Analysis of polymorphism of melatonin receptor type 1A (MTNR1A)‎ gene, in Iraqi local sheep using PCR-RFLP technique

Abstract EN

The gene encoding melatonin receptor type 1A (MTNR1A) gene by PCR-RFLP, the aim of the present study of polymorphism MTNR1A gene associated with breeding out of season and correlated with prolactin hormone in Iraqi sheep breed,.

Blood samples were randomly collected from 60 ewes from Agriculture Research-Ruminant Researches station breeding station, Baghdad, and genomic DNA was isolated using a Geneius TM Micro gDNA Extraction Kit.

A large fragment of exon 2 of MTNR1A gene was amplified by PCR using specific primer pairs and the PCR product was digested with RsaI enzyme which cuts the amplicon to several fragments.

There are four cleavage sites (53 bp, 267 bp, 23 bp, 411 bp, 70 bp) for Rsa I within the amplification fragment, Digestion with Rsa1yielded polymorphic fragments of 267 bp when the cleavage site was present (allele R) and a single 290 bp fragment when the cleavage site was (allele r).

Three genotypes RR (411 bp/267 bp), Rr (411/290 bp/267 bp) and rr (411 bp/290 bp).

Three fragments of 23bp, 53 bp and 70bp were been not related allelic polymorphism .Restricted digestion allowed the determination of two alleles (R, r), Result gene frequencies were 0.40 and 0.60 for the alleles R and r respectively, in local ewes and genotype frequencies of RR (20%), Rr (40%) and rr (40%) in ewes with a significant at (P<0.01), the level of prolactin relation to the genotype differences that the highest hormonal level linked to the RR genotype (234.65±17,48ng/ml), and high significant (P<0.01) with lower values for prolactin hormone that linked to Rr and rr genotype (217.

02 ± 28.12; 182.91 ± 21.35 ng/ml) in local Iraqi ewes and no-significant values between the out and the in season lambing months, however, higher significant variation (P<0.01) of frequencies of R genotype (62.50%) in out-seasonal lambing months than in-seasonal lambing months (37.50%).

It was concluded that the alleles frequencies of MTNR1A gene ‘r’ higher than ‘R’ alleles, Analysis of the MTNR1A polymorphism its relationship with prolactin concentration of Moreover show the indirect effect of higher prolactin concentration with genotype RR of the MTNR1A gene polymorphism and can be used a genetic selection marker for spring (out-of-season) breeding in Iraqi local sheep.