CALCIUM-RELEASE-CHANNEL GENOTYPES IN SEVERAL PIG-POPULATIONS - ASSOCIATIONS WITH HALOTHANE AND CK REACTIONS

DNA of 2985 pigs from different sources were tested for variants of th e calcium-release-channel (CRC) gene. Frequencies of the C allele, ass ociated with stress resistance, were 0.0 for Belgian Landrace, 0.01 fo r Pietrain, 0.54 for German Landrace, 0.86 for German-Landrace sowline , 0.91 for Schwabisch-Hallisches swine, 0.95 for European Wildboar, an d 0.99 for Large White. All 50 Meishan individuals tested were C/C. In the two German Landrace populations more individuals with heterozygou s genotypes were observed than had been expected. These results may in dicate balanced allele frequencies caused by overdominance-type select ion associated with meat quantity. 6.0% of the halothane-positive pigs were C/C or C/T, and 3.6% of the halothane-negative animals were T/T. As some of the pig groups were crossbreeds from extremely divergent s ources (e.g. European Wildboar, Meishan, Pietrain), special gene effec ts may have influenced the phenotypic reaction to halothane. The avera ge CK values vary between pigs of different CRC genotypes, e.g., the C K80 values 2.64 +/- 0.023, 2.83 +/- 0.027, and 3.19 +/- 0.036 were mea sured for individuals of C/C, C/T and T/T, respectively. For the Germa n Landrace, culling according to a threshold of CK80 greater-than-or-e qual-to 2.70 would eliminate 29.1% of C/C, 63.0% of C/T, and 90.4 % of T/T individuals. Whether CK-based selection may be used for further s election in populations with a fixed CRC C allele is discussed.