Abstract: FSH b subunit gene was regarded as a candidate gene for reproductive traits of Beijing Black Pig in this study. The polymorphism of two loci FSHb-1 and FSHb-2 was detected by electrophoretic method and PCR-RFLP with re
striction endonuclease HaeⅢ. Sequencing results showed that a 273 bp sequence, which was a retrotransponsons including a RNA PolymeraseⅢinter promoter, was inserted between the 134th and 135th nucleotide of the PCR product in FSHb-1, and the mutation (C→T) was revealed at the 173th nucleotide of the PCR product in FSHb-2. Both alleles (A and B) of both
loci were found in the population that showed low polymorphism. Chi-square test indicated that the two polymorphism sites fitted Hardy-Weinberg equilibrium (P>0.05). The effects of polymorphism of FSH b subunit gene on total born number (TNB), number born alive (NBA), and birth weight (WB) were analyzed. For FSHb-1 locus, pigs of the first parity with genotype AA had 0.96 and 1.85 TNB more than those with genotypes AB and BB. The pigs of the first parity with genotypes AA and AB had 0.95 and 1.69 NBA more than those with genotype BB, respectively. For FSHb-2 locus, pigs of the first parity with genotype AA had1.57 and 2.15 TNB more than those with genotypes AB and BB. The pigs of the first parity with genotypes AA and AB had 1.00 and 0.94 NBA more than those with genotype BB, respectively. The pigs of multiparous with genotype AA had 0.25 kg of WB more than those with genotype BB. The results of combined genotype effects indicated that A allele of FSHb-1 locus in all the population and FSHb-2 locus in pigs of the first parity had the positive effective on TNB, NBA, and WB.