ARS | Publication request: MAPPING OF QUANTITATIVE TRAIT LOCI AFFECTING SUSCEPTIBILITY TO MAREK'S DISEASE IN THE CHICKEN

Submitted to: International Marek's Disease Symposium Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: September 7, 1996
Publication Date: N/A

Technical Abstract: The recent development of a genetic map of the chicken enabled us to dissect susceptibility to Marek's disease (MD). The highly inbred lines 63 and 72 which are MD resistant and susceptible, respectively, were mated to create 278 F2 chickens. The F2 chicks were challenged with Marek's disease virus (MDV) at 1 week of age. The chicks were monitored for symptoms of MD up to 10 weeks of age and all were necropsied to evaluate for gross MD lesions; MDV viremia levels were determined 2 weeks post challenge. Sixty-five microsatellite markers selected from the East Lansing genetic map were identified for genotyping selected F2 chicks. ANOVA, interval mapping, and composite interval mapping were used in the QTL analysis. Twenty quantitative trait loci (QTL) each affecting several components of MD susceptibility (e.g., viremia, survival, affected tissues) were identified on 18 linkage groups. Combined, the QTLs explained >90% of the phenotypic variance of each MD susceptibility trait. Most of the QTLs were dominant or overdominant but QTLs affecting MDV viremia were generally recessive. Digenic epistatic interactions were not significant for most of the MD traits except for viremia. This study shows the feasibility for identifying genes affecting disease susceptibility in the chicken using biometrical and molecular tools.