Abstract：Osteopontin (osteopontin, OPN) which is a secreted glycosylated phosphoprotein plays an important role mediated bone tissue and bone matrix during the connection process. For the purpose of enhancing the genetic progress and providing theoretical basis for marker-assisted selection (MAS) of production traits of milk goat, this research detected the osteopontin(OPN) gene polymorphisms of lactating ewe of milk goat(Capra hircus) in Laoshan by adopting the DNA pooling technology and high resolution melting curve analysis technology and analysed the association effect with milk and growth traits by adopting the generalized least squares. Two SNPs were detected among the 174 samples, one of which was the C/T represented by C/T which located at locus I355 of the fifth intron and the other was C/T represented by M/N which located at locus E341 of the seventh exon, whose polymorphism information content (PIC) were 0.2773 and 0.3267, respectively. The distribution of their allele and gene frequency was uneven in breeding farm (F) and breeding peasant (P), namely the Group P of locus I355 deviated from the equilibrium state of Hardy-Weinberg (P<0.05) and the rest was in the equilibrium state (P>0.05). During the analysis of association with lactation traits, the phenotypic values of all traits of Group P were extremely significantly (P<0.01) above those of Group F except for the conductance trait; as for the locus I355, the individual of genotype CC was significantly (P<0.05) above that of genotypes CT and TT in fat content. The traits of ash content and freezing point of genotype CC were significantly (P<0.05) above those of genotype CT. The allele N at locus E341 was the favorable allele of six traits such as non-fat material, lactose rate, milk density, milk protein rate, freezing point and ash content, and the difference of all traits was insignificant (P>0.05). During the analysis of association with growth traits, the body weight and body length of Group F were extremely significantly (P<0.01) above that of Group P; the rump width and rump length of Group P were extremely significantly (P<0.01) above that of Group F. As for the locus I355, the individual of genotype TT was extremely significantly (P<0.01) above that of genotype CC in body weight. As for the locus E341, the allele M was the favorable allele of the body height and bust; the individual of genotypes MM and MN was extremely significantly (P<0.01) above that of genotype NN in weight and rump width; the individual of genotype MM was extremely significantly (P<0.01) above that of genotype NN in the body length; the individual of genotype MM was significantly (P<0.05) above that of genotype NN in height and bust. Through this research, it is found that the OPN gene mutation locus I355 is related to the fat and carbohydrate contents in milk and the mutation locus E341 has significant association effect with the growth and development traits of milk goat, which therefore can be adopted for the molecular genetic markers of some growth traits of milk goat.
