Jj. Zhu et al., Screening for highly heterozygous chickens in outbred commercial broiler lines to increase detection power for mapping quantitative trait loci, POULTRY SCI, 80(1), 2001, pp. 6-12
Two commercial broiler lines were used in an experiment to map quantitative
trait loci (QTL) affecting disease resistance. Chickens from these lines w
ere genotyped with 27 microsatellite markers to estimate heterozygosity and
polymorphism information content (PIC), the probability that one parent is
heterozygous at a marker locus and the other has a different genotype. Het
erozygosity estimated from allelic frequencies was 0.52 for the two lines;
however, heterozygosity calculated from actual counts of heterozygous loci
was much lower (0.36) than the estimated heterozygosity. The PIC was 0.45 i
n these lines, and average allele number per marker locus was about 3.5. Tw
enty-five males produced from a cross between these two lines were screened
with the DNA markers to select birds with high heterozygosity at marker lo
ci. Mating simulation showed that uninformative matings could be reduced by
about 5% if 12 pairs of males and females with the highest heterozygosity
at marker loci were selected, which was about a 25% reduction in total unin
formative matings. This experiment demonstrated that the heterozygosity and
PIC in commercial broiler lines were low and selection for the birds with
high heterozygosity at marker loci could increase informative content in ch
ickens used in the experiments of QTL mapping, thus increasing detection po
wer for QTL mapping.