title: Microsatellite markers associated with resistance to Marek's disease in commercial layer chickens.
abstract: The objective of the current study was to identify QTL conferring resistance to Marek's disease (MD) in commercial layer chickens. To generate the resource population, 2 partially inbred lines that differed in MD-caused mortality were intermated to produce 5 backcross families. Vaccinated chicks were challenged with very virulent plus (vv+) MD virus strain 648A at 6 d and monitored for MD symptoms. A recent field isolate of the MD virus was used because the lines were resistant to commonly used older laboratory strains. Selective genotyping was employed using 81 microsatellites selected based on prior results with selective DNA pooling. Linear regression and Cox proportional hazard models were used to detect associations between marker genotypes and survival. Significance thresholds were validated by simulation. Seven and 6 markers were significant based on proportion of false positive and false discovery rate thresholds less than 0.2, respectively. Seventeen markers were associated with MD survival considering a comparison-wise error rate of 0.10, which is about twice the number expected by chance, indicating that at least some of the associations represent true effects. Thus, the present study shows that loci affecting MD resistance can be mapped in commercial layer lines. More comprehensive studies are under way to confirm and extend these results.
authors.affiliation: Department of Animal Science, 2255 Kildee Hall, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: McElroy
authors.forename: J C M
authors.initials: JC
authors.lastname: Dekkers
authors.forename: J E
authors.initials: JE
authors.lastname: Fulton
authors.forename: N P
authors.initials: NP
authors.lastname: O'Sullivan
authors.forename: M
authors.initials: M
authors.lastname: Soller
authors.forename: E
authors.initials: E
authors.lastname: Lipkin
authors.forename: W
authors.initials: W
authors.lastname: Zhang
authors.forename: K J
authors.initials: KJ
authors.lastname: Koehler
authors.forename: S J
authors.initials: SJ
authors.lastname: Lamont
authors.forename: H H
authors.initials: HH
authors.lastname: Cheng
mesh_terms: D000818:Animals; D001947:Breeding; D002645:Chickens / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D008380:Marek Disease / Q000235:genetics* / Q000276:immunology; D018895:Microsatellite Repeats / Q000235:genetics*; D010641:Phenotype; D040641:Quantitative Trait Loci / Q000235:genetics