Plant Genome I Conference
Town & Country Conference Center, San Diego, CA, November, 1992.
PG-I: 48pg1
PARAMETERS AFFECTING THE POWER OF INTERVAL MAPPING
William D. Beavis, DMD, Pioneer Hi-Bred Int'l.
Considerable effort has been devoted to understanding the
LOD threshold needed to avoid false positive identification of
quantitative trait loci (QTL). Based on this threshold,
experimental results from F2 derived populations have been
nconsistent. Most comparisons of QTL have beenamong populations,
thus inconsistent results may have genetic explanations. However,
several researchers have studied F2 derived lines from B73xM017
and also have obtained inconsistent results. This prompted a
simulation study of the parameters affecting the power of
interval mapping to consistently detect real QTL. For a LOD
threshold associated with a genome size of 1500 cM, and a genetic
model of simple additive genetic effects, I studied the impact of
sample size (number of F2 derived lines), number and magnitude of
QTL effects, heritability, and density of co-dominant genetic
markers on the power function. The results suggest that most
experimental results to date have been based on inadequate sample
sizes for all table traits with few segregating QTL. Also, these
results provide an explanation for the inconsistent
identification of QTL.
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