Genetic Polymorphism of Melatonin Receptor (MTNR1A) Gene in Populations of Local Sheep Breeds

Deana Gencheva

Abstract: In the present study the single nucleotide polymorphism in exon II of the melatonin receptor (MTNR1A) gene was investigated on a total of 177 individuals representing four local (autochthonous) Bulgarian sheep breeds: Copper-red Shumen, Karakachan, Pleven Blackhead and Sofia (Elin-Pelin). Two genetic variants of MTNR1A gene (C and T) and three genotypes (CC, CT and TT) have been identified using PCR-RFLP analysis. The obtained gene frequencies of MTNR1A C and T in two investigated sheep breeds, were contrary: 0.694 and 0.306 in Pleven Blackhead sheep, versus 0.267 and 0.733 in Copper-red Shumen sheep, respectively. Similar allele C/T frequencies were found in the other sheep breed: 0.589 for and 0.411 in Karakachan and 0.605 and 0.395 in Sofia sheep, respectively. The genetic diversity at MTNR1A gene was with the highest value in Sofia sheep population (Ho = 0.512 и He = 0.489), low coefficient of inbreeding (Fis = -0.070) and in correspondence with HWE equilibrium (P = 0.701). An average level of genetic diversity was established in the populations Copper-red Shumen, Karakachan and Pleven Blackhead (He = 0.391, 0.489 and 0.428), high coefficient of inbreeding (Fis = 0.432, 0.495, 0.258) and HWE deviation (P = 0.002, 0.006 and 0.049). The highest Nei’s genetic distance (DA = 0.369) was established between Copper-red Shumen and Pleven Blackhead sheep populations, whereas the lowest (DA = 0.005) - between Karakachan and Sofia sheep. The results presented in this study showed clearly polymorphism in exon II of the ovine MTNR1A gene with respect to Bulgarian local sheep breeds and therefore would be confirm the importance of this polymorphism as a potential DNA marker in marker - assisted selection (MAS), as well as for preservation genetic diversity of the examined sheep populations.

Keywords: Melatonin receptor gene (MTNR1A); Ovis aries; PCR-RFLP analysis; Single nucleotide polymorphism (SNP)

Date published: 2019-05-09