We have utilized the PCR-RELP method to detect the ryanodine receptor(RYR1) gene mutation and to estimate the genotype frequencies of teh RYR1 gene in commercial crossbred pig population.
The exon region(659bp) including point mutation(C →T; Arg →Cys) in the porcine ryanodine receptor gene, which is a causal mutation for PSS, was amplified by PCR and digested with Cfo I restriction enzyme. The RYR1 gene was classified into three genotypes by agarose gel electrophoresis. The normal homozygous(NN) individuals showed two DNA fragments consisted of 493 and 166bp. The mutant homozygous(nn) individuals showed only one DNA fragment of 659bp. Also, all three fragments(659, 493 and 166bp) were showed in heterozygous(Nn) carrier animals. The proportions of normal, carrier and PSS pigs within crossbred population of pigs were 81%, 15% and 4%, respectively.
According to the results of analysis of variance for the association of genotypes of RYR1 of pigs at 30㎏, day age at 90㎏ and average daily gains, the RYR1 nn genotype was very higher than RYR1 NN genotype for day age at 30㎏ with 5% level of significant difference, but no significant difference for association of any other genotypes with day age at 90㎏ and average daily gain in crossbred pigs.
Therefore, DNA diagnosis by using PCR-RELP analysis for the PSS gene was useful for large-scale screening of commercial pigs in the swine industry.
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