The combined genotypes effect of ESR and FSH beta genes on litter size traits in five different pig breeds

Estrogen receptor (ESR) and Follicular-stimulating hormone beta subunit (FS H beta) genes were chosen as candidates to determine whether they control l itter size and some other reproductive traits in swine. 269 sows from five different pig breeds were genotyped by an established PCR-RFLPs protocol at both ESR and FSH beta loci. The effects of both ESR and FSH beta on pig re productive traits, including total number born (TNB) and number born alive (NBA), are analyzed by SAS software (version 6.12), These computation resul ts demonstrated that both ESR locus and FSH beta locus are the major genes influencing litter size in pigs. The sows of BBBB combined genotype of ESR and FSH beta loci generally produce 1.85-3.01 TNB and 2.0-3.0 NEA more than those of ABAA combined genotype. The notable effect of ESR locus and FSH b eta locus on litter size of pigs have made it possible to improve the pig r eproduction by Marker-assisted selection (MAS), Moreover, introgression of the beneficial alleles into commercial pig breeding lines, in which the all eles were not present, will improve greatly the economically important repr oductive traits and efficiency of pig production.