[Analysis of polymorphism on exon 2 of SLA-DRB in Wuzhishan, Erhualian and Pietrain pigs with PCR-RFLP and PCR-SSCP].

Exon 2 of SLA-DRB gene in three strains of pigs was genotyped by PCR-RFLP and PCR-SSCP methods. The strains involved were Wuzhishan, Erhualian and Pietrain, and the numbers of them were 17, 28 and 28, respectively. After genotyping by PCR-RFLP with Msp I, all pigs showed the same band pattern (143 bp/102 bp) named M. However, four kinds of band patterns were created by Rsa I, that were A:141 bp/93 bp/11 bp, B:111 bp/69 bp/54 bp/11 bp, C:180 bp/54 bp/11 bp and D:93 bp/48 bp/39 bp/54 bp/11 bp. There were different pattern types in various pigs, AA and BB in Wuzhishan pigs, AA, BB and AB in Erhualian pigs, AA, CC and BD in Pietrain pigs. In each strain, A was the dominant band pattern, its frequency in Wuzhishan, Erhualian and Pietrain pigs were 0.69, 0.73 and 0.82, respectively. There were no significant differences in the frequency of A band pattern among these three strains. After genotyping by PCR-SSCP, seven pattern types (alphaalpha, alphadelta, betabeta, gammagamma, alphagamma, deltadelta and betaepsilon) were observed in these three populations. There were alphaalpha, alphadelta and betabeta in Wuzhishan pigs, alphaalpha, gammagamma and alphagamma in Erhualian pigs, and alphaalpha, deltadelta, alphadelta, betaepsilon and betabeta in Pietrain pigs. In each breed, the frequency of a band pattern was the highest in all defined bands. The frequency of delta band pattern followed to alpha band pattern in the populations of Wuzhishan and Pietrain pigs, corresponding to that, the frequencies of alphadelta pattern type were maximal in these two populations. The frequencies of all pattern types analyzed by PCR-RFLP and PCR-SSCP were Hardy-Weinberg Equilibrium in Erhualian populations; however, the same results did not appear in the other two populations.