* * * *PLEASE NOTE UNUSUAL DAY AND TIME* * * *
Seminar Notice
Statistical Laboratory
Iowa State University
DATE AND TIME: Tuesday, February 28, 2006, 11:00 a.m.
PLACE: B29 Atanasoff
SPEAKER: Yun Ju Sung, Division of Medical Genetics, University of
Washington, Seattle
TITLE: MCMC Linkage Analysis for Two Genes and a Polygenic Component on
General Pedigrees
ABSTRACT
Linkage analysis involves statistical inference about the location of genes
influencing a trait, using trait and genetic marker data collected on families.
We describe a new approach, implemented in a computer program, for parametric
linkage analysis with a quantitative trait model having one or two genes and a
polygenic component, which models additional familial correlation from other
unlinked genes. Competing programs use simpler models: one gene, one gene plus a
polygenic component, or a crude approximation to the two gene model. Using
simple models when they are incorrect, as for complex traits that are
influenced by multiple genes, can bias estimates and reduce power to detect
linkage. Simulated examples, with various sizes of pedigrees, show that two-gene
analysis correctly identifies the location of both genes, whereas other analyses
based on simpler models fail to identify the location of genes with modest
contributions.
We compute the likelihood with MCMC realization of segregation indicators
at hypothesized gene locations conditional on marker data, summation over phased
multilocus genotypes of founders, and peeling of the polygenic component. This
is the first program for two genes and a polygenic component. It has no
restriction on number of markers or complexity of pedigrees, facilitating use of
more complex models with general pedigrees.
This is joint work with Elizabeth Thompson and Ellen Wijsman.
COFFEE: 10:30 a.m., 104 Snedecor Hall
Jeanette La Grange
Department of Statistics
102 Snedecor
Iowa State University
Ames, IA 50010-1210
515 294-3440 (office)
515 294-4040 (fax)