Dependency of Concordance Probability on Gene Frequencies in Genetic Systems for the Diagnosis of Twin Zygosity. A Graphical Presentation Enabling the Rapid, Optimal Choice of Genetic System

1979 ◽  
Vol 28 (2) ◽  
pp. 133-137 ◽  
Author(s):  
Seppo Sarna ◽  
Jaakko Kaprio
Keyword(s):  
Relative Effectiveness ◽  
Genetic System ◽  
Optimal Choice ◽  
Graphical Display ◽  
Gene Frequencies ◽  
Dominance Relationships ◽  
Special Cases ◽  
Genetic Systems ◽  
Concordance Probability ◽  
Graphical Presentation

The dependency of probabilities of phenotypic concordance of gene frequencies in three-allele genetic systems is presented. A graphical display enables the rapid comparison of the relative effectiveness of different systems, taking into account dominance relationships within each genetic system. Four or more allele systems can also be approximated, while two-allele systems are considered to be special cases of three-allele ones.

scholarly journals Simulation of Genetic Systems by Automatic Digital Computers VI. Epistasis

1960 ◽  
Vol 13 (2) ◽  
pp. 150 ◽  
Author(s):  
AS Fraser
Keyword(s):  
Monte Carlo ◽  
Population Size ◽  
Monte Carlo Methods ◽  
Slow Rate ◽  
Genetic System ◽  
Small Populations ◽  
Gene Frequencies ◽  
Genetic Systems ◽  
The Relationship ◽  
Digital Computers

Simulation, by Monte Carlo methods, of the effect on the genotype of seleotion against phenotypic extremes has shown that selection will lead to fixation of a simple additive genetic system at an extremely slow rate in all but very small populations. In oomplex epistatio systems, such selection operates to modify the relation of the genotype to the phenotype. The relationship beoomes an S�shaped function. The efficienoy of seleotion is independent of population size. The deviation from initial gene frequencies due to selection is far less per unit decrease of phenotypio variability in the epistatic than in the additive lines.

Distribution of Gene Frequencies and Discrimination Probabilities for 22 Human Blood Genetic Systems in Four Racial Groups

1980 ◽  
Vol 25 (2) ◽  
pp. 12150J ◽  
Author(s):  
B. W. Grunbaum ◽  
Steve Selvin ◽  
B. A. Myhre ◽  
Nello Pace
Keyword(s):  
Human Blood ◽  
Racial Groups ◽  
Gene Frequencies ◽  
Genetic Systems

scholarly journals Selection, Generalized Transmission and the Evolution of Modifier Genes. I. The Reduction Principle

Genetics ◽  
1987 ◽  
Vol 117 (3) ◽  
pp. 559-572
Author(s):  
Lee Altenberg ◽  
Marcus W Feldman
Keyword(s):  
Meiotic Drive ◽  
Genetic System ◽  
Modifier Gene ◽  
Modifier Genes ◽  
Linear Variation ◽  
Reduction Principle ◽  
Genetic Composition ◽  
Special Cases ◽  
And Migration

ABSTRACT Modifier gene models are used to explore the evolution of features of organisms, such as the genetic system, that are not directly involved in the determination of fitness. Recent work has shown that a general "reduction principle" holds in models of selectively neutral modifiers of recombination, mutation, and migration. Here we present a framework for models of modifier genes that shows these reduction results to be part of a more general theory, for which recombination and mutation are special cases.—The deterministic forces that affect the genetic composition of a population can be partitioned into two categories: selection and transmission. Selection includes differential viabilities, fertilities, and mating success. Imperfect transmission occurs as a result of such phenomena as recombination, mutation and migration, meiosis, gene conversion, and meiotic drive. Selectively neutral modifier genes affect transmission, and a neutral modifier gene can evolve only by generating association with selected genes whose transmission it affects.–We show that, in randomly mating populations at equilibrium, imperfect transmission of selected genes allows a variance in their marginal fitnesses to be maintained. This variance in the marginal fitnesses of selected genes is what drives the evolution of neutral modifier genes. Populations with a variance in marginal fitnesses at equilibrium are always subject to invasion by modifier genes that bring about perfect transmission of the selected genes. It is also found, within certain constraints, that for modifier genes producing what we call "linear variation" in the transmission processes, a new modifier allele can invade a population at equilibrium if it reduces the level of imperfect transmission acting on the selected genes, and will be expelled if it increases the level of imperfect transmission. Moreover, the strength of the induced selection on the modifier gene is shown to range up to the order of the departure of the genetic system from perfect transmission.

XI. The hereditary blood factors of the Kurds of Iran

1973 ◽  
Vol 266 (876) ◽  
pp. 195-205 ◽  
Keyword(s):  
Blood Group ◽  
Genetic Variants ◽  
Plasma Proteins ◽  
Dehydrogenase Deficiency ◽  
Genetic System ◽  
Red Cell ◽  
Gene Frequencies ◽  
Red Cell Enzymes ◽  
Blood Specimens ◽  
Glucose 6 Phosphate Dehydrogenase

Blood specimens were collected from 184 Kurds living in those parts of northwest Iran from which many of the Kurdish Jews, tested in Israel, or their parents, came. Tests were done for the antigens of 10 blood group systems, for the genetic variants of six systems of plasma proteins, and of nine systems of red cell enzymes, and for abnormal haemoglobins. The gene frequencies calculated from the results do not differ greatly from those found in neighbouring populations. They also show a general resemblance to those of the Kurdish Jews, except that the latter have a very much higher incidence of glucose 6-phosphate dehydrogenase deficiency. The possible reasons for this marked difference affecting one genetic system only, are discussed.

Basic stress analysis of hyperbolic regimes in plastic media

1980 ◽  
Vol 88 (2) ◽  
pp. 359-369 ◽  
Author(s):  
R. Hill
Keyword(s):  
Stress Analysis ◽  
Yield Condition ◽  
Nonlinear Problems ◽  
Optimal Choice ◽  
Two Dimensional ◽  
Field Equations ◽  
Characteristic Curves ◽  
Special Cases ◽  
Differential Relations ◽  
Plastic Media

AbstractNonlinear problems of two-dimensional deformation or stress in solid continua are considered where the in-plane components of stress are self-equilibrated and subject to a scalar constraint. In applications the latter is often a yield condition for plastic media. Such field equations are frequently hyperbolic, with a pair of characteristic curves through any point. The primary aim is to express the integrable differential relations along the curves in their simplest form, by an optimal choice of coordinates and variables. Special cases of this problem are now classical, but the general case has received little attention and the universal canonic structure of the relations has escaped notice.

scholarly journals Genetic Algebras Associated with Polyploidy

1966 ◽  
Vol 15 (1) ◽  
pp. 1-9 ◽  
Author(s):  
P. Holgate
Keyword(s):  
Population Genetics ◽  
Chromosome Segregation ◽  
Associative Algebras ◽  
Deterministic Theory ◽  
Special Cases ◽  
General Systems ◽  
Genetic Systems ◽  
Special Train ◽  
The Relationship

The relationship between certain non-associative algebras and the deterministic theory of population genetics was first investigated by Etherington (3)-(8), who defined the concepts of baric, train and special train algebras. Gonshor (10) dealt with, among other topics, algebras corresponding to autopolyploidy, on the assumption that chromosome segregation operated. In this paper [ discuss algebras corresponding to more general systems of inheritance among polyploids, which have been discussed without using algebras by Haldane (11), Geiringer (9), Moran (13) and Seyffert (16). These algebras are special cases of what I have defined as segregation algebras, and mixtures of them. All the algebras corresponding to a fixed ploidy have a relationship which I have called special isotopy. An example shows that algebras arise in other genetic systems which are not isotopic to segregation algebras.

scholarly journals Efficient Search, Mapping, and Optimization of Multi-protein Genetic Systems in Diverse Bacteria

2013 ◽  
Author(s):  
Iman Farasat ◽  
Manish Kushwaha ◽  
Jason Collens ◽  
Michael Easterbrook ◽  
Matthew Guido ◽  
...  
Keyword(s):  
Predictive Models ◽  
Search Algorithm ◽  
Genetic System ◽  
System Level ◽  
Response Curves ◽  
Combinatorial Explosion ◽  
Genetic Systems ◽  
Expression Activity ◽  
Rate Limiting

Developing predictive models of multi-protein genetic systems to understand and optimize their behavior remains a combinatorial challenge, particularly when measurement throughput is limited. We developed a computational approach to build predictive models and identify optimal sequences and expression levels, while circumventing combinatorial explosion. Maximally informative genetic system variants were first designed by the RBS Library Calculator, an algorithm to design sequences for efficiently searching a multi-protein expression space across a >10,000-fold range with tailored search parameters and well-predicted translation rates. We validated the algorithm's predictions by characterizing 646 genetic system variants, encoded in plasmids and genomes, expressed in six gram-positive and gram-negative bacterial hosts. We then combined the search algorithm with system-level kinetic modeling, requiring the construction and characterization of 73 variants to build a sequence-expression-activity map (SEAMAP) for a biosynthesis pathway. Using model predictions, we designed and characterized 47 additional pathway variants to navigate its activity space, find optimal expression regions with desired activity response curves, and relieve rate-limiting steps in metabolism. Creating sequence-expression-activity maps accelerates the optimization of many protein systems and allows previous measurements to quantitatively inform future designs.

Genetic systems in the south-west flora: implications for conservation strategies for Australian plant species

2000 ◽  
Vol 48 (3) ◽  
pp. 341 ◽  
Author(s):  
Sidney H. James
Keyword(s):  
Genetic Diversity ◽  
Genetic Load ◽  
Allelic Diversity ◽  
Genetic System ◽  
Plant Population ◽  
Conservation Strategies ◽  
Population System ◽  
Australian Plant ◽  
South West ◽  
Genetic Systems

Is genetic diversity a reliable indicator of evolutionary capability? A comparative study of genetic systems in Australian native plants, particularly from south-west Australia, suggests the primitive condition to be recombinationally capable with low allelic diversity. Diversity has accumulated in some nursery lineages in association with lethal equivalent polymorphisms. This generated an elevated evolutionary capability which allowed escape from the benign nursery into the demanding arid playground. Lethal equivalent polymorphisms also generate a high genetic load which drives genetic system evolution towards the minimisation of that load. Many of the devices which reduce the genetic load, including chiasma localisation at meiosis and reduced chromosome numbers, are impedimenta to recombination and they must reduce evolutionary capability. Thus, to correctly interpret the levels and patterns of genetic diversity within an Australian plant population system we need to know how its genetic system operates and how much it is recombinationally impeded. It may be true that in many Australian plant population systems, the more genetic diversity we see, the less evolutionary potential there is. Conservation strategies based on a misunderstanding of the relevance of genetic diversity in population systems may be quite disastrous.

scholarly journals A generalized Fourier–Hermite method for the Vlasov–Poisson system

2021 ◽  
Author(s):  
Katharina Kormann ◽  
Anna Yurova
Keyword(s):  
Numerical Experiments ◽  
Numerical Scheme ◽  
Hermite Polynomial ◽  
Optimal Choice ◽  
Basis Functions ◽  
Additional Parameter ◽  
Special Cases ◽  
Scaling Parameters ◽  
Improved Accuracy ◽  
Exponential Part

AbstractA generalized Fourier–Hermite semi-discretization for the Vlasov–Poisson equation is introduced. The formulation of the method includes as special cases the symmetrically-weighted and asymmetrically-weighted Fourier–Hermite methods from the literature. The numerical scheme is formulated as a weighted Galerkin method with two separate scaling parameters for the Hermite polynomial and the exponential part of the new basis functions. Exact formulas for the error in mass, momentum, and energy conservation of the method depending on the parameters are devised and $$L^2$$ L 2 stability is discussed. The numerical experiments show that an optimal choice of the additional parameter in the generalized method can yield improved accuracy compared to the existing methods, but also reveal the distinct stability properties of the symmetrically-weighted method.

scholarly journals Sexual conflict, sex allocation and the genetic system

2009 ◽  
Vol 5 (5) ◽  
pp. 682-685 ◽  
Author(s):  
David M. Shuker ◽  
Anna M. Moynihan ◽  
Laura Ross
Keyword(s):  
Sex Ratio ◽  
Sexual Conflict ◽  
Sex Allocation ◽  
Sex Ratios ◽  
Genetic System ◽  
Next Generation ◽  
Evolutionary Conflict ◽  
Genetic Systems ◽  
Males And Females ◽  
Evolutionary Consequences

Decisions over what sex ratio to produce can have far-reaching evolutionary consequences, for both offspring and parents. However, the extent to which males and females come into evolutionary conflict over aspects of sex allocation depends on the genetic system: when genes are passed to the next generation unequally by the two sexes (as in haplodiploidy, for example), this biased transmission can facilitate a range of conflicts not seen in diploids. However, much less attention has been paid to these forms of sexual conflict, not least because it has not always been clear how the conflicts could be realized. Here we consider how biased gene transmission, as expressed in different genetic systems, enhances the opportunity for sex ratio conflict and give empirical examples that confirm that males and females have the opportunity to influence sex ratios.

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