Estimation of the proportion of genetic variance explained by molecular markers
Autor(a) principal: | |
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Data de Publicação: | 1998 |
Outros Autores: | |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Genetics and Molecular Biology |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000400025 |
Resumo: | Estimation of the proportion of genetic variance explained by molecular markers (p) plays an important role in basic studies of quantitative traits, as well as in marker-assisted selection (MAS), if the selection index proposed by Lande and Thompson (Genetics 124: 743-756, 1990) is used. Frequently, the coefficient of determination (R2) is used to account for this proportion. In the present study, a simple estimator of p is presented, which is applicable when a multiple regression approach is used, and progenies are evaluated in replicated trials. The associated sampling distribution was obtained and compared with that of R2. Simulations indicated that, when the number of evaluated progenies is small, the statistics are not satisfactory, in general, due to bias and/or low precision. Coefficient R2 was found adequate in situations where p is high. If a large number of progenies is evaluated (say, a few hundreds), then the proposed estimator <img src="http:/img/fbpe/gmb/v21n4/1974f1.jpg" alt="1974f1.jpg (1159 bytes)" align="middle"> appears to be better, with acceptable precision and considerably lower bias than R2. A normal approximation to the sampling distribution of <img src="http:/img/fbpe/gmb/v21n4/1974f1.jpg" alt="1974f1.jpg (1159 bytes)" align="middle"> is given, using Taylor's expansion of the expectation and variance of this statistic. Approximate confidence intervals for p, based on normal distribution, are reasonable, if the number of progenies is large. The use of <img src="http:/img/fbpe/gmb/v21n4/1974f1.jpg" alt="1974f1.jpg (1159 bytes)" align="middle"> in MAS is illustrated for estimation of the weight given to the molecular score, when a selection index is used. |
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Estimation of the proportion of genetic variance explained by molecular markersEstimation of the proportion of genetic variance explained by molecular markers (p) plays an important role in basic studies of quantitative traits, as well as in marker-assisted selection (MAS), if the selection index proposed by Lande and Thompson (Genetics 124: 743-756, 1990) is used. Frequently, the coefficient of determination (R2) is used to account for this proportion. In the present study, a simple estimator of p is presented, which is applicable when a multiple regression approach is used, and progenies are evaluated in replicated trials. The associated sampling distribution was obtained and compared with that of R2. Simulations indicated that, when the number of evaluated progenies is small, the statistics are not satisfactory, in general, due to bias and/or low precision. Coefficient R2 was found adequate in situations where p is high. If a large number of progenies is evaluated (say, a few hundreds), then the proposed estimator <img src="http:/img/fbpe/gmb/v21n4/1974f1.jpg" alt="1974f1.jpg (1159 bytes)" align="middle"> appears to be better, with acceptable precision and considerably lower bias than R2. A normal approximation to the sampling distribution of <img src="http:/img/fbpe/gmb/v21n4/1974f1.jpg" alt="1974f1.jpg (1159 bytes)" align="middle"> is given, using Taylor's expansion of the expectation and variance of this statistic. Approximate confidence intervals for p, based on normal distribution, are reasonable, if the number of progenies is large. The use of <img src="http:/img/fbpe/gmb/v21n4/1974f1.jpg" alt="1974f1.jpg (1159 bytes)" align="middle"> in MAS is illustrated for estimation of the weight given to the molecular score, when a selection index is used.Sociedade Brasileira de Genética1998-12-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000400025Genetics and Molecular Biology v.21 n.4 1998reponame:Genetics and Molecular Biologyinstname:Sociedade Brasileira de Genética (SBG)instacron:SBG10.1590/S1415-47571998000400025info:eu-repo/semantics/openAccessBearzoti,EduardoVencovsky,Rolandeng1999-03-01T00:00:00Zoai:scielo:S1415-47571998000400025Revistahttp://www.gmb.org.br/ONGhttps://old.scielo.br/oai/scielo-oai.php||editor@gmb.org.br1678-46851415-4757opendoar:1999-03-01T00:00Genetics and Molecular Biology - Sociedade Brasileira de Genética (SBG)false |
dc.title.none.fl_str_mv |
Estimation of the proportion of genetic variance explained by molecular markers |
title |
Estimation of the proportion of genetic variance explained by molecular markers |
spellingShingle |
Estimation of the proportion of genetic variance explained by molecular markers Bearzoti,Eduardo |
title_short |
Estimation of the proportion of genetic variance explained by molecular markers |
title_full |
Estimation of the proportion of genetic variance explained by molecular markers |
title_fullStr |
Estimation of the proportion of genetic variance explained by molecular markers |
title_full_unstemmed |
Estimation of the proportion of genetic variance explained by molecular markers |
title_sort |
Estimation of the proportion of genetic variance explained by molecular markers |
author |
Bearzoti,Eduardo |
author_facet |
Bearzoti,Eduardo Vencovsky,Roland |
author_role |
author |
author2 |
Vencovsky,Roland |
author2_role |
author |
dc.contributor.author.fl_str_mv |
Bearzoti,Eduardo Vencovsky,Roland |
description |
Estimation of the proportion of genetic variance explained by molecular markers (p) plays an important role in basic studies of quantitative traits, as well as in marker-assisted selection (MAS), if the selection index proposed by Lande and Thompson (Genetics 124: 743-756, 1990) is used. Frequently, the coefficient of determination (R2) is used to account for this proportion. In the present study, a simple estimator of p is presented, which is applicable when a multiple regression approach is used, and progenies are evaluated in replicated trials. The associated sampling distribution was obtained and compared with that of R2. Simulations indicated that, when the number of evaluated progenies is small, the statistics are not satisfactory, in general, due to bias and/or low precision. Coefficient R2 was found adequate in situations where p is high. If a large number of progenies is evaluated (say, a few hundreds), then the proposed estimator <img src="http:/img/fbpe/gmb/v21n4/1974f1.jpg" alt="1974f1.jpg (1159 bytes)" align="middle"> appears to be better, with acceptable precision and considerably lower bias than R2. A normal approximation to the sampling distribution of <img src="http:/img/fbpe/gmb/v21n4/1974f1.jpg" alt="1974f1.jpg (1159 bytes)" align="middle"> is given, using Taylor's expansion of the expectation and variance of this statistic. Approximate confidence intervals for p, based on normal distribution, are reasonable, if the number of progenies is large. The use of <img src="http:/img/fbpe/gmb/v21n4/1974f1.jpg" alt="1974f1.jpg (1159 bytes)" align="middle"> in MAS is illustrated for estimation of the weight given to the molecular score, when a selection index is used. |
publishDate |
1998 |
dc.date.none.fl_str_mv |
1998-12-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000400025 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000400025 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/S1415-47571998000400025 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
Sociedade Brasileira de Genética |
publisher.none.fl_str_mv |
Sociedade Brasileira de Genética |
dc.source.none.fl_str_mv |
Genetics and Molecular Biology v.21 n.4 1998 reponame:Genetics and Molecular Biology instname:Sociedade Brasileira de Genética (SBG) instacron:SBG |
instname_str |
Sociedade Brasileira de Genética (SBG) |
instacron_str |
SBG |
institution |
SBG |
reponame_str |
Genetics and Molecular Biology |
collection |
Genetics and Molecular Biology |
repository.name.fl_str_mv |
Genetics and Molecular Biology - Sociedade Brasileira de Genética (SBG) |
repository.mail.fl_str_mv |
||editor@gmb.org.br |
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1752122377064415232 |