Allele Frequency of c.486A G Polymorphism of the AA‐NAT Gene in Iranian Indigenous and Exotic Sheep Populations

Typically, lambing percentage is classified as a composite trait and is crucial to profitability in domestic sheep farming. In breeding programs, out-of-season reproduction of sheep is an important tool because seasonal reproduction limits productivity and flexibility. Understanding the complexities of genetic aspects of the none- seasonal reproduction has received significant critical attention in the literature. In this puzzle, the arylalkylamine-N-acetyltransferase (AA-NAT) is a rate-limiting enzyme of the melatonin synthesis pathway and is highlighted as a candidate gene that is responsible for melatonin synthesis and is thus di-rectly associated with out-of-season reproduction in sheep. With this scenario research, we aimed to exam-ine the allele frequency of the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) polymorphism in the AA-NAT gene in 11 native and exotic sheep populations. A total of 220 blood samples were taken from 11 breeds of sheep, including the exotic breeds Romanov (ROMV) and [Awassi (AWAS), Arabi (ARAB), Naaimi (NAIM) Iraqi native sheep] and [Ghezel (GHZL), Makui (MAKU)], Kurdi (KURD), Baluchi (BALCH), Afshari (AFSR) Iranian native sheep] and two Afshari-Booroola and Romanov-Ghezel F1 cross). Here, we describe the Smal-RFLP genotypes and allele frequency patterns of the (c.486A G) casual single nucleotide polymorphism (SNP) in the exon of AA-NAT within and between the examined sheep breeds. In addition, PCR sequencing methods were used to double-check A/G and con-firmation of PCR-RFLP results. This mutation changed the Arg Gly structure from helix to helix-effective in improving non-seasonal reproduction. Interestingly, the observed variation of G allele ranged from 0.1 to 0.43 in all study breeds. ROMV is a candidate for non-seasonal sheep breeds and its cross ex-presses the highest G allele frequency among other breeds studied. The frequency of the AA-NAT genotype was significantly different between breeds in this study. Therefore, the exotic 486A G mutation created a useful mirror to identify genomics aspects of seasonal/non-seasonal reproduction in sheep.