Genetics of Cronartium ribicola. III. Mating System

1996 ◽  
Vol 74 (11) ◽  
pp. 1852-1859 ◽  
Author(s):  
Matthew A. Gitzendanner ◽  
Gayle E. Dupper ◽  
Eleanor E. White ◽  
Brett M. Foord ◽  
Paul D. Hodgskiss ◽  
...  
Keyword(s):  
Mating System ◽  
Genetic Recombination ◽  
Random Mating ◽  
Cronartium Ribicola ◽  
White Pine Blister Rust ◽  
Mendelian Segregation ◽  
Weinberg Equilibrium ◽  
Forest Pathogen ◽  
Genotype Frequencies ◽  
Hardy Weinberg Equilibrium

Lack of genetic markers has hindered the study of the mating system of Cronartium ribicola, an exotic forest pathogen Meeting natural and cultivated white pines throughout North America. Isozymes, randomly amplified polymorphic DNA (RAPDs), and restriction length polymorphisms (RFLPs) were used to study the mating system of this rust. Heterozygosity (outcrossing) in diploid telia was demonstrated by analysis of cultures derived from the meiotic products (basidiospores) of individual telia. Families of basidiospores cultured from single telia were used to test for Mendelian segregation and for conformance of loci to Hardy–Weinberg equilibrium. A total of 18 polymorphic loci were identified with the three marker systems. All except for three RAPD loci showed Mendelian segregation in the single-telium families. To quantify the level of outcrossing, gene and genotype frequencies were calculated for families from a single population. Up to 24 families were surveyed with isozymes, 14 with RAPDs, and 18 with RFLPs. Except for one isozyme locus (MPI) in one sample, all 14 loci tested with these families were in Hardy–Weinberg equilibrium, indicating random mating. Further studies, with a different sample from the same population, showed all three isozyme loci to be in Hardy–Weinberg equilibrium. The three marker systems were consistent as to the amount of variation detected. Resistance selection and breeding programs must consider the implications of genetic recombination that outcrossing affords the rust. Keywords: isozymes, RAPDs, RFLPs, Hardy–Weinberg equilibrium, white pine blister rust.

scholarly journals A test for Hardy-Weinberg equilibrium on the X chromosome for sex-biased admixed populations

2019 ◽  
Author(s):  
Daniel Backenroth ◽  
Shai Carmi
Keyword(s):  
X Chromosome ◽  
Random Mating ◽  
Allele Frequencies ◽  
Ratio Test ◽  
Weinberg Equilibrium ◽  
Genotype Frequencies ◽  
Genome Wide ◽  
Control Step ◽  
Hardy Weinberg Equilibrium ◽  
Males And Females

AbstractGenome-wide scans for deviations from Hardy-Weinberg equilibrium (HWE) are commonly applied to detect genotyping errors. In contrast to the autosomes, genotype frequencies on the X chromosome do not reach HWE within a single generation. Instead, if allele frequencies in males and females initially differ, they oscillate for a few generations towards equilibrium. Several populations world-wide have experienced recent sex-biased admixture, namely, their male and female founders differed in ancestry and thus in allele frequencies. Sex-biased admixture makes testing for HWE difficult on X, because deviations are naturally expected, even under random mating post-admixture and error-free genotyping. In this paper, we develop a likelihood ratio test and a χ2 test that detect deviations from HWE on X while allowing for natural deviations due to sex-biased admixture. We demonstrate by simulations that our tests are powerful for detecting deviations due to non-random mating, while at the same time they do not reject the null under historical sex-biased admixture and random mating thereafter. We also demonstrate that when applied to 1000 Genomes project populations (e.g., as a quality control step), our tests reject fewer SNPs (among those showing frequency differences between the sexes) than other tests.

A Misconception About the Hardy–Weinberg Law

2021 ◽  
pp. 1-3
Author(s):  
Alan E. Stark
Keyword(s):  
Population Genetics ◽  
Mating System ◽  
Random Mating ◽  
Autosomal Locus ◽  
Weinberg Equilibrium ◽  
Numerical Example ◽  
Genotypic Distribution ◽  
Hardy Weinberg Equilibrium

Abstract The Hardy–Weinberg law of population genetics is usually associated with the notion of random mating of parents. A numerical example for a triallelic autosomal locus shows that an uncountable set of mating combinations can maintain Hardy–Weinberg proportions. Therefore, one cannot infer random mating in a population from the observation of Hardy–Weinberg equilibrium. The mating system which ensures that the genotypic distribution of offspring is the same as that of the parents is specified.

scholarly journals The general relationship between average effect and average excess

1987 ◽  
Vol 49 (1) ◽  
pp. 69-70 ◽  
Author(s):  
Alan R. Templeton
Keyword(s):  
Analytical Solution ◽  
Random Mating ◽  
General Relationship ◽  
Single Locus ◽  
Average Effect ◽  
Matrix Notation ◽  
Weinberg Equilibrium ◽  
General Analytical Solution ◽  
Genotype Frequencies ◽  
Hardy Weinberg Equilibrium

SummaryThe average effect and average excess both measure the phenotypic effects of gametes in a population. A matrix notation is introduced that provides a general analytical solution for the average effects at a single locus with k alleles that can be solved for any population regardless of its genotype frequencies. This same notation also provides an easy way of deriving and generalizing to k alleles the well-known relationships between average effects and average excesses that exist under random-mating and regular deviations from Hardy–Weinberg equilibrium due to inbreeding.

Isozyme variation in quaking aspen in Minnesota

1992 ◽  
Vol 22 (4) ◽  
pp. 521-524 ◽  
Author(s):  
Steven T. Lund ◽  
Glenn R. Furnier ◽  
Carl A. Mohn
Keyword(s):  
Gene Flow ◽  
Mating System ◽  
Allele Frequencies ◽  
Quaking Aspen ◽  
Isozyme Variation ◽  
Weinberg Equilibrium ◽  
Genotype Frequencies ◽  
Hardy Weinberg Equilibrium ◽  
Isozyme Loci

Variation at 10 polymorphic isozyme loci was examined for nine populations of quaking aspen (Populustremuloides Michx.) in Minnesota. Mean observed and expected estimates of isozyme heterozygosity were 0.217 and 0.220, respectively, with no significant differences in allele frequencies among populations and no significant deviations from genotype frequencies expected under Hardy–Weinberg equilibrium. These results suggest relatively high levels of gene flow among populations and a mating system involving little inbreeding.

Solving Hardy-Weinberg with Geometry: An Integration of Biology and Math

2017 ◽  
Vol 79 (4) ◽  
pp. 309-312
Author(s):  
Laura A. Schoenle ◽  
Matthew Thomas
Keyword(s):  
Scientific Theory ◽  
Geometric Interpretation ◽  
Student Understanding ◽  
Weinberg Equilibrium ◽  
The Core ◽  
Distributive Property ◽  
Genotype Frequencies ◽  
Hardy Weinberg Equilibrium ◽  
Using Data ◽  
And Mathematics

Introducing Hardy-Weinberg equilibrium into the high school or college classroom can be difficult because many students struggle with the mathematical formalism of the Hardy-Weinberg equations. Despite the potential difficulties, incorporating Hardy-Weinberg into the curriculum can provide students with the opportunity to investigate a scientific theory using data and integrate across the disciplines of biology and mathematics. We present a geometric way to interpret and visualize Hardy-Weinberg equilibrium, allowing students to focus on the core ideas without algebraic baggage. We also introduce interactive applets that draw on the distributive property of mathematics to allow students to experiment in real time. With the applets, students can observe the effects of changing allele frequencies on genotype frequencies in a population at Hardy-Weinberg equilibrium. Anecdotally, we found use of the geometric interpretation led to deeper student understanding of the concepts and improved the students' ability to solve Hardy-Weinberg-related problems. Students can use the ideas and tools provided here to draw connections between the biology and mathematics, as well as between algebra and geometry.

Disequilibrium of Human Platelet Antigen 1 (HPA-1) in U.S. Population

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5466-5466
Author(s):  
Tyler Davi d Hutchinson ◽  
Yuhua Song ◽  
Kevin Trainor ◽  
Ghazala Hashmi
Keyword(s):  
Human Platelet ◽  
Embryo Implantation ◽  
The United States ◽  
Implantation Failure ◽  
Random Group ◽  
Weinberg Equilibrium ◽  
Genotype Frequencies ◽  
Chi Squared ◽  
Human Platelet Antigen ◽  
Hardy Weinberg Equilibrium

Abstract Background: Alloimmunization against Human Platelet Antigens (HPA) is associated with Neonatal Alloimmune Thrombocytopenia (NAIT), post-transfusion purpura and refractoriness for platelet transfusion. A flexible BeadChip™ design was developed to simultaneously detect 22 platelet antigens, including HPA-1, and used to assay over 1,000 random blood donors from across the United States. Methods: Samples from 19 labs/centers from across the country were assayed for 11 HPA loci (HPA-1 through 9, 11 and 15) using the BioArray Solutions HPA Assay. Each locus was independently assessed for Hardy-Weinberg Equilibrium. Results: Allele and genotype frequencies for each locus were reported. Platelet antigens HPA-2 through HPA-9, HPA-11 and HPA-15 were all found to be in Hardy-Weinberg Equilibrium with a Chi-Squared value of <3.84 (1 degree of freedom, 5% confidence interval). HPA-1, however, did not exhibit Hardy-Weinberg Equilibrium yielding a Chi-Squared value of 43.4. Conclusions: After reaffirming there was no sampling preference by inclusion of a second blinded random group, it was acknowledged that HPA-1 did not conform to a Mendelian distribution of alleles. The lower incidence of heterozygote HPA-1 individuals may lend credence to the recent finding by Ivanov et al (Akush Ginekol, 2007) linking the polymorphism in GPIIIa that is responsible for the HPA-1 antigen with embryo implantation failure. Further research may help elucidate the causes behind the HPA-1 disequilibrium and how much implantation failure impacts HPA-1 frequencies.

A Reality Check on Hardy–Weinberg

2013 ◽  
Vol 16 (4) ◽  
pp. 782-789 ◽  
Author(s):  
Alan E. Stark ◽  
Eugene Seneta
Keyword(s):  
Random Mating ◽  
Weinberg Equilibrium ◽  
Reality Check ◽  
Hardy Weinberg Equilibrium ◽  
The Law

G. H. Hardy (1877–1947) and Wilhelm Weinberg (1862–1937) had very different lives, but in the minds of geneticists, the two are inextricably linked through the ownership of an apparently simple law called the Hardy–Weinberg law. We demonstrate that the simplicity is more apparent than real. Hardy derived the well-known trio of frequencies {q2, 2pq, p2} with a concise demonstration, whereas for Weinberg it was the prelude to an ingenious examination of the inheritance of twinning in man. Hardy's recourse to an identity relating to the distribution of types among offspring following random mating, rather than an identity relating to the mating matrix, may be the reason why he did not realize that Hardy–Weinberg equilibrium can be reached and sustained with non-random mating. The phrase ‘random mating’ always comes up in reference to the law. The elusive nature of this phrase is part of the reason for the misunderstandings that occur but also because, as we explain, mathematicians are able to use it in a different way from the man-in-the-street. We question the unthinking appeal to random mating as a model and explanation of the distribution of genotypes even when they are close to Hardy–Weinberg proportions. Such sustained proportions are possible under non-random mating.

scholarly journals Analysis of Prolactin and Kappa-Casein Genes Polymorphism in Four Cattle Breeds in Turkey

2014 ◽  
Vol 14 (4) ◽  
pp. 799-806
Author(s):  
Bilal Akyüz ◽  
Mehmet Ulaş Çınar
Keyword(s):  
Restriction Enzymes ◽  
Chi Square ◽  
Brown Swiss ◽  
Weinberg Equilibrium ◽  
Cattle Breeds ◽  
Genotype Frequencies ◽  
Pcr Rflp ◽  
Chi Square Test ◽  
Hardy Weinberg Equilibrium ◽  
Casein Genes

Abstract The objective of this study was to identify allele and genotype frequencies of CSN3 and PRL genes in four cattle breeds in Turkey. For this purpose, a total of 390 cattle of East Anatolian Red (EAR), Zavot, Brown Swiss (BS) and Simmental (SIM) breeds were genotyped by PCR-RFLP method. A 443 bp fragment of CSN3 and a 156 bp fragment of PRL were amplified and digested with HindIII and RsaI restriction enzymes, respectively. For CSN3 and PRL genes, two types of alleles (A and B) and three types of genotypes (AA, BB, and AB) were observed. The highest frequencies for CSN3-A and CSN3-B alleles were estimated for the EAR breed (0.743) and for the BS breed (0.556), respectively. The highest frequency for PRL-A and PRL-B alleles was estimated for the SIM breed (0.801) and for the BS breed (0.315), respectively. The Chi-square test among the investigated cattle breeds showed that only the Zavot breed was in Hardy-Weinberg equilibrium (HWE) for both loci.

Molecular-genetic analyses of dispersal and breeding behaviour in the Australian termite Coptotermes lacteus: evidence for non-random mating in a swarm-dispersal mating system

2007 ◽  
Vol 55 (4) ◽  
pp. 219 ◽  
Author(s):  
Graham J. Thompson ◽  
Michael Lenz ◽  
Ross H. Crozier ◽  
Bernard J. Crespi
Keyword(s):  
Random Mating ◽  
Molecular Genetic ◽  
Radiata Pine ◽  
Breeding Behaviour ◽  
Genotype Frequencies ◽  
Microsatellite Dna Markers ◽  
Offspring Genotype ◽  
Hardy Weinberg Equilibrium ◽  
Population Viscosity ◽  
F Statistics

We used microsatellite DNA markers to infer the dispersal and breeding behaviour of Coptotermes lacteus, a termite whose large mounds are a conspicuous feature of Australia’s central east coast. We genotyped a subsample of neuter offspring for each of 38 colonies sampled over two spatially separated populations, one in a natural forest and the other in an exotic radiata pine plantation. All colonies showed offspring genotype frequencies consistent with a single reproductive pair. This result confirms that stable monogamy is the normal breeding arrangement for this species and that multi-reproductive colonies are rare. The two study populations were significantly differentiated and the distance separating them (~150 km) is therefore an effective constraint on gene flow. The populations themselves, however, were not noticeably subdivided above the level of colony. This lack of within-population viscosity is unexpected for weakly dispersing species and suggests that local gamete dispersal is in fact quite effective in C. lacteus. Nonetheless, dispersing sexuals do not appear to mate randomly. Instead, all four microsatellite loci are deficient in heterozygotes, indicating that populations are substantially inbred, irrespective of habitat. Evidence from hierarchical F-statistics, spatial genetic autocorrelation and relatedness calculations suggests that deviations from Hardy–Weinberg equilibrium may result from either a preference for non-sibling relatives over totally unrelated mates, or from random mating with viscosity – though evidence for the latter hypothesis was not detected. These findings suggest that swarm-dispersal mating systems, usually considered to produce outbreeding and panmixia, can instead involve a notable degree of non-random mating.

scholarly journals O equilíbrio de Hardy-Weinberg no sistema sanguíneo ABO: um estudo de caso em Engenheiro Coelho – SP

2021 ◽  
Vol 43 ◽  
pp. e16
Author(s):  
Vinícius Freitas de Oliveira ◽  
Guilherme Augusto Pianezzer ◽  
Suzete Maria Silva Afonso
Keyword(s):  
Random Mating ◽  
Natural Populations ◽  
Human Populations ◽  
Gene Frequencies ◽  
Weinberg Equilibrium ◽  
Blood Types ◽  
Infinite Population ◽  
Hardy Weinberg Equilibrium ◽  
And Migration

The genetics of human populations is the branch of Genetics that studies the dynamics of genes in natural populations, aiming at the elucidation of mechanisms that alter their genetic composition. Among the fundamentals of this science is the Hardy-Weinberg Equilibrium, which determines that gene frequencies remain unchanged and genotypic proportions reach a stable balance, obtaining the same constant relation with each other over time. To demonstrate this principle, it is necessary to admit that the studied population is not subject to evolutionary factors or to those that alter genotypic frequencies, increasing the homozygosity. More specifically, it is necessary to assume that the population obeys the following premises: random mating, infinite population, non-overlapping generations, in addition to the absence of mutation, selection and migration. More than recalling basic concepts of Genetics and Statistics, this article aims to describe the Bernstein Method for verifying the gene equilibrium for blood types. The research is concluded with a case study in the city of Engenheiro Coelho - SP, where the Hardy-Weinberg Equilibrium for blood types in the population is verified.

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