Association between AA-NAT gene polymorphism and reproductive performance in sheep

arylalkylamine n-acetyltransferase (aa-nat) is critical enzyme in melatonin (mlt) biosynthesis for mlt regulating the animal seasonal breeding. in this study, dna sequencing methods were applied to detect the polymorphisms of the aa-nat gene in 179 chinese sheep belonging to two non-seasonal reproduction breeds and two seasonal reproduction breeds. one mutation at exon 3 (nm_001009461:c.486a > g) was ？rstly described at the sheep aa-nat locus. hence, we described the smai pcr-rflp method for detecting ex3 486a > g mutation, frequencies of the aa-nat-g allele varied from 0.871 to 0.908 in two non-seasonal reproduction breeds and 0.517 to 0.578 in two seasonal reproduction breeds. the associations of smai polymorphism with estrus traits was analyzed in non-seasonal reproduction breeds sheep and seasonal reproduction breeds sheep, the signi？cant statistical results were found between them, the gg genotype frequencies was higher in non-seasonal reproduction breeds (p < 0.001), while, the ga genotype frequencies was higher in seasonal reproduction breeds (p < 0.05). hence, the ex3 486a > g mutation could facilitate association analysis and serve as a genetic marker for chinese sheep breeding and genetics.