Abstract：Abstract The polymorphisms of pituitary adenylate cyclase-activating polypeptide gene(PACAP) were detected in a 257 Qinchuan cattles(Bos tarurs) population by using PCR-SSCP and the assocation of genotype with partial growth traits was calculated by the least squire method(LSM). Result showed that a G/A mutation was found at the locus of 3909 bp, which result in 3 genotypes named AA,AB and BB respectively. Allele frequencies of A and B were 0.5992 and 0.4008, respectively. χ2 test showed that the locus was in Hardy-Weinberg equlibrium in the Qinchuan cattle population detected. Variance analysis showed: The body length of individuals with AA, AB and BB genetype were extremely significantly difference ( P<0.01); The wither height of individuals with AA and AB genotype was extremely significantly higher than those with BB (P<0.01), and those with AA genotype was significantly higher than those with AB ( P<0.05); The body weight of individuals with AA and AB genotype was extremely significantly higher than those with BB (P<0.01); The heart girth of individuals with AA genotype was extremely significantly higher than those with BB (P<0.01), those with AA genotype was significantly higher than those with AB genotype(P<0.05), and those with AB genotype was significantly higher than those with BB genotype( P<0.05); The heart width of individuals with AB genotype was significantly higher than those with BB ( P< 0.05); There were not significantly differences in the other growth traits among individuals with different genotypes. The locus can be a potential QTN affecting body length, wither height, body weight, heart girth and heart width or tightly linked with it. It will be a candidate moleculer marker for the Qinchuan cattle breeding.
