Combined effects of four SNPs within goat PRLR gene on milk production traits

Xinong Saanen (SN, n = 323) and Guanzhong (GZ, n = 197) goat breeds were used to detect single nucleotide polymorphisms (SNPs) in the coding regions with their intron–exon boundaries of prolactin receptor (PRLR) gene by DNA sequencing, primer-introduced restriction analysis-polymerase chain reaction (PIRA-PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP). Four novel SNPs (g.40452T > C, g.40471G > A, g.61677G > A and g.61865G > A) were identified. The g.61677G > A and g.61865G > A SNPs caused amino acid variations p.Ser485Asn and p.Val548Met, respectively. Both g.40452T>C and g.40471G>A loci were closely linked in SN and GZ goat breeds (r² > 0.33). In addition, there was also a close linkage between g.61677G>A and g.61865G>A loci in both goat breeds. Statistical results indicated that the g.40452T > C, g.61677G > A and g.61865G > A SNPs were significantly associated with milk production traits in SN and GZ breeds. Further analysis revealed that combinative genotype C1 (TTAAGGGG) was better than the others for milk yield in SN and GZ goat breeds. These results are consistent with the regulatory function of PRLR in mammary gland development, milk secretion, and expression of milk protein genes, and extend the spectrum of genetic variation of the caprine PRLR gene, which might contribute to goat genetic resources and breeding.     

Distribution of GSTM1, GSTT1, GSTP1 and TP53 disease-associated gene variants in native and urban Venezuelan populations

The contemporary Venezuelan population is the product of major admixture process across various historical events, which has provided it a particular genetic background. The aim of this study concerns the analysis of glutathione S-transferase (GST) GSTM1, GSTP1 and GSTT1 genetic variants and five polymorphisms at the TP53 gene, which are related to cancer susceptibility, in an urban/admixed population and five Amerindian tribes (Bari, Panare, Pemon, Warao and Wayuu) from Venezuela. Genotyping was carried out in 120 individuals from an urban sample and 188 Amerindians. The analysis performed on TP53 haplotype and GST allele distribution showed a close correlation for Pemon and Warao populations, while Bari group appears isolated from the other populations. GSTT1 null variant frequency in our admixed (11%) and native samples (0.0–11.4%) was lower when compared with Caucasians, Africans and Asians. Frequency of the GSTP1*Val cancer-associated allele found in Bari (88.6%) and Panare (63.0%) is of the highest so far reported. Fourteen TP53 haplotypes were observed in the admixed populations, whereas only 3 to 5 in Amerindians. To our knowledge this is the first report of GST polymorphisms and TP53 haplotype distribution in Venezuelans. The distribution of most of analyzed polymorphisms in the urban sample is consistent with the admixed origin of the present-day population of Venezuela. While, the inter-ethnic variations in genetic polymorphisms found in Native American tribes seem to be the result of the influence of demographic factors. These results provide additional data for undertaking ethnographic and disease association studies in Venezuela.     

Characterisation of the genetic effects of the ADFP gene and its association with production traits in dairy goats

Adipose differentiation-related protein (ADFP) is important for regulation of lipid metabolism and insulin secretion in beta-cells. In this study, we investigated polymorphisms within the caprine ADFP gene and determined its relationship with production traits. As there was no sequence information available for the caprine ADFP gene, we generated DNA sequence data and examined the genomic organisation. The caprine ADFP gene is organised into 7 exons and 6 introns that span approximately 8.7 kbp and is transcribed into mRNA containing 1353 bp of sequence coding for a protein of 450 amino acids. The protein sequences showed substantial similarity (71–99%) to orthologues from cattle, human and mouse. We identified polymorphisms in the sequences using DNA sequencing, PCR-RFLP and forced PCR-RFLP methods. Seven single nucleotide polymorphisms (SNPs) were identified using samples from 4 different goat populations consisting of 1408 healthy and unrelated individuals. Six haplotypes involving the 7 SNPs from the caprine ADFP gene were identified and their effects on production traits were analysed. Haplotype 6 had the highest haplotype frequency and was highly significantly associated with chest circumference and milk yield in the analysed populations. The results of this study suggest that the ADFP gene is a strong candidate gene affecting production traits and may be used for marker-assisted selection and management in Chinese dairy goat breeding programmes.     

Combined effects of the UGT1A1 and OATP2 gene polymorphisms as major risk factor for unconjugated hyperbilirubinemia in Indian neonates

Genetic association studies have linked a number of single nucleotide polymorphisms (SNPs) with unconjugated hyperbilirubinemia. The present study was undertaken to validate the association of SNPs with development of hyperbilirubinemia in Indian neonates. Genotyping of five SNPs in two candidate genes was performed in 126 infants with hyperbilirubinemia and 181 controls by PCR-RFLP, Gene Scan analysis and direct DNA sequencing. Genetic polymorphisms of the UGT1A1 promoter, specifically the − 3279 T ? G phenobarbital responsive enhancer module (rs4124874) and (TA)7 dinucleotide repeat (rs8175347) as well as the coding region variants (rs2306283 and rs4149056) of the OATP2 gene were significantly higher among the cases than the controls. The presence of the mutant haplotypes either in homozygous, heterozygous or compound heterozygous state had a significant effect on neonatal hyperbilirubinemia as well as on the requirement of phototherapy than those with the wild haplotype. Further, a significantly higher number of hyperbilirubinemic cases had ≥ 3 variants than the controls (73.80% vs 40.36%, p < 0.0001) and the mean total serum bilirubin levels and requirement of phototherapy also increased according to the number of variants co-expressed. This study demonstrates that UGT1A1 and OATP2 polymorphisms were associated with altered bilirubin metabolism and could be genetic risk factors for neonatal hyperbilirubinemia.     

Determination of common genetic variants in cytidine deaminase (CDA) gene in Indian ethnic population

Cytidine deaminase (CDA) is the major enzyme involved in metabolism of gemcitabine, a pyrimidine analog widely used for chemotherapy of solid tumors. While only low amounts of administered gemcitabine undergo intracellular phosphorylation into active forms and involve in antineoplastic activities, majority of it is rapidly inactivated by CDA and excreted to avoid drug toxicity. Knowledge of the genetic polymorphisms mildly effecting cellular activity of the enzyme CDA is therefore crucial to understanding drug-induced toxicities associated with gemcitabine. Functional significance and allele frequencies for common SNPs including 79A>C (*2) and 208G>A (*3) have been reported in various ethnic populations including Caucasian, African, Korean and Japanese. However, such studies have not been reported in any Indian sub-population. In the present study, conventional polymerase chain reaction (PCR) based amplification using gene specific primers and Sanger sequencing were performed to identify CDA variants in 50 healthy individuals from Indian sub-population. Established common variant 79A>C known to reduce CDA activity was observed at a frequency of 0.14 in the study cohort. In addition to other known variants, one novel variant, c.325−209T>C was detected at a frequency of 0.06. Genetic variants in CDA gene and their frequencies established in our study hold value in pharmacogenetics.     

Associations between two novel rSNPs in 5'-flanking region of the bovine casein gene cluster and milk performance traits

Ten evolutionary conservative sequences with high identity level to homological sequences in other mammal species were revealed in 5'-flanking region of casein's genes cluster. Five novel SNPs located inside of the evolutionary conservative regions were identified. The binding sites were revealed to be present in one allelic variant of four detected SNPs. So these SNPs were considered as rSNPs. Significant differences of allelic frequencies were revealed between beef cow's group and dairy cow's group in two rSNPs (NCE4, NCE7, p<0.001). Different alleles of those two rSNPs were shown to be associated with some milk performance traits in Black-and-White Holstein dairy cows. Significant difference of protein percentage has been found between cows with G/G and A/A genotypes (P<0.05) and A/G and A/A genotypes (P<0.05) for NCE4 polymorphism. The groups of animals with genotypes G/G and A/G for NCE7 polymorphism were significantly different in milk yield at the first lactation (kg) (P<0.01), milk fat yield (kg) (P<0.05) and milk protein yield (kg) (P<0.01). For the last trait the difference was significant also between cows with genotypes G/G and A/A for rSNP NCE7 (P<0.05).     

SNP exploring in the middle and terminal regions of the IGF-1 gene and association with production and reproduction traits in Holstein cattle

Five primer sets were designed in order to identify single nucleotide polymorphisms (SNPs) in middle and terminal exons (2 to 6) and in some flanking intronic regions of the bovine insulin-like growth factor 1 (IGF-1) gene. Sequencing results of PCR products for 10% of animals showed no variant in exons but a SNP at intron 4 was occurred. Both polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) and high resolution melting (HRM) methods were developed to genotype samples. The PCR–RFLP results showed the presence of three fragments on agarose gel for the C allele due to two cleavage sites while two fragments for the T allele were observed. Melting curves of 123 bp fragments in HRM analysis showed a difference between temperature melting (T_m) of two homozygous genotypes as the CC genotypes had higher T_m than the TT genotypes. Melting curve of the CT genotype was different and crossed two parallel patterns of homozygous genotypes. The frequencies of the CC, CT and TT genotypes were 0.6, 0.37 and 0.03, respectively. Also, the estimated allele frequencies were 0.785 and 0.215 for the C and T alleles, respectively. Results showed higher accuracy of the HRM analysis compared to the PCR–RFLP method. Least square means (LSMs) comparison of the different genotypes in the SNP showed significant association with milk fat yield trait in the first lactation and open days after the second calving. The polymorphism did not have a significant effect on other milk production or reproduction traits. It seems that other variants or QTLs known in this region underlie genetic variation in the production and reproduction of dairy cattle.     

Novel polymorphisms of the APOA2 gene and its promoter region affect body traits in cattle

Apolipoprotein A-II (APOA2) is one of the major constituents of high-density lipoprotein and plays a critical role in lipid metabolism and obesity. However, similar research for the bovine APOA2 gene is lacking. In this study, polymorphisms of the bovine APOA2 gene and its promoter region were detected in 1021 cows from four breeds by sequencing and PCR-RFLP methods. Totally, we detected six novel mutations which included one mutation in the promoter region, two mutations in the exons and three mutations in the introns. There were four polymorphisms within APOA2 gene were analyzed. The allele A, T, T and G frequencies of the four loci were predominant in the four breeds when in separate or combinations analysis which suggested cows with those alleles to be more adapted to the steppe environment. The association analysis indicated three SVs in Nangyang cows, two SVs in Qinchun cows and the 9 haplotypes in Nangyang cows were significantly associated with body traits (P < 0.05 or P < 0.01). The results of this study suggested the bovine APOA2 gene may be a strong candidate gene for body traits in the cattle breeding program.     

The association of MDR1 C3435T and G2677T/A polymorphisms with plasma platelet-activating factor levels and coronary artery disease risk in Turkish population

Increased levels of peripheral proinflammatory mediators can contribute to the development of coronary artery disease (CAD). Platelet activating factor (PAF) is an important proinflammatory mediator and plasma levels of PAF correlate with transmembrane transporter multidrug resistant 1 P-glycoprotein (MDR1 Pgp) expression and activity. MDR1 polymorphisms can affect the expression and activity of Pgp and plasma PAF levels. Therefore, we investigated the possible relationship between MDR1 C3435T and G2677T/A polymorphisms and plasma PAF levels and the risk of CAD. The study population consisted of 198 patients angiographically documented CAD, including 113 cases with at least 1 coronary artery with ≥ 50% luminal diameter stenosis and 85 control subjects with strictly normal coronary angiograms. Genotypes of the MDR1 C3435T and G2677T/A polymorphisms were determined by polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP). Plasma PAF levels were detected by enzyme-linked immunosorbent assay (ELISA). There were no significant differences among plasma PAF levels in regard to MDR1 C3435T and G2677T polymorphisms in CAD patients and controls. No statistically significant difference was found for the genotypic and allelic distributions of the polymorphisms in the MDR1 gene between the patients and the control subjects. Furthermore, analysis of MDR1 haplotypes did not show any associations with increased plasma PAF levels and risk of CAD. Our results suggest that plasma PAF levels are not associated with MDR1 gene polymorphisms. There is no association between MDR1 C3435T and G2677T/A polymorphisms and the risk of CAD in Turkish patients.     

Identification of bovine NPC1 gene cSNPs and their effects on body size traits of Qinchuan cattle

NPC1 gene is an important gene closely related to the Niemann–Pick type C (NPC). Mutations in the NPC1 gene tend to cause Niemann–Pick type C, a lysosomal storage disorder. Previous studies have shown that NPC1 protein plays an important role in subcellular lipid transport, homeostasis, platelet function and formation, which are basic metabolic activities in the process of development. In this study, to explore the association between the NPC1 gene variation and body size traits in Qinchuan cattle, we detected four novel coding single nucleotide polymorphisms (cSNPs) in the bovine NPC1 gene, including one missense mutation (SNP1) and three synonymous mutations (SNP2, SNP3 and SNP4). Population genetic analyses of 518 individuals and association correlations between cSNPs and bovine body size traits were conducted in this research. A missense mutation at SNP1 locus was found to be significantly related to the heart girth, hip width and body weight (P < 0.01 or P < 0.05, 3.5-year-old). Two synonymous mutations at SNP2 and SNP3 loci also showed significant effects on hip width (P < 0.05, 3.5-year-old). One synonymous mutation at SNP4 locus showed significant effect on body weight (P < 0.05, 2.0-year-old). Combined haplotypes H₂H₆ and H₆H₆ showed significant effects on body size traits such as heart girth, hip width, and body weight (3.5-year-old, P < 0.01 or P < 0.05). This study provides evidence that the NPC1 gene might be involved in the regulation of bovine growth and body development, and may be considered as a candidate gene for marker assisted selection (MAS) in beef cattle breeding industry.     

Effects of a novel SNP of IGF2R gene on growth traits and expression rate of IGF2R and IGF2 genes in gluteus medius muscle of Egyptian buffalo

Insulin-like growth factor 2 receptor (IGF2R) is responsible for degradation of the muscle development initiator, IGF2, and thus it can be used as a marker for selection strategies in the farm animals. The aim of this study was to search for polymorphisms in three coding loci of IGF2R, and to analyze their effect on the growth traits and on the expression levels of IGF2R and IGF2 genes in the gluteus medius muscle of Egyptian buffaloes. A novel A266C SNP was detected in the coding sequences of the third IGF2R locus (at nucleotide number 51 of exon 23) among Egyptian water buffaloes. This SNP was non-synonymous mutation and led to replacement of Y (tyrosine) amino acid (aa) by D (aspartic acid) aa. Three different single-strand conformation polymorphism patterns were observed in the third IGF2R locus: AA, AC, and CC with frequencies of 0.555, 0.195, and 0.250, respectively. Statistical analysis showed that the homozygous AA genotype significantly associated with the average daily gain than AC and CC genotypes from birth to 9 mo of age. Expression analysis showed that the A266C SNP was correlated with IGF2, but not with IGF2R, mRNA levels in the gluteus medius muscle of Egyptian buffaloes. The highest IGF2 mRNA level was estimated in the muscle of animals with the AA homozygous genotype as compared to the AC heterozygotes and CC homozygotes. We conclude that A266C SNP at nucleotide number 51 of exon 23 of the IGF2R gene is associated with the ADG during the early stages of life (from birth to 9 mo of age) and this effect is accompanied by, and may be caused by, increased expression levels of the IGF2 gene.     

Genetic structure,polymorphism identification of LGP2 gene and their relationship with the resistance/susceptibility to GCRV in grass carp, Ctenopharyngodon idella

Laboratory of genetics and physiology 2 (LGP2) is an actual detector and regulator during RNA viral infection in innate immunity. In this study, 5′-flanking region and all introns of LGP2 in grass carp (Ctenopharyngodon idella) were excavated. The genomic CiLGP2 (C. idella LGP2) was 8062 bp in length, with a 364 bp 5′-flanking region, twelve exons and eleven introns. Besides, the promoter activity of the upstream region before initiator codon was identified. By sequencing, six single nucleotide polymorphisms (SNPs) and one 20-bp insertion/deletion polymorphism were detected in CiLGP2. With a challenge experiment, the genotype and allele distributions of these seven polymorphisms were examined. Analytic result revealed only the − 1392 C/G, 494 A/T and 4403 C/T loci were significantly associated with the resistance/susceptibility to grass carp reovirus (GCRV) (P < 0.05). To further identify these correlations, another independent challenge test was performed. The analytic result based on the cumulative mortality demonstrated that the stock in − 1392 GG genotype was more susceptible to GCRV than that in CC genotype, while the stocks in 494 TT genotype and 4403 TT genotype were more resistant to GCRV than that in AA and CC genotype stocks, respectively (P < 0.05). Those significant SNPs might be potential gene markers for the future molecular selection of C. idella strains that are resistant to GCRV.