Reiner Gerald, Kliemt Damaris, Willems Hermann, Berge Thomas, Fischer Reiner, Köhler Florian, Hepp Sabine, Hertrampf Barbara, Daugschies Arwid, Geldermann Hermann, Mackenstedt Ute, Zahner Horst
Department of Veterinary Clinical Sciences, University of Giessen, D-35392 Giessen, Germany.
Genomics. 2007 May;89(5):638-46. doi: 10.1016/j.ygeno.2007.01.011. Epub 2007 Mar 1.
The outcome of infectious diseases in vertebrates is under genetic control at least to some extent. In swine, e.g., marked differences in resistance/susceptibility to Sarcocystis miescheriana have been shown between Chinese Meishan and European Pietrain pigs, and these differences are associated with high heritabilities. A first step toward the identification of genes and polymorphisms causal for these differences may be the mapping of quantitative trait loci (QTLs). Considering clinical, immunological, and parasitological traits in the above model system, this survey represents the first QTL study on parasite resistance in pigs. QTL mapping was performed in 139 F(2) pigs of a Meishan/Pietrain family infected with S. miescheriana. Fourteen genome-wide significant QTLs were mapped to several chromosomal areas. Among others, major QTLs were identified for bradyzoite numbers in skeletal muscles (F = 17.4; p < 0.001) and for S. miescheriana-specific plasma IgG(2) levels determined 42 days p.i. (F = 20.9; p < 0.001). The QTLs were mapped to different regions of chromosome 7, i.e., to the region of the major histocompatibility complex (bradyzoites) and to an immunoglobulin heavy chain cluster, respectively. These results provide evidence for a direct and causal role for gene variants within these gene clusters (cis-acting) in differences in resistance to S. miescheriana.
脊椎动物传染病的结局至少在一定程度上受基因控制。例如，在中国梅山猪和欧洲皮特兰猪之间，已显示出对米氏肉孢子虫的抗性/易感性存在显著差异，且这些差异与高遗传力相关。鉴定导致这些差异的基因和多态性的第一步可能是对数量性状基因座（QTL）进行定位。考虑到上述模型系统中的临床、免疫学和寄生虫学特征，这项调查代表了对猪寄生虫抗性的首次QTL研究。对感染米氏肉孢子虫的梅山/皮特兰家系的139头F(2)猪进行了QTL定位。14个全基因组显著QTL被定位到几个染色体区域。其中，主要QTL被确定为骨骼肌中缓殖子数量（F = 17.4；p < 0.001）以及感染后42天测定的米氏肉孢子虫特异性血浆IgG(2)水平（F = 20.9；p < 0.001）。这些QTL分别被定位到7号染色体的不同区域，即主要组织相容性复合体区域（缓殖子）和免疫球蛋白重链簇区域。这些结果为这些基因簇内的基因变异（顺式作用）在对米氏肉孢子虫抗性差异中起直接因果作用提供了证据。
