Evaluation of the generalized likelihood ratio test of hypotheses on the genetic control of continuous traits
Autor(a) principal: | |
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Data de Publicação: | 2004 |
Outros Autores: | , |
Tipo de documento: | Artigo |
Idioma: | por |
Título da fonte: | Semina. Ciências Agrárias (Online) |
Texto Completo: | https://ojs.uel.br/revistas/uel/index.php/semagrarias/article/view/2252 |
Resumo: | Studies of genetic control in plants are carried out to characterize genetic effects and detect the existence of a major gene and/or genes of minor effects (polygenes). If the trait of interest is continuous, the likelihood can be constructed based on a model with mixtures of normal densities. Once exact tests are not evident with such models, the likelihood ratio test is generally used, using the chi-square approximation. This work aimed at evaluating such test statistic using computer simulation. Data sets were simulated using generations typical in plant studies, under two conditions of null hypothesis, without a major gene, and without polygenes. The power of the test was evaluated with both types of genes present. Different sample sizes and values of heritability were considered. Results showed that, although the empirical densities of the test statistic departed significantly from a chi-square distribution, under null hypotheses, there was a reasonable control of type I error, with a significance level of 5%. The power of the test was generally high to detect polygenes and major genes. Power is low to detect a major gene only when it explains a low fraction of genetic variation. |
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Semina. Ciências Agrárias (Online) |
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Evaluation of the generalized likelihood ratio test of hypotheses on the genetic control of continuous traitsAvaliação da razão de verossimilhança generalizada em teste de hipóteses sobre o controle genético de características contínuasMixtures of normalMajor geneComputer simulation.Misturas de normaisGene de efeito maiorSimulação de dados.Studies of genetic control in plants are carried out to characterize genetic effects and detect the existence of a major gene and/or genes of minor effects (polygenes). If the trait of interest is continuous, the likelihood can be constructed based on a model with mixtures of normal densities. Once exact tests are not evident with such models, the likelihood ratio test is generally used, using the chi-square approximation. This work aimed at evaluating such test statistic using computer simulation. Data sets were simulated using generations typical in plant studies, under two conditions of null hypothesis, without a major gene, and without polygenes. The power of the test was evaluated with both types of genes present. Different sample sizes and values of heritability were considered. Results showed that, although the empirical densities of the test statistic departed significantly from a chi-square distribution, under null hypotheses, there was a reasonable control of type I error, with a significance level of 5%. The power of the test was generally high to detect polygenes and major genes. Power is low to detect a major gene only when it explains a low fraction of genetic variation.Estudos de herança genética em plantas são realizados para caracterizar os efeitos genéticos e verificar a existência de um gene de efeito maior e/ou de genes de pequeno efeito (“poligenes”). Quando a característica de interesse é contínua, a verossimilhança é baseada em modelos de misturas de densidades normais. Uma vez que não há testes exatos evidentes para julgar a existência de um gene de efeito maior, a razão de verossimilhança generalizada é em geral utilizada, considerando a aproximação de qui-quadrado. Este trabalho objetivou avaliar esta estatística de teste através de simulação em computador. Dados foram simulados, considerando particularidades de genealogia típicas de tais estudos, e duas condições sob a hipótese de nulidade, ou seja, sem a presença de um gene de efeito maior e sem a presença de genes de pequeno efeito (poligenes), para avaliar o controle do erro tipo I. O poder do teste foi avaliado com ambos presentes. No processo de simulação, foram variados o tamanho de amostra e valores do coeficiente de herdabilidade. Resultados indicaram que, embora a distribuição empírica da razão de verossimilhança tenha se desviado significativamente da distribuição de qui-quadrado, houve controle do erro tipo I, considerando um nível de significância nominal de 5%. O poder é elevado para detectar poligenes e gene de efeito maior, em geral. O poder é baixo para detectar gene de efeito maior quando a proporção da variação genética explicada por este é baixa.UEL2004-05-30info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://ojs.uel.br/revistas/uel/index.php/semagrarias/article/view/225210.5433/1679-0359.2004v25n4p281Semina: Ciências Agrárias; Vol. 25 No. 4 (2004); 281-292Semina: Ciências Agrárias; v. 25 n. 4 (2004); 281-2921679-03591676-546Xreponame:Semina. Ciências Agrárias (Online)instname:Universidade Estadual de Londrina (UEL)instacron:UELporhttps://ojs.uel.br/revistas/uel/index.php/semagrarias/article/view/2252/1932Gonçalves, Renata PiresBearzoti, EduardoFerreira, Daniel Furtadoinfo:eu-repo/semantics/openAccess2010-03-17T17:49:01Zoai:ojs.pkp.sfu.ca:article/2252Revistahttp://www.uel.br/revistas/uel/index.php/semagrariasPUBhttps://ojs.uel.br/revistas/uel/index.php/semagrarias/oaisemina.agrarias@uel.br1679-03591676-546Xopendoar:2010-03-17T17:49:01Semina. Ciências Agrárias (Online) - Universidade Estadual de Londrina (UEL)false |
dc.title.none.fl_str_mv |
Evaluation of the generalized likelihood ratio test of hypotheses on the genetic control of continuous traits Avaliação da razão de verossimilhança generalizada em teste de hipóteses sobre o controle genético de características contínuas |
title |
Evaluation of the generalized likelihood ratio test of hypotheses on the genetic control of continuous traits |
spellingShingle |
Evaluation of the generalized likelihood ratio test of hypotheses on the genetic control of continuous traits Gonçalves, Renata Pires Mixtures of normal Major gene Computer simulation. Misturas de normais Gene de efeito maior Simulação de dados. |
title_short |
Evaluation of the generalized likelihood ratio test of hypotheses on the genetic control of continuous traits |
title_full |
Evaluation of the generalized likelihood ratio test of hypotheses on the genetic control of continuous traits |
title_fullStr |
Evaluation of the generalized likelihood ratio test of hypotheses on the genetic control of continuous traits |
title_full_unstemmed |
Evaluation of the generalized likelihood ratio test of hypotheses on the genetic control of continuous traits |
title_sort |
Evaluation of the generalized likelihood ratio test of hypotheses on the genetic control of continuous traits |
author |
Gonçalves, Renata Pires |
author_facet |
Gonçalves, Renata Pires Bearzoti, Eduardo Ferreira, Daniel Furtado |
author_role |
author |
author2 |
Bearzoti, Eduardo Ferreira, Daniel Furtado |
author2_role |
author author |
dc.contributor.author.fl_str_mv |
Gonçalves, Renata Pires Bearzoti, Eduardo Ferreira, Daniel Furtado |
dc.subject.por.fl_str_mv |
Mixtures of normal Major gene Computer simulation. Misturas de normais Gene de efeito maior Simulação de dados. |
topic |
Mixtures of normal Major gene Computer simulation. Misturas de normais Gene de efeito maior Simulação de dados. |
description |
Studies of genetic control in plants are carried out to characterize genetic effects and detect the existence of a major gene and/or genes of minor effects (polygenes). If the trait of interest is continuous, the likelihood can be constructed based on a model with mixtures of normal densities. Once exact tests are not evident with such models, the likelihood ratio test is generally used, using the chi-square approximation. This work aimed at evaluating such test statistic using computer simulation. Data sets were simulated using generations typical in plant studies, under two conditions of null hypothesis, without a major gene, and without polygenes. The power of the test was evaluated with both types of genes present. Different sample sizes and values of heritability were considered. Results showed that, although the empirical densities of the test statistic departed significantly from a chi-square distribution, under null hypotheses, there was a reasonable control of type I error, with a significance level of 5%. The power of the test was generally high to detect polygenes and major genes. Power is low to detect a major gene only when it explains a low fraction of genetic variation. |
publishDate |
2004 |
dc.date.none.fl_str_mv |
2004-05-30 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://ojs.uel.br/revistas/uel/index.php/semagrarias/article/view/2252 10.5433/1679-0359.2004v25n4p281 |
url |
https://ojs.uel.br/revistas/uel/index.php/semagrarias/article/view/2252 |
identifier_str_mv |
10.5433/1679-0359.2004v25n4p281 |
dc.language.iso.fl_str_mv |
por |
language |
por |
dc.relation.none.fl_str_mv |
https://ojs.uel.br/revistas/uel/index.php/semagrarias/article/view/2252/1932 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
UEL |
publisher.none.fl_str_mv |
UEL |
dc.source.none.fl_str_mv |
Semina: Ciências Agrárias; Vol. 25 No. 4 (2004); 281-292 Semina: Ciências Agrárias; v. 25 n. 4 (2004); 281-292 1679-0359 1676-546X reponame:Semina. Ciências Agrárias (Online) instname:Universidade Estadual de Londrina (UEL) instacron:UEL |
instname_str |
Universidade Estadual de Londrina (UEL) |
instacron_str |
UEL |
institution |
UEL |
reponame_str |
Semina. Ciências Agrárias (Online) |
collection |
Semina. Ciências Agrárias (Online) |
repository.name.fl_str_mv |
Semina. Ciências Agrárias (Online) - Universidade Estadual de Londrina (UEL) |
repository.mail.fl_str_mv |
semina.agrarias@uel.br |
_version_ |
1799306057546203136 |