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Fresh semen from fifty bulls was evaluated for ejaculate volume, individual motility, concentration, lives sperm and abnormalities as well as acrosome integrity. Bulls were classified according to semen motility into two groups; good and poor. DNA was extracted from semen of both groups, then the PCR followed by single-strand conformation polymorphism (SSCP) techniques were performed for mutation detection in gonadotropin releasing hormone receptor (GnRHR) gene through multiple sequence alignment. The results showed that the percentages of sperm motility, sperm concentration and live sperm, were significantly higher in good than poor semen quality bulls. However, semen volume, percentage of acrosome integrity and abnormalities did not differ between good and poor. The PCR amplification of 240-bp fragment and the results of SSCP appeared a genetic polymorphism with two patterns. Pattern I was seen in all good bulls, with incidence of 100%. Pattern II appeared only in poor semen quality bulls with a frequency of 31.25%. The sequence analysis of the PCR product for the two patterns showed two single nucleotide polymorphisms (SNPs) as a transversion base substitution mutation at positions 20 (T/A) and 193 (A/T). The GnRHR gene could be used as a genetic marker related to semen quality in buffalo due to the good semen bulls had a unique pattern.

In the present study, the association of Gonadotropin-Releasing Hormone Receptor gene (GnRHR) and litter size were investigated using the PCR-RFLP method as a genetic marker candidate for litter size in 35 individuals from Ettawa crossbreed goats. This research has two steps conducted in the laboratory and in the field. Data on litter size and blood samples were collected from the field. In the laboratory was carried out DNA isolation, amplification, and restriction. Molecular analysis of DNA isolation were precise, the enzyme Msp1 (C*CGG) with a product length of 706 bp was used for amplification and restriction analysis, releaved TT genotype in GnRHR gene fragment. In the exon 3 of chromosome 6, the single nucleotide polymorphism (SNP) c.18085 T>G was found. Ettawa crossbreed goat in calculations using the hardy-weinberg law, insignificant results are obtained because the value is more than > 0.05 (db; 1) = 0.50. The genotypes and allele frequencies found in the Ettawa Crossbreed Goat GnRHR genes are monomorphic and the GnRHR gene did not associate with litter size. The conclusion is that GnRHR exon 3 gene (SNP) c.18085 T>G did not associate with litter size and can not be used as a genetic marker on Ettawa crossbred goats.

In the present study, the polymorphism of gonadotropin-releasing hormone receptor (GnRHR) gene was analysed as a candidate gene for reproductive traits in 90 female goats belonging to Barbari, Sirohi and Black Bengal breed. Two alleles (A and B) and three genotypes (AA, AB and BB), were detected. The frequencies of alleles A and B in three goat breeds ranged 0.52-0.60 and 0.40-0.48, respectively. The gene locus was in Hardy-Weinberg (HW) disequilibrium in Barbari and Sirohi goats where as it is found to be in HW equilibrium in Black Bengal breed at exon 2. The results showed significant (P ≤ 0.01) effect of breed on reproductive traits whereas effect of genotype was not significant. Although the result showed no significant association of genotype with the traits under study, some genotypes showed superiority over others in terms of litter size, age at sexual maturity and first kidding, suggesting that GnRHR gene could serve as a candidate gene. There is however need to further validate the investigation using large sample sizes for the breeds under consideration. [ABSTRACT FROM AUTHOR]

Gonadotropin-releasing hormone receptor ( GnRHR) gene is considered a candidate gene for litter size due to its critical role in regulating the activities of hypothalamo-pituitary-gonadal axis which synthesizes and releases gonadotropins. This study was designed to identify mutations within the caprine GnRHR gene and investigate their association with litter size at various parities. Polymorphisms scanning and genotyping of GnRHR gene in West African Dwarf (WAD) goats (n = 226) revealed three single nucleotide polymorphisms (SNPs), one mutation (g.-29T > G) was detected within 5′UTR region while two others (g.48G > A and g.209T > G) were identified in exon 1. Mutation at g.209T > G locus resulted in amino acid change from Methionine to Arginine at position 70 on the polypeptide residue. Based on heterozygosity and polymorphism information content (PIC), WAD goat population diversity at the SNP loci was moderate. Strong linkage disequilibrium (LD) (r > 0.98) existed among the detected mutations resulting in three observed haplotypes, two (T-G-T and G-A-G) had cumulative frequency of > 97%. The mutation within 5′UTR region of GnRHR gene (g.-29T > G) is novel, being reported in goats for the first time. Association analysis revealed a significant (p < 0.05) association between allele G at g.-29T > G with higher mean litter size for homozygous (GG) mutant does compared with heterozygotes (GT) or homozygotes (TT), while the relationship between SNPs at the two loci detected in exon 1 and litter size was not significant. [ABSTRACT FROM AUTHOR]

Gonadotropin-releasing hormone receptor ( GnRHR ) plays a critical physiological role in animal reproduction and is a potential marker for improving sperm quality. In the present study, eight SNPs (g.539T > C, g.640A > G, g.655T > C, g.707T > C, g.812A > G, g.18951A > T g.16867T > C and g.18953Indel GGCAAAGTAA) were detected in the GnRHR gene from one-hundred-sixty-five water buffalo by direct sequencing and identification of overlapping peaks. All SNPs were associated significantly with the ejaculate volume and two genes (g.655T > C and g.707T > C) were correlated with sperm abnormalities. Furthermore, three haplotypes (H1:TAI, H2:CT-, and H3:TT-) were identified by linkage disequilibrium analysis and were composed of four combined genotypes. Notably, buffalo with the combined genotypes H1H2 and H1H3 had the higher ejaculate volume compared to the other combined genotypes. Among the eight SNPs and four combined genotypes, the deletion of GGCAAAGTAA at position 18953 bp in GnRHR was associated significantly with a higher ejaculate volume. Moreover, the GGCAAAGTAA deletion may lead to the miR8661 binding failure and subsequent changes in GnRHR gene expression. In the present study, we demonstrate that there is a significant association between SNPs in the GnRHR gene and the sperm ejaculate volume of Chinese water buffalo. To the best of our knowledge, this study is the first to address the association between the SNPs in the GnRHR gene and the sperm quality of Chinese buffalo. [ABSTRACT FROM AUTHOR]