A study on the minimum number of loci required for genetic evaluation using a finite locus model

Abstract This article uses stochastic simulations with a compartmental epidemic model to quantify the impact of genetic diversity within animal populations on the transmission of infectious disease. Genetic diversity is defined by the number of distinct genotypes in the population conferring resistance to microparasitic (e.g., viral or bacterial) infections. Scenarios include homogeneous populations and populations composed of few (finite-locus model) or many (infinitesimal model) genotypes. Genetic heterogeneity has no impact upon the expected value of the basic reproductive ratio (the primary description of the transmission of infection) but affects the variability of this parameter. Consequently, increasing genetic heterogeneity is associated with an increased probability of minor epidemics and decreased probabilities of both major (catastrophic) epidemics and no epidemics. Additionally, heterogeneity per se is associated with a breakdown in the expected relationship between the basic reproductive ratio and epidemic severity, which has been developed for homogeneous populations, with increasing heterogeneity generally resulting in fewer infected animals than expected. Furthermore, increased heterogeneity is associated with decreased disease-dependent mortality in major epidemics and a complex trend toward decreased duration of these epidemics. In summary, more heterogeneous populations are not expected to suffer fewer epidemics on average, but are less likely to suffer catastrophic epidemics.

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A comparison of alternative methods to compute conditional genotype probabilities for genetic evaluation with finite locus models

Genetics Selection Evolution ◽

10.1186/1297-9686-35-7-585 ◽

2003 ◽

Vol 35 (7) ◽

Cited By ~ 2

Author(s):

Liviu R Totir ◽

Rohan L Fernando ◽

Jack CM Dekkers ◽

Soledad A Fernández ◽

Bernt Guldbrandtsen

Keyword(s):

Genetic Evaluation ◽

Alternative Methods ◽

Finite Locus ◽

Genotype Probabilities

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Genetic evaluation with finite locus models

10.31274/rtd-180813-13181 ◽

2002 ◽

Author(s):

Liviu Radu Totir

Keyword(s):

Genetic Evaluation ◽

Finite Locus

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Analyzing haplodiploid inheritance of insecticide resistance in whitefly biotypes

Bulletin of Entomological Research ◽

10.1017/s0007485308006330 ◽

2009 ◽

Vol 99 (3) ◽

pp. 307-315 ◽

Cited By ~ 13

Author(s):

D.W. Crowder ◽

A.R. Horowitz ◽

B.E. Tabashnik ◽

T.J. Dennehy ◽

I. Denholm ◽

...

Keyword(s):

Insecticide Resistance ◽

Insect Growth Regulator ◽

Analytical Models ◽

New Methods ◽

Locus Model ◽

Minimum Number ◽

Q Biotype ◽

Best Fit ◽

Laboratory Bioassays ◽

B Biotype

AbstractWe developed new methods for analyzing inheritance of insecticide resistance in haplodiploid arthropods and applied them to elucidate resistance of the whitefly Bemisia tabaci (Gennadius) to an insect growth regulator, pyriproxyfen. Two invasive biotypes of this devastating crop pest, the B biotype in Arizona and the Q biotype in Israel, have evolved resistance to pyriproxyfen. Here, we incorporated data from laboratory bioassays and crossing procedures exploiting haplodiploidy into statistical and analytical models to estimate the number of loci affecting pyriproxyfen resistance in strains of both biotypes. In tests with models of one to ten loci, the best fit between expected and observed mortality occurred with a two-locus model for the B biotype strain (QC-02) and for one- and two-locus models for the Q biotype strain (Pyri-R). The estimated minimum number of loci affecting resistance was 1.6 for the B biotype strain and 1.0 for the Q biotype strain. The methods used here can be applied to insecticide resistance and other traits in haplodiploid arthropods.

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Information capacity and bandwidth limitations in the SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152392 ◽

1989 ◽

Vol 47 ◽

pp. 84-85

Author(s):

D. C. Joy ◽

R. D. Bunn

Keyword(s):

Signal To Noise Ratio ◽

Critical Dimension ◽

Information Capacity ◽

Acquisition Time ◽

Signal To Noise ◽

Sem Image ◽

Probe Size ◽

Minimum Number ◽

Noise Ratio ◽

Signal Channel

The information available from an SEM image is limited both by the inherent signal to noise ratio that characterizes the image and as a result of the transformations that it may undergo as it is passed through the amplifying circuits of the instrument. In applications such as Critical Dimension Metrology it is necessary to be able to quantify these limitations in order to be able to assess the likely precision of any measurement made with the microscope.The information capacity of an SEM signal, defined as the minimum number of bits needed to encode the output signal, depends on the signal to noise ratio of the image - which in turn depends on the probe size and source brightness and acquisition time per pixel - and on the efficiency of the specimen in producing the signal that is being observed. A detailed analysis of the secondary electron case shows that the information capacity C (bits/pixel) of the SEM signal channel could be written as :

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Applying Generalizability Theory to Optimize Analysis of Spontaneous Teacher Talk in Elementary Classrooms

Journal of Speech Language and Hearing Research ◽

10.1044/2020_jslhr-19-00118 ◽

2020 ◽

Vol 63 (6) ◽

pp. 1947-1957

Author(s):

Alexandra Hollo ◽

Johanna L. Staubitz ◽

Jason C. Chow

Keyword(s):

Special Education Teachers ◽

Generalizability Theory ◽

Child Outcomes ◽

Elementary Classrooms ◽

Teacher Talk ◽

Group Instruction ◽

Data Set ◽

School Year ◽

Minimum Number ◽

Representative Samples

Purpose Although sampling teachers' child-directed speech in school settings is needed to understand the influence of linguistic input on child outcomes, empirical guidance for measurement procedures needed to obtain representative samples is lacking. To optimize resources needed to transcribe, code, and analyze classroom samples, this exploratory study assessed the minimum number and duration of samples needed for a reliable analysis of conventional and researcher-developed measures of teacher talk in elementary classrooms. Method This study applied fully crossed, Person (teacher) × Session (samples obtained on 3 separate occasions) generalizability studies to analyze an extant data set of three 10-min language samples provided by 28 general and special education teachers recorded during large-group instruction across the school year. Subsequently, a series of decision studies estimated of the number and duration of sessions needed to obtain the criterion g coefficient ( g > .70). Results The most stable variables were total number of words and mazes, requiring only a single 10-min sample, two 6-min samples, or three 3-min samples to reach criterion. No measured variables related to content or complexity were adequately stable regardless of number and duration of samples. Conclusions Generalizability studies confirmed that a large proportion of variance was attributable to individuals rather than the sampling occasion when analyzing the amount and fluency of spontaneous teacher talk. In general, conventionally reported outcomes were more stable than researcher-developed codes, which suggests some categories of teacher talk are more context dependent than others and thus require more intensive data collection to measure reliably.

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