Polymorphisms Of RBP4, RARG, MYOG Genes And Their Relationships With Reproduction Performance Of Sows

The reproductive trait of swine is a low heritance quantitative trait (h2=0.1),in conventional method to improve this trait almost have no sign effect. With development of molecular genetics and technology, the high hopes on action of the major genes or genetic markers.Since the 1980's, some candidate genes about litter size trait had been found,had provided the conditions about the marker-assisted for the reproductive traits.Vitamin A(VA)is necessary to promote sperm and ovum creation,placenta development and fetus growth.VA can improve the synchronization of embryonic development, reducing the mortality of early embryos, can improve uniformity of newborn piglets.VA also can adjust the content of progesterone in the blood, thus affecting the reproductive performance of sows. Skeletal muscle fiber is constitute the basic unit of skeletal muscle, Its production is limited to embryonic stage.In pig fetal about 70 days already formed, So the development of muscle fiber of embryonic stage can effect performance of litter weight born and body weight uniformity of piglets born.In the project, SNPs of RBP4 gene, RARG gene and MYOG gene were detected in Minpigs, Landrace,Yorkshire,Duroc and cross-breed populations (in totle number are 458)by Sequencing,PCR-SSCP and PCR-RFLP, in the meantime, the distribution for genotypes frequencies and alleles frequencies of these SNPs in different populations and their effects on reproduction performance were studied. The results as follows:(1)The genotypes frequencies and alleles frequencies of RBP4 gene MSPⅠsite is significantly different in different populations. Minpigs with AA genotype had higher litter size,number of piglets surviving to day 21 and number of piglets surviving to weaning.With the results of other populations, RBP4 gene MSPⅠsite AA genotype promote number of litter siz of sows.(2) One polymorphism locus which resulted in a change of amino acid (A→G) in RARG gene intron 3was detecetd in partial coding sequence of RARG gene.The genotypes frequencies and alleles frequencies of RARG gene intron 3 site is significantly different in different populations.Minpigs of AA genotype had better uniformity at 21 days and better body weight uniformity of piglets on weaning than Minpigs with BB genotype,Yorkshire sows with AA genotype had higher number born alive and heavier litter weight born than BB genotype sows,but have no sign effect on the other populations of reproductive performance.So can't judge the effect on the litter size of sows.(3) In different populations, The genotypes frequencies of BBBB of RBP4 gene and RARG gene incorporate genotypes is lowest. Different incorporate genotypes of RBP4 and RARG gene have different effects on reproductive performance of Minpigs, Landrace and Yorkshire populations,but have no significant role,indicate that two genes have extremely complex interaction.(4) The genotypes frequencies and alleles frequencies of MYOG gene intron 2 site, 3'side site and 5'side site were no significant different in different populations. Minpigs with MYOG gene intron 2 AA genotypes had higher number of piglets surviving to day 21 and number of piglets surviving to day weaning than Minpigs with BB genotypes, but Minpigs with AB genotypes had lower weight of piglets on day 21 than Minpigs with AA and BB genotypes.As regards Landrace, sows with AA genotypes had lower total number born and number born alive than sows with BB genotypes.As regards Yorkshire, sows with BB genotypes had higher total number born,number born alive and number of piglets surviving to day 21 than sows with AA genotypes,but sows with AA genotypes had better body weight uniformity of piglets born than sows with BB genotypes.With result of Landrace and Yorkshire,BB genotype promote the number of litter size of sows; For MYOG gene 3'side site, AS regards Landrace, sows with AA genotypes had heavier litter weight born than sows with BB genotypes.As regards Yorkshire, sows with AA genotypes had heavier litter weight born than sows with BB genotypes.As regards Duroc, sows with AA genotypes had higher number born alive than sows with BB genotypes.the result of project show that AA genotypes can promote the number of litter size; For MYOG gene 5'side site, Minpigs with AA genotypes had higher total number born than sows with BB genotypes,but had no effects on the other populations,so should do futher research to definite MYOG gene 5'site effects on reproductive performance.