers occurred rapidly, often within two or three generations, and were large in magnitude, the population size in the group selection treatments differing from that of the control by over 50%.
Abstract: A recent experimental study of the effect of group and individual selection on population size in the flour beetle, Tribolium castaneum (Wade, 1976, 1977) showed that both the group and individual selection treatments resulted in changes in the mean numbers of adult beetles. These changes in mean adult numbers occurred rapidly, often within two or three generations, and were large in magnitude, the population size in the group selection treatments differing from that of the control by over 50%. In this paper I will elucidate the genetic and ecological mechanisms responsible for the observed changes in population size. I begin by reviewing briefly the major populational results and notation of the selection experiments, because all of the data reported here will be discussed in the context of the earlier study. The group selection experiment (Wade, 1976, 1977) consisted of four treatments (48 populations per treatment) labelled for purpose of discussion as follows: Treatment Aselection by the differential extinction and recolonization of populations, i.e., group selection, for greater numbers of adults per population; Treatment B-group selection for fewer numbers of adults per population; Treatment C-no group selection, individual selection within populations was allowed to determine the numbers of adults; Treatment D-random group selection, selection and recolonization of populations were carried out by means of a table of random numbers (cf. Wade, 1976, 1977, for details of the experimental design). After nine generations of selection, the average adult population sizes and the standard errors of the means were 178 ? 8.23 for the A treatment, 20 ? .58 for B, 49 + 5.92 for C, and 69 + 6.35 for D. The relationship among the means of A> D> C > B was highly significant (P < .005, Kruskal-Wallis rank sum test, 48 observations per treatment). In this paper I present the results of experiments designed to reveal treatment similarities and dissimilarities with respect to those "primary characteristics" (cf. 1 through 4 below) and "group interactions" (cf. 5 below) (Park et al., 1961) which are known to influence population size in Tribolium (cf. King and Dawson, 1972; Mertz, 1972; Sokoloff, 1974; for detailed and comprehensive reviews). The characteristics assayed from populations of each of the four treatments were as follows:
TL;DR: Gene arrangement frequencies in the Mexican populations fluctuate within wide bounds, and selection must act to retain the polymorphism in the face of this flux in gene arrangement frequencies, and it is suggested that male mating success plays an important role.
Abstract: Gene arrangement frequencies were determined at two stages in the life history of Drosophila pseudoobscura taken from nature. Three populations in the central highlands of Mexico were each sampled twice during 1976. Gene arrangement frequencies were measured in adult males and in larvae that were the offspring of females collected at the same time. The adult males were in all likelihood a representative sample of those who fathered the larvae produced by the wild females. Differences in gene arrangement frequency between these two life stages should indicate the operation of natural selection. One-third of our comparisons of common gene arrangement frequencies in males and in larvae from the next generation were statistically significant, as were one-third of our comparisons of total frequency arrays in the two life stages. We consider the components of selection that could produce such frequency changes and reason that male mating success must be the major one. Gene arrangement frequencies in the Mexican populations fluctuate within wide bounds. Selection must act to retain the polymorphism in the face of this flux in gene arrangement frequencies, and we suggest that male mating success plays an important role.
Journal Article•
1 Aug 1979
TL;DR: Psychological research concerning several aspects of the relationship between existing knowledge schemata and the processing of text is summarized and knowledge-based determinants of selectivity are shown to contribute effects beyond those predictable from analysis of text-structural properties.
Abstract: Abstract Psychological research concerning several aspects of the relationship between existing knowledge schemata and the processing of text is summarized. Some dynamic aspects of text processing are discussed first. Schema switching produces problems of accomodating the representation of early parts of text as to more recently processed information. The role of knowledge of the world in producing accommodation is emphasized. Situations where schemata need to be maintained rather than altered pose different problems for the integration of text information. Next, issues concerning selectivity in what is remembered from text are considered. Knowledge-based determinants of selectivity (such as the expected future derivability of information, the degree of constraint provided by schemata, and the performance biases produced by attitudes) are shown to contribute effects beyond those predictable from analysis of text-structural properties. The consequences of text and task characteristics and individual processing styles on the relative employment of knowledge-based versus text-based processes are illustrated next. Finally, future directions for schema-theoretic research are suggested.