Mapping of quantitative trait loci affecting resistance/susceptibility to Sarcocystis miescheriana in swine.
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.
Reiner
Gerald
G
Department of Veterinary Clinical Sciences, University of Giessen, D-35392 Giessen, Germany. gerald.reiner@vetmed.uni-giessen.de
Kliemt
Damaris
D
Willems
Hermann
H
Berge
Thomas
T
Fischer
Reiner
R
Köhler
Florian
F
Hepp
Sabine
S
Hertrampf
Barbara
B
Daugschies
Arwid
A
Geldermann
Hermann
H
Mackenstedt
Ute
U
Zahner
Horst
H
D000818:Animals; D002874:Chromosome Mapping; D004198:Disease Susceptibility; D005819:Genetic Markers / Q000235:genetics; D020022:Genetic Predisposition to Disease; D006790:Host-Parasite Interactions / Q000235:genetics; D007113:Immunity, Innate / Q000235:genetics*; D040641:Quantitative Trait Loci; D012522:Sarcocystis / Q000472:pathogenicity; D012523:Sarcocystosis / Q000235:genetics / Q000662:veterinary*; D013552:Swine; D013553:Swine Diseases / Q000235:genetics* / Q000469:parasitology
D005819:Genetic Markers