title: Non-association between Rfp-Y major histocompatibility complex-like genes and susceptibility to Marek's disease virus-induced tumours in 6(3) x 7(2) F2 intercross chickens.
abstract: Marek's disease (MD) is a lymphoproliferative disease caused by a member of the herpesvirus family, and the best understood genetic resistance to MD involves the chicken major histocompatibility complex (MHC) B-complex. Preliminary observations have suggested that MHC-like Rfp-Y genes might also influence the incidence of MD. This study describes the differentiation and definition of unique Rfp-Y genes in inbred lines 6(3) and 7(2), lines that possess identical B-complex genes, but that are resistant or susceptible to MD, respectively. To assess if Rfp-Y genes affect susceptibility to MD, 265 6(3) x 7(2) F2 chickens were challenged with the JM strain of MD virus at 1 week of age and were evaluated for MD lesions at up to 10 weeks of age. Genotyping of the F2 chickens for Rfp-Y haplotypes was performed by restriction fragment length polymorphism analysis of genomic DNA using TaqI and a B-FIV probe. Analysis of variance and interval mapping procedures were used to determine association between the Rfp-Y haplotypes and the phenotypic MD values of the F2 chickens. The cosegregation analysis of 265 F2 chickens indicated that there was no association between Rfp-Y haplotypes and MD susceptibility. Furthermore, the fact that the Rfp-Y haplotypes fit the 1:2:1 segregation ratio and the Rfp-Y allele frequencies did not differ significantly from 0.5 in the full population or in selected subpopulations (of either 40 MD-resistant or 39 MD-susceptible chickens) also indicated that Rfp-Y haplotypes do not significantly influence MD susceptibility. We conclude that Rfp-Y haplotypes do not play a major role in determining the genetic susceptibility to MD in 6(3) x 7(2) F2 White Leghorn chickens.
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Avian Disease & Oncology Laboratory, East Lansing, MI 48823, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Vallejo
authors.forename: G T
authors.initials: GT
authors.lastname: Pharr
authors.forename: H C
authors.initials: HC
authors.lastname: Liu
authors.forename: H H
authors.initials: HH
authors.lastname: Cheng
authors.forename: R L
authors.initials: RL
authors.lastname: Witter
authors.forename: L D
authors.initials: LD
authors.lastname: Bacon
mesh_terms: D000818:Animals; D002645:Chickens / Q000235:genetics*; D003433:Crosses, Genetic; D004198:Disease Susceptibility; D005838:Genotype; D006239:Haplotypes; D008381:Herpesvirus 2, Gallid / Q000302:isolation & purification; D008285:Major Histocompatibility Complex; D008380:Marek Disease / Q000235:genetics* / Q000276:immunology / Q000821:virology; D012150:Polymorphism, Restriction Fragment Length; D014766:Viremia / Q000235:genetics / Q000276:immunology