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| PMID |
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| TITLE |
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| A simulation study of the effects of assignment of prior identity-by-descent probabilities to unselected sib pairs, in covariance-structure modeling of a quantitative-trait locus. |
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| ABSTRACT |
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| Sib pair-selection strategies, designed to identify the most informative sib pairs in order to detect a quantitative-trait locus (QTL), give rise to a missing-data problem in genetic covariance-structure modeling of QTL effects. After selection, phenotypic data are available for all sibs, but marker data-and, consequently, the identity-by-descent (IBD) probabilities-are available only in selected sib pairs. One possible solution to this missing-data problem is to assign prior IBD probabilities (i.e., expected values) to the unselected sib pairs. The effect of this assignment in genetic covariance-structure modeling is investigated in the present paper. Two maximum-likelihood approaches to estimation are considered, the pi-hat approach and the IBD-mixture approach. In the simulations, sample size, selection criteria, QTL-increaser allele frequency, and gene action are manipulated. The results indicate that the assignment of prior IBD probabilities results in serious estimation bias in the pi-hat approach. Bias is also present in the IBD-mixture approach, although here the bias is generally much smaller. The null distribution of the log-likelihood ratio (i.e., in absence of any QTL effect) does not follow the expected null distribution in the pi-hat approach after selection. In the IBD-mixture approach, the null distribution does agree with expectation. |
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| DATE PUBLISHED |
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| HISTORY |
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| PUBSTATUS |
PUBSTATUSDATE |
| pubmed |
1999/01/23 19:27 |
| medline |
2000/03/21 09:00 |
| entrez |
1999/01/23 19:27 |
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| AUTHORS |
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| NAME |
COLLECTIVENAME |
LASTNAME |
FORENAME |
INITIALS |
AFFILIATION |
AFFILIATIONINFO |
| Dolan CV |
|
Dolan |
C V |
CV |
|
Psychology Faculty, University of Amsterdam, The Netherlands. op_dolan@macmail.psy.uva.nl |
| Boomsma DI |
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Boomsma |
D I |
DI |
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| Neale MC |
|
Neale |
M C |
MC |
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| INVESTIGATORS |
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| JOURNAL |
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| VOLUME: 64 |
| ISSUE: 1 |
| TITLE: American journal of human genetics |
| ISOABBREVIATION: Am. J. Hum. Genet. |
| YEAR: 1999 |
| MONTH: Jan |
| DAY: |
| MEDLINEDATE: |
| SEASON: |
| CITEDMEDIUM: Print |
| ISSN: 0002-9297 |
| ISSNTYPE: Print |
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| MEDLINE JOURNAL |
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| MEDLINETA: Am J Hum Genet |
| COUNTRY: United States |
| ISSNLINKING: 0002-9297 |
| NLMUNIQUEID: 0370475 |
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| PUBLICATION TYPE |
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| PUBLICATIONTYPE TEXT |
| Journal Article |
| Research Support, Non-U.S. Gov't |
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| COMMENTS AND CORRECTIONS |
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| GRANTS |
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| GENERAL NOTE |
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| KEYWORDS |
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| MESH HEADINGS |
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| DESCRIPTORNAME |
QUALIFIERNAME |
| Alleles |
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| Gene Frequency |
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| Genetic Markers |
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| Humans |
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| Models, Genetic |
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| Nuclear Family |
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| Quantitative Trait, Heritable |
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| Software |
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| SUPPLEMENTARY MESH |
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| GENE SYMBOLS |
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| CHEMICALS |
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| REGISTRYNUMBER |
NAMEOFSUBSTANCE |
| 0 |
Genetic Markers |
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| OTHER ID's |
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