Fx. Du et Bw. Woodward, A 2-STAGE HALF-SIB DESIGN FOR MAPPING QUANTITATIVE TRAIT LOCI IN FOODANIMALS, Journal of dairy science, 80(10), 1997, pp. 2580-2591
Daughter and granddaughter half-sib designs for mapping quantitative t
rait loci were modified to increase experimental power. This new desig
n includes a two-stage procedure, in contrast to conventional one-step
half-sib designs. In stage 1, a few progeny of each sire are genotype
d for marker loci. Based on the analyses of stage 1 data, some sires a
re chosen to continue genotyping more progeny for stage 2. When multip
le chromosomes are under investigation, chromosomes and sires for stag
e 2 are selected based on the analysis of stage 1 data. Sire selection
results in increased frequency of heterozygous genotypes of interest
in stage 2 if the markers are linked to those genes. Chromosome select
ion can increase the proportion of chromosomes with segregating quanti
tative trait loci in stage 2 if not all of the chromosomes evaluated i
n stage 1 have segregating quantitative trait loci. Numerical results
indicated that two-stage half-sib designs are generally more powerful
than conventional designs when 1) the noncentrality parameter is moder
ate or larger, 2) larger quantitative trait loci are mapped using tigh
tly linked markers in larger families, and 3) variation is large in nu
mbers and sizes of segregating quantitative trait loci among the chrom
osomes evaluated in stage 1.