Association between Melatonin Receptor 1A (MTNR1A) Gene Polymorphism at the MnlI Site and Production Traits in Shal and Crossbreeding between Shal and Romanov

The objective of this study was to evaluate the relationship between polymorphism at the MnlI site of MTNR1A gene and production traits of Shal and Romanov crossbreeding. The crossbreeding between Shal and Romanov was done on 600 Shal ewes. For this reason, Shal ewes were laparoscopically and artificially inseminated with the semen of Romanov breed. For the preparation of genomic DNA, a total of 90 ewes, either Shal (n=50) or Shal × Romanov (n=40), were used and an 824 bp fragment of exon 2 of the MTNR1A gene was amplified. In this research, two genotypes MM and Mm were detected in the study Shal popula-tion with frequencies of 0.78 and 0.22, respectively, while MM and mm genotypes of the study crossbreeds were detected with 0.125 and 0.0875 frequencies, respectively. However, the mm and Mm genotypes were not detected in Shal and Shal × Romanov crossbreeds, respectively. The MnlI marker site in Shal × Ro-manov breeds had a significant effect (P>0.05) on body weight after 3 months (BW3) as the ewes with MM genotypes had significantly higher BW3 than mm individuals. However, no significant difference was ob-served between MM and mm marker sites for birth weight (BW) and 6-month body weight (BW6). The same results were observed for Shal breeds as when MM and Mm genotypes were detected for BW, BW3 and BW6 traits. In conclusion, in this study, mm genotype as a measurement for litter size in sheep breeds was successfully introduced into Shal × Romanov crossbreeds, while their production traits were not af-fected by MnlI genotypes.