Melatonin Receptor 1A Gene Research Articles

Melatonin suppresses milk fat synthesis by inhibiting the mTOR signaling pathway via the MT1 receptor in bovine mammary epithelial cells.

Milk fat content is an important criterion for assessing milk quality and is one of the main target traits of dairy cattle breeding. Recent studies have shown the importance of melatonin in regulating lipid metabolism, but the potential effects of melatonin on milk fat synthesis in bovine mammary epithelial cells (BMECs) remain unclear. Here, we showed that melatonin supplementation at 10μmol/L significantly downregulated the mRNA expression of lipid metabolism-related genes and resulted in lower lipid droplet formation and triglyceride accumulation. Moreover, melatonin significantly upregulated melatonin receptor subtype melatonin receptor 1a (MT1) gene expression, and the negative effects of melatonin on milk fat synthesis were reversed by treatment with the nonselective MT1/melatonin receptor subtype melatonin receptor 1b (MT2) antagonist. However, a selective MT2 antagonist did not modify the negative effects of melatonin on milk fat synthesis. In addition, KEGG analysis revealed that melatonin inhibition of milk fat synthesis may occur via the mTOR signaling pathway. Further analysis revealed that melatonin significantly suppressed the activation of the mTOR pathway by restricting the phosphorylation of mTOR, 4E-BP1, and p70S6K, and the inhibition of melatonin on milk fat synthesis was reversed by mTOR activator MHY1485 in BMECs. Furthermore, in vivo experiments in Holstein dairy cows showed that exogenous melatonin significantly decreased milk fat concentration. Our data from in vitro and in vivo studies revealed that melatonin suppresses milk fat synthesis by inhibiting the mTOR signaling pathway via the MT1 receptor in BMECs. These findings lay a foundation to identify a new potential means for melatonin to modulate the fat content of raw milk in Holstein dairy cows.

Melatonin receptor 1A (MTNR1A) gene polymorphisms in the local goat population in South Sulawesi region of Indonesia

Some important genes are involved in controlling the reproductive trait of goats, one of which is the Melatonin Receptor 1A (MTNR1A) gene. The MTNR1A gene is known with seasonal reproductive activity and related to lambing frequency in the goat. The purpose of this research was to determine the genetic polymorphisms of the MTNR1A gene in Kacang, and Peranakan Ottawa (PE) goat population reared traditionally in South Sulawesi region of Indonesia. In total 253 heads of goat consist of 137 heads of Kacang and 116 Peranakan Ottawa from South, Sulawesi region was used as research samples for blood collection. The blood samples were collected from the jugular vein, which was then continued for DNA extracted by using a DNA extraction kit. The MTNR1A genotype was identified by PCR-RFLP technique using restriction enzyme RsaI. The result showed that there was genetic diversity in the MTNR1A gene in Kacang and PE population with the obtained of two alleles R and r. The common allele was R with frequency 0.93 in Kacang population while in PE population was 0.89. The r allele was 0.06 and 0.10 in Kacang and PE population, respectively. The most common genotype found in the population was RR (0.95), while Rr was only 0.05 and rr genotype did not found in this population. Observed heterozygosity value was 0.05. According to the Hardy-Weinberg test, this population was in equilibrium for MTNR1A gene. In conclusion, this finding indicated that there was genetic diversity exists in local goat population, and future research needed to find any association with this genetic variation with reproductive performance, the data obtained from this study could be used for the strategic program in goat breeding to increase reproductive performance of local goat especially fertility traits.

No polymorphism of melatonin receptor 1A (MTNR1A) gene was found in Markhoz goat.

Melatonin is the main hormone of seasonal breeding in sheep and goat which has an effect on reproductive organs via its receptors. Studies have shown that mutations in melatonin receptor 1A (MTNR1A) gene are related to litter size as well as the ovulation rate in sheep and goats. In this study, polymorphism of two loci in MTNR1A melatonin receptor gene was studied in order to survey their relationship with litter size in Markhoz goats. PCR primers were employed to mask polymorphisms of MTNR1A in 150 does by PCR‐RFLP method. After DNA extraction, the PCR‐RFLP was performed using Ecol31I and HpaI restriction enzymes. Results showed that these loci were not polymorphic. These results show that the fecundity of Markhoz goats is not linked to MTNR1A. No polymorphism in MTNR1A was found in Markhoz goats, therefore, it is essential to test polymorphism of other genes or loci to facilitate marker‐assisted selection techniques to improve reproduction traits in Markhoz goats.

Association of MTNR1A and CYP19 genes polymorphisms with sperm quality and testicular size in Sanjabi breed rams

Abstract The purpose of this study was to identify mutations in melatonin receptor 1A (MTNR1A) and aromatase cytochrome P450 (CYP19) genes using PCR-RFLP technique and their associations with sperm quality and testicular size traits in Sanjabi breed rams. The blood and sperm samples were collected from Sanjabi rams (n = 96). Genomic DNA was extracted from the blood. A 824bp fragment from exon II of MTNR1A gene and a 517bp fragment from promoter 2 (P2) of CYP19 gene were amplified using two pairs of specific primers. The PCR products were separately digested by two restriction enzymes, SsiI for MTNR1A locus and DraI for CYP19 locus. Digestion by SsiI restriction enzyme resulted in CC, CA and AA genotypes with frequency of 0.45, 0.41 and 0.14, respectively. However, digestion of 517bp fragment of CYP19 gene by DraI endonuclease determined two AG and AA genotypes with frequency 0.89 and 0.11, respectively. The Chi-square test proved that the two loci were in Hardy-Weinberg equilibrium (HWE). The significant effect was observed between different genotypes of MTNR1A gene and morphological trait (P<0.05) and there was a significant association between different genotypes of CYP19 gene and scrotal circumference trait (P<0.05). The results of this study indicated that polymorphisms of MTNR1A and CYP19 genes were not associated with most traits of sperm quality and testicular sizes. Therefore, it seems that further studies are needed to identify mutations in other regions of these genes and other genes responsible to genomic regions for the sperm quality and testicular size in Sanjabi ram in order to improve fertility in these herds.

Polymorphism of the STAT5A, MTNR1A and TNFα genes and their effect on dairy production in Bubalus bubalis

The water buffalo is a fundamental resource, especially in developing countries, however, differently from other species, its genetic potential is still poorly investigated. In this work, we performed a candidate gene association study for milk composition in 491 female buffaloes. Animals were from four farms located in Southern Italy, where the Out-of-Breeding-Season-Mating technique is usually performed. We analysed three genes: (1) the signal transducer and activator of transcription 5A (STAT5A), (2) the tumour necrosis factor alpha (TNFα) and (3) the melatonin receptor 1A (MTNR1A). We confirmed the mutation at the MTNR1A gene and we found five novel single nucleotide polymorphisms (SNPs): one in the TNFα and four in the STAT5A. No associations were found for the SNPs in the MTNR1A and TNFα genes, while we identified a marked association with milk protein % for a C > T substitution at the STAT5A gene. At this locus, the TT buffaloes showed significantly higher protein percentage in milk. Conversely, this genotype class was the less frequent in the population. Moreover, an A > G substitution at the STAT5A showed an influence on reproductive seasonality, with the advantageous allele most frequent in the population, suggesting a possible effect of selection for this trait. The C > T substitution on STAT5A detected in present study could be used in marker assisted selection of Mediterranean Italian buffalo, and should be monitored to understand the reasons behind the low frequency of the favourable genotype at this locus and to stop this unfavourable trend in the population.

Common Genetic Variation Near Melatonin Receptor 1A Gene Linked to Job-Related Exhaustion in Shift Workers.

Study Objectives:Tolerance to shift work varies; only some shift workers suffer from disturbed sleep, fatigue, and job-related exhaustion. Our aim was to explore molecular genetic risk factors for intolerance to shift work.Methods:We assessed intolerance to shift work with job-related exhaustion symptoms in shift workers using the emotional exhaustion subscale of the Maslach Burnout Inventory-General Survey, and carried out a genome-wide association study (GWAS) using Illumina’s Human610-Quad BeadChip (n = 176). The most significant findings were further studied in three groups of Finnish shift workers (n = 577). We assessed methylation in blood cells with the Illumina HumanMethylation450K BeadChip, and examined gene expression levels in the publicly available eGWAS Mayo data.Results:The second strongest signal identified in the GWAS (p = 2.3 × 10E-6) was replicated in two of the replication studies with p < .05 (p = 2.0 × 10E-4 when combining the replication studies) and indicated an association of job-related exhaustion in shift workers with rs12506228, located downstream of the melatonin receptor 1A gene (MTNR1A). The risk allele was also associated with reduced in silico gene expression levels of MTNR1A in brain tissue and suggestively associated with changes in DNA methylation in the 5' regulatory region of MTNR1A.Conclusions:These findings suggest that a variant near MTNR1A may be associated with job-related exhaustion in shift workers. The risk variant may exert its effect via epigenetic mechanisms, potentially leading to reduced melatonin signaling in the brain. These results could indicate a link between melatonin signaling, a key circadian regulatory mechanism, and tolerance to shift work.

Association of single nucleotide polymorphism in melatonin receptor 1A gene with egg production traits in Yangzhou geese.

In the present study the melatonin receptor 1A gene (MTNR1A) was proposed to be a candidate gene for egg production in Yangzhou geese. A total of 210 goose blood samples were collected to investigate the association of the MTNR1A gene with the number of eggs produced. Using a direct sequencing method, a single nucleotide polymorphism (SNP; g.177G>C) was detected in the 5' regulatory region of the MTNR1A gene (Genbank ss1985399687). Two alleles (G and C) and three genotypes were identified. Association analysis results showed that the g.177G>C SNP significantly affected the level of egg production within a 34-week egg-laying period (P<0.05). Furthermore, the geese with the GG genotype produced significantly more eggs compared to the geese with the CC genotype. Quantitative real-time PCR analysis showed that the MTNR1A gene was highly expressed in small intestine, granulosa cell and ovary compared to other examined tissues. In addition, the mRNA expression level of MTNR1A in ovary indicated that significantly higher expression levels were recorded for geese with the GG genotype compared to those with the CC genotype. Moreover, a luciferase reporter assay showed that the CC genotype had significantly lower promoter activity than did GG. These results suggest that the identified SNP in the MTNR1A gene may influence the number of eggs produced and mRNA expression levels in Yangzhou geese and could be considered as a useful molecular marker in goose selection and improvement, especially for egg production.

Polymorphism of the melatonin receptor 1A (MNTR1A) gene and association with seasonality of reproductive activity in a local Greek sheep breed.

BackgroundSheep’s reproductive physiology in temperate latitudes (such as Greece), is characterized by seasonality and is also regulated by photoperiodic exposure. Melatonin is the key hormone involved in this regulation. However, the melatonin secretion and therefore the ewes reproductive activity underlies variation, proposed to be linked with the melatonin receptor subtype 1A (MNTR1A) gene structure. This study was designed to investigate the polymorphism of the MNTR1A gene in a local Greek sheep breed and to determine its potential association with reproductive seasonality.ResultsTwo groups of farmed ewes, each consisted of 30 individuals, were chosen. Males were introduced in both groups in spring (April). The first group consisted of ewes that showed reproductive activity in spring (May), while the second of ewes that showed reproductive activity 3 months later, in summer. The PCR–RFLP methodology was carried out on a 824-bp DNA fragment of the MTNR1A exon 2 using the RsaI restriction endonuclease. The electrophoretic procedure revealed three genotypes, C/C, C/T and T/T. Specifically, 44 animals showed the C/C genotype (28 from the first group and 16 from the second), 14 the C/T genotype (2 from the first and 12 from the second) and 2 animals had the T/T genotype (both from the second group).ConclusionsStatistical analysis indicated a positive correlation between genotype and reproductive seasonality, with C/C genotype playing a crucial role in out-of-season reproduction activity.

DNA methylation within melatonin receptor 1A (MTNR1A) mediates paternally transmitted genetic variant effect on asthma plus rhinitis

Asthma and allergic rhinitis (AR) are common allergic comorbidities with a strong genetic component in which epigenetic mechanisms might be involved. We aimed to identify novel risk loci for asthma and AR while accounting for parent-of-origin effect. We performed a series of genetic analyses, taking into account the parent-of-origin effect in families ascertained through asthma: (1) genome-wide linkage scan of asthma and AR in 615 European families, (2) association analysis with 1233 single nucleotide polymorphisms (SNPs) covering the significant linkage region in 162 French Epidemiological Study on the Genetics and Environment of Asthma families with replication in 154 Canadian Saguenay-Lac-Saint-Jean asthma study families, and (3) association analysis of disease and significant SNPs with DNA methylation (DNAm) at CpG sites in 40 Saguenay-Lac-Saint-Jean asthma study families. We detected a significant paternal linkage of the 4q35 region to asthma and allergic rhinitis comorbidity (AAR; P=7.2×10(-5)). Association analysis in this region showed strong evidence for the effect of the paternally inherited G allele of rs10009104 on AAR (P=1.1×10(-5), reaching the multiple-testing corrected threshold). This paternally inherited allele was also significantly associated with DNAm levels at the cg02303933 site (P=1.7×10(-4)). Differential DNAm at this site was found to mediate the identified SNP-AAR association. By integrating genetic and epigenetic data, we identified that a differentially methylated CpG site within the melatonin receptor 1A (MTNR1A) gene mediates the effect of a paternally transmitted genetic variant on the comorbidity of asthma and AR. This study provides a novel insight into the role of epigenetic mechanisms in patients with allergic respiratory diseases.

Identification of Genetic Variation of Melatonin Receptor 1A (MTNR1A) Gene in Kıvırcık Breed Ewes by MnlI and RsaI Restriction Enzymes

Melatonin receptor 1A (MTNR1A) gene encodes melatonin hormone which regulates the function of seasonal reproductive activity in sheep. The aim of this study was to make the genetic characterization and identify the variant alleles of MTNR1A gene in Kivircik breed. Blood samples of 110 Kivircik sheep were collected from five different farms located in Kirklareli and Istanbul. DNA extraction was performed from blood samples. Exon 2, the polymorphic region of Melatonin receptor 1A gene, was amplified and PCR products were genotyped by using MnlI and RsaI enzymes. The observed alleles and genotypes for MnlI enzyme were; M (0.891), m (0.109) and MM (0.782), Mm (0.218) respectively. Kivircik sheep was null from mm genotype. Also identified alleles were C (0.682), T (0.318) and genotypes were CC (0.582), CT (0.200), TT (0.218) for RsaI enzyme. The most frequent genotypes were MM (78%) and CC (58%) in Kivircik ewes. Since MM and CC genotypes were known with their positive effect on out of season reproductive activities, Kivircik ewes with these genotypes might suggested to be used in out of season lambing when demanded.

Novel polymorphism in exon 1 of the melatonin receptor gene unassociated with reproductive characteristics of buffaloes in the Amazon Region.

The objective of this study was to sequence part of the exon 1 in the melatonin receptor 1A gene (MTRN1A) in buffaloes to detect a novel polymorphism with which to associate reproductive characteristics, such as age at first birth and the interval between births, in buffaloes from the northeastern region of the State of Pará (Brazil). Buffalo hair samples (77) were collected from the Terra Firme region of Pará. DNA was extracted and polymerase chain reactions (PCRs) were carried out with a primer that was designed using the GenBank accession No. AY524665 reference sequence. PCR products were purified and sequenced. After editing and analysis of the sequences, a mutation was observed at the 62nd position in exon 1 of MTRN1A (T↔C), which corresponded with a change in the 21st amino acid from leucine to proline. All possible genotypes were observed, with the most common being genotype CC (0.481). The allele frequencies were T = 0.377 and C = 0.623. Statistical analysis of FIS showed inbreeding within the sample group (FIS = 0.397) and deviations from the Hardy- Weinberg equilibrium were observed (P < 0.05). Associations between genotypes and reproductive characteristics were not significant (P > 0.05). Although the related SNP was not synonymous, there were no observable effects on the reproductive characteristics under investigation. As such, it would be ideal to detect other SNPs in exon 1 of the MTRN1A gene that can be associated with reproductive characteristics in Amazonian buffaloes.

Association study and expression analysis of MTNR1A as a candidate gene for body measurement and meat quality traits in Qinchuan cattle

Melatonin receptors, which mediate the functions of melatonin, play an important role in adipocyte differentiation, energy, and lipid metabolism. The aim of this study was to identify single nucleotide polymorphisms (SNPs) in bovine melatonin receptor 1A (MTNR1A) and to determine if these SNPs are associated with body measurement traits (BMTs) and meat quality traits (MQTs) in Qinchuan cattle. We identified three synonymous mutations (A455G, A497G, and C635T) and one missense mutation (G489A) p.Asp224Asn in MTNR1A gene in 420 Qinchuan cattle by sequencing. Association analysis indicated that these four SNPs were associated with some of the BMTs and MQTs (P<0.05). Further, 6 combined haplotypes were constructed to guarantee the reliability of analysis results. Individuals with diplotypes H2H2 (AA-GG-GG-CC) had greater chest depth, heart girth, loin muscle area, and more back fat than the other combinations (P<0.05). Pertaining to G489A mutation, RT-PCR study exhibited a higher mRNA expression of MTNR1A gene among individuals with SNP1/2/4-AG-GA-CT genotype than those with SNP1/2/4-AA-GG-CC genotype (P<0.05). These results suggest that the genotype H2H2 could be used as a molecular marker of the combined genotype for future selection for BMTs and MQTs in Qinchuan cattle.

Melatonin Receptor 1A (MTNR1A) gene sequence characterization and SNP identification in Tropical sheep breeds of India

Sheep is considered to be short day seasonal breeder. Sheep does show varying behavior in terms of seasonal reproduction between temperate and tropical latitudinal regions. MTNR1A gene has been studied widely for being linked to seasonality in sheep. Recently, through our studies we have characterized the MTNR1A gene in Tropical arid sheep breeds and could find out that the GG and CC genotypes are having higher prevalence in the tropical arid breed populationwith reference to two SNP markers ‘ ‘G612A’ and C606T’ respectively.

Melatonin receptor 1A gene RsaI and inhibin alpha subunit gene HaeII polymorphisms in Honamli and Hair goat breeds reared in Western Mediterranean region of Turkey

The melatonin receptor 1A (MTNR1A) and inhibin alpha subunit (INHA) genes play a significant role in the reproductive characteristics of animals. Blood samples were collected from 371 goats (Honamli and Hair) reared in Antalya and Burdur. The polymerase chain reaction (PCR) products were digested by RsaI for the MTNR1A gene and HaeII for the INHA gene. Two alleles (A and G) and three genotypes (AA, AG, and GG) were observed for the INHA gene, while two alleles (R and r) and two genotypes (RR and Rr) were observed for the MTNR1A gene. The highest allelic frequency value for G (91.8%) was found in Honamli goat breeds for the INHA gene while the highest value for R (98.1%) was found in Hair goat breeds for the MTNR1A gene. The GG genotype for the INHA gene and the RR genotype for the MTNR1A gene were identified as the most common genotypes of the Honamli and Hair goat breeds. The rr genotype for the MTNR1A gene could not be determined in the breeds. Both Honamli and Hair goat breeds were in Hardy–Weinberg equilibrium for the genes that were studied. In conclusion, this study confirms the existence of genetic polymorphism in the MTNR1A and INHA genes as detected by PCR-RFLP analysis in Honamli and Hair goat breeds.

The relationship between melatonin receptor 1A gene (MTNR1A) polymorphism and reproductive performance in Sarda breed sheep

In several species the circadian changes in melatonin secretion acts as the organic informer of the photoperiodic trend. Some physiological functions, such as reproduction, are influenced by seasonal melatonin secretion. In small ruminants polymorphisms at the MTNR1A gene are associated with non-seasonal breeding. The aim of this research was to evaluate if the MTNR1A gene polymorphism influences first conception, second and third lambing in Sarda breed sheep. Two-hundred ewe lambs, born between 10th November and 10th December 2008, were randomly chosen from four selected farms and genotyped for the A612G polymorphism at the MTNR1A gene. To rule out a possible confounding effect of the low frequency of the A/A genotype in Sarda sheep, 800 ewe lambs were genotyped and 85 individuals were selected for each genotype (A/A, A/G and G/G). Fertile rams were given access to the selected ewe lambs from 30th July to 30th October 2009 during the first year, and from 1st May to 30th October 2010 and 2011 on the second and third year, respectively. Mating and lambing dates were recorded for each ewe during the three years. In the first year ewe lambs showed no differences among genotypes in their fertility rates, litter size and mean number of days from ram introduction to parturition. However, in the second and third year G/G and A/G genotypes showed, a shorter interval (expressed in days) from ram introduction to lambing, compared to A/A genotype (P<0.05). During the second year fertility rate for the G/G, A/G and A/A genotypes, were 91.7%, 90.2% and 89.9%, respectively; whereas in the third year fertility rates were 91.5% for G/G, 91.8% for A/G and 93.0% for A/A genotypes. We speculate that the similarity in fertility rates among different genotypes may be due to a carry-over effect because ew\\es carrying different genotypes were not separated. Results indicate that the MTNR1A gene polymorphism does not influence the onset of reproductive activity in Sarda ewe lambs, but this single nucleotide polymorphism (SNP) reveals its influence in the earlier reproductive resumption in the adult ewes. The interval from rams׳ introduction to lambing may be longer if animals with different genotypes were kept separated.

Influences of melatonin treatment, melatonin receptor 1A (MTNR1A) and kisspeptin (KiSS-1) gene polymorphisms on first conception in Sarda ewe lambs.

In order to investigate if the melatonin receptor 1A (MTNR1A) and kisspeptin (KiSS-1) genes influence the reproductive response to melatonin treatment, 510 Sarda ewe lambs were divided into groups C (control) and M; Group M received one melatonin implant (18mg). After 35 days rams were introduced for 40 days and subsequent lambing dates and number of newborns were recorded. The MTNR1A gene Exon II and KiSS-1 gene Exon I were amplified and genotyped by restriction fragment length polymorphism (RFLP) and single-strand conformation polymorphism analysis. Two single nucleotide polymorphisms (SNPs; C606T and G612A) in MTNR1A and one (G1035A) in KiSS-1 were found. The most frequent genotypes were G/G (63%) and C/C (53%) for MTNR1A and G/G (92%) for KiSS-1. Treated animals showed a higher lambing rate (P<0.05) and an advanced lambing date (P<0.05) compared with controls. The three SNPs did not influence the onset of reproductive activity. The majority of the G/G animals of Group M lambed before 190 days after ram introduction (P<0.05), while in Group C a higher number of G/G animals lambed after this date. Data revealed the positive effect of melatonin treatment on the time of first conception in ewe lambs and highlighted that the G/G genotype of the MTNR1A gene is able to influence the reproductive response to melatonin treatment.

Influence of melatonin receptor 1A gene polymorphisms on seasonal reproduction in Sarda ewes with different body condition scores and ages

In several species, circadian changes in melatonin concentrations play a key role in the photoperiodic control of seasonality. In sheep, two silent mutations in the melatonin receptor 1A gene (MTNR1A) at positions 606 and 612 of the exon II are associated with seasonal reproduction. However, in some sheep breeds, no relationships have been found between MTNR1A polymorphisms and reproductive seasonality. This lack of relationship could be due to effects of breed, body condition, age, and/or environmental conditions. Thus, the present study was conducted with the Sarda sheep breed with the aim of documenting the effect of MTNR1A gene polymorphisms on reproductive resumption and to evaluate whether such this effect was modified by differences in body condition score (BCS) and age. Six hundred three- to six-year-old multiparous ewes with BCSs between 2.5 and 3.5 were selected. Genomic DNA was extracted and subjected to PCR to amplify the ovine exon II of the MTNR1A gene. The amplicons were subjected to digestion with the restriction enzymes RsaI and MnlI to detect the T606C and A612G polymorphisms, respectively. Ewes carrying the G/G, G/A, C/C, and C/T genotypes exhibited higher fertility rates (P<0.05) and fewer numbers of days between the introduction of rams and parturition (P<0.05) than did the A/A and T/T genotypes. The data revealed that the MTNR1A gene polymorphisms influenced spring reproductive resumption in the Sarda sheep breed. Moreover, the data also indicated that, over the limited ranges evaluated in this study, BCS and age had no significant influence on reproductive activity.

Sequence analysis and identification of new variations in the coding sequence of melatonin receptor gene (MTNR1A) of Indian Chokla sheep breed

Melatonin receptor 1A gene is the prime receptor mediating the effect of melatonin at the neuroendocrine level for control of seasonal reproduction in sheep. The aims of this study were to examine the polymorphism pattern of coding sequence of MTNR1A gene in Chokla sheep, a breed of Indian arid tract and to identify new variations in relation to its aseasonal status. Genomic DNAs of 101 Chokla sheep were collected and an 824bp coding sequence of Exon II was amplified. RFLP was performed with enzyme RsaI and MnlI to assess the presence of polymorphism at position C606T and G612A, respectively. Genotyping revealed significantly higher frequency of M and R alleles than m and r alleles. RR and MM were found to be dominantly present in the group of studied population. Cloning and sequencing of Exon II followed by mutation/polymorphism analysis revealed ten mutations of which three were non-synonymous mutations (G706A, C893A, G931C). G706A leads to substitution of valine by isoleucine Val125I (U14109) in the fifth transmembrane domain. C893A leads to substitution of alanine by aspartic acid in the third extracellular loop. G931C mutation brings about substitution of amino acid alanine by proline in the seventh transmembrane helix, can affect the conformational stability of the molecule. Polyphen-2 analysis revealed that the polymorphism at position 931 is potentially damaging while the mutations at positions 706 and 893 were benign. It is concluded that G931C mutation of MTNR 1A gene, may explain, in part, the importance of melatonin structure integrity in influencing seasonality in sheep.

Association between melatonin receptor 1A (MTNR1A) gene single-nucleotide polymorphisms and the velvet antler yield of Sika deer

Melatonin, a secretion from pineal gland is ambiguously considered as the key hormone involved in regulation of the antler cycle in Sika deer. To find out more about the roles of melatonin and its receptor gene, we carried out current study to investigate the association between polymorphisms in melatonin receptor 1A (MTNR1A) gene and the antler yield from Sika deer. A total of 251 Sika deer were analyzed in this study, of which consisted of Wusan Sika deer (n = 163) and Dongfeng Sika deer (n = 88). MTNRA gene was amplified by PCR and genotyped by Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Three polymorphism loci (C518T, C629G and C635T) were detected in exon2 of MTNR1A gene. The restriction site Ecol881 was used for C518T while a C629G polymorphism locus was digested with Mval restriction endonucleases. In Wusan Sika deer the allele frequencies of C and T were 0.637 and 0.363 for C518T, Also C and G alleles in C629G locus were 0.206 and 0.794. Genotypic frequencies of allele CC, CT and TT were 33.7, 59.9 and 6.4 % respectively, It showed 1.8, 37.4 and 60.7 % for frequencies of genotypes CC, CG and GG. In Dongfeng Sika deer the allele frequencies of C and T were 0.518 and 0.482 for C518T, C and G alleles were 0.375 and 0.625 for C629G. Genotypic frequencies were 10.6, 82.4 and 7.1 % for genotypes CC, CT and TT respectively, and they were 1.1, 72.7 and 26.2 % for genotypes CC, CG and GG. Among three SNPs, only C629G showed significant association (P < 0.05) with average antler yield in Wusan Sika deer, while no SNP was significant in Dongfeng Sika deer. These preliminary results implied that the identified SNPs of MTNR1A gene might influence the antler yield in Wusan Sika deer.

Genetic polymorphism of melatonin receptor 1A (MTNR1A) gene in Indian sheep breeds

Polymorphism in the melatonin receptor 1A (MTNR1A) is associated with seasonal reproduction of sheep. Genetic polymorphism in MTNR1A gene was investigated in 4 Indian sheep breeds reared in semi-arid and arid region of the Rajasthan. In this study, blood samples were collected from 171 animals. DNA was extracted from white blood cells. The PCR product (824bp) of exon II fragment of sheep MTNR1A gene was amplified. PCR products were digested separately with 2 restriction endonucleases, viz. MnII and RsaI. Polymorphism was detected at both loci of MTNR1A gene. At MnII locus, allele frequency for Magra, Garole, Malpura and Avikalin breed was found as 0.74, 0.74, 0.78, and 0.84 for M allele and 0.26, 0.26, 0.22, 0.16 for N allele, respectively. At RsaI locus, allele frequency was found as 0.90, 0.83, 0.69, and 0.59, for R allele and 0.10, 0.17, 0.31, 0.41 for r allele, respectively. It was concluded that the frequencies of ‘M’ and ‘R’ alleles of MTNR1A were higher in Indian sheep breeds.