Document Type : Research Paper

Authors

• Neda Saba ¹
• Rahimeh Sepehri ²
• Taher Harkinezhad ¹

¹ Department of Animal Science, Faculty of agriculture, University of Zanjan, Zanjan, Iran.

² Department of Animal Science, Faculty of agriculture, University of Zanjan. Zanjan , Iran.

Abstract

The reproduction of most breeds of sheep, especially the Iranian breeds, is seasonal. The hormone melatonin plays an important role in seasonal reproduction. The purpose of this research was to examine the polymorphism(s) in exon two of the MTNR1A gene in Afshari sheep in two groups of random and non-seasonal samples (35 randomly selected ewes and 44 spring calving ewes). After extracting DNA from blood samples and designing specific primers, the target DNA was amplified by the PCR method. Based on the results of the sequence analysis in some samples, a polymorphism at nucleotide 408 of the amplified fragment was identified (corresponding to the C519C>T polymorphism of the cDNA sequence). Genotype identification of non-sequenced samples was performed by PCR-RFLP. All three genotypes of this SNP: CC, CT and TT with frequencies of 0.78, 0.1 and 0.06, respectively, were observed. The frequency of the C allele (0.835) was higher than that of the mutant allele. However T allele had a higher frequency in the non-seasonal group. In addition, a positive and significant correlation between genotype and seasonal reproduction was observed (r=0.36, p-value=0.0001). Analysis of the odd ratios also showed that the T allele was 19 times more likely to occur in the non-seasonal group than in the random group. In general, it appears that the T allele in this position correlates with non-seasonal reproduction in sheep. If this results can be confirmed in further studies, the mentioned polymorphism can be used in breeding schemes to improve the reproductive status of sheep.

Keywords

• Afshari sheep
• melatonin
• Exon2
• non-seasonal reproduction
• SNP

Main Subjects

• Genetics