Vallejo R L, Pharr G T, Liu H C, Cheng H H, Witter R L, Bacon L D
United States Department of Agriculture, Agricultural Research Service, Avian Disease & Oncology Laboratory, East Lansing, MI 48823, USA.
Anim Genet. 1997 Oct;28(5):331-7. doi: 10.1111/j.1365-2052.1997.00178.x.
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.
马立克氏病（MD）是一种由疱疹病毒科成员引起的淋巴细胞增生性疾病，目前对MD的最佳遗传抗性理解涉及鸡主要组织相容性复合体（MHC）B复合体。初步观察表明，MHC样Rfp-Y基因可能也会影响MD的发病率。本研究描述了近交系6(3)和7(2)中独特Rfp-Y基因的分化和定义，这两个品系拥有相同的B复合体基因，但分别对MD具有抗性或易感性。为了评估Rfp-Y基因是否影响对MD的易感性，265只6(3)×7(2) F2代鸡在1周龄时用MD病毒的JM株进行攻毒，并在10周龄时评估MD病变情况。通过使用TaqI和B-FIV探针的基因组DNA限制性片段长度多态性分析对F2代鸡进行Rfp-Y单倍型基因分型。采用方差分析和区间作图程序来确定Rfp-Y单倍型与F2代鸡MD表型值之间的关联。对265只F2代鸡的共分离分析表明，Rfp-Y单倍型与MD易感性之间没有关联。此外，Rfp-Y单倍型符合1:2:1的分离比例，并且在整个群体或选定的亚群体（40只MD抗性鸡或39只MD易感鸡）中，Rfp-Y等位基因频率与0.5没有显著差异，这也表明Rfp-Y单倍型不会显著影响MD易感性。我们得出结论，在6(3)×7(2) F2代白来航鸡中，Rfp-Y单倍型在决定对MD的遗传易感性方面不发挥主要作用。
