Genetic polymorphism of Pit-1 and CSN3 genes in Holstein calves and its associations with calf birth weight

Abstract. The aim of this study was to examine the polymorphic structures of Pit-1 and CSN3 genes of Holstein calves bred in Gümüşhane province of Türkiye, to determine the distribution of genotype and allele gene frequencies, as well as examine the effects of determined polymorphisms on birth weight of calves. HinfI polymorphisms of Pit-1 and CSN3 genes were identified in DNA isolated from blood samples of 100 Holstein calves used in the study, using the PCR-RFLP method. According to the Hardy–Weinberg genetic equilibrium test, it was observed that the distribution of genotype frequencies of HinfI polymorphisms of Pit-1 genes in the studied population was in equilibrium, but not in equilibrium in terms of CSN3 gene location. The AA, AB, and BB genotype frequencies of the Pit-1 gene in the population were 13.4 %, 40.2 %, and 46.3 %, respectively; the frequency of the A allele was 0.34, while for B allele it was 0.66. The AA, AB, and BB genotype frequencies of the CSN3 gene were found to be 24.5 %, 36.7 %, and 38.8 %, respectively; the frequency of the A allele was 0.43 and the frequency of the B allele was 0.57. According to the Hardy–Weinberg genetic equilibrium test, the distribution of genotype frequencies was in equilibrium in the Pit-1/HinfI polymorphism, but not in the CSN3/HinfI polymorphism. A statistically significant relationship was not found between the genotypes of both polymorphic regions and calf birth weight.

Characterization of third exonic region of POU1F1 gene in the Osmanabadi breed of goat

The POU1F1 gene has been identified as one of the major gene for productivity, and its polymorphism is known to be associated with important production traits of various livestock. The present study was designed to investigate POU1F1 (exon-3) gene polymorphism and its association with body weight in Osmanabadi goat (n=217). The PCRSSCP and DNA sequencing revealed single ‘C’ > ‘T’ transition at nucleotide position 42 in the third exonic region (225 bp) POU1F1 gene of Osmanabadi goat. Genotyping revealed ‘TT’ and ‘CC’ genotypes with predominance of ‘C’ allele in the Osmanabadi goat population. Though no association between the said SNP and body weight was observed, these findings can be extended to find the genetic variability of POU1F1 gene associated with growth traits of various Indian goat breeds.

Association of milk production traits with genetic variants in exon 5 and intron 3 of bovine growth hormone (bGH) gene in Sahiwal cattle

The main objective of this study was to determine the association of production traits with genetic variants in exon 5 and intron 3 of bovine growth hormone (bGH) gene in Sahiwal cattle. The analyses were based on the detection of single nucleotide polymorphisms (SNPs) in GH-AluI (exon 5) and GH-MspI (intron 3) using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. The frequency of AluI (L/V) and MspI (T/C) alleles were 86.20/13.70 and 89.80/9.50, respectively. The distribution of the frequency of GH genotypes for LL, LV, and VV were 73.4, 25.5, and 1.0 and for TT, TC, and CC genotypes were 80.9, 17.7, and 13.0, respectively. Season of calving had none but period of calving had significant effect on the studied production traits. The phenotypic data was adjusted for non-genetic factors and regression analysis was done. There was detectable significant effect of the GH-AluI and GH-MspI on the analyzed production traits. The cows with LL genotype had significantly higher milk yield traits than the LV genotype. Similarly, the productive performance of the studied cows with TT genotype was also significantly higher than TC and CC genotypes. Results revealed that the Sahiwal cows with LL and TT genotypes of the bGH locus can be considered to be a favourable genotype for production traits, although these findings need to be confirmed by further research before SNPs can be used in a marker assisted selection program by the animal breeder.

Preferred and undesirable genotypes of bGH and bIGF-1 genes for the milk yield and quality of black-and-white breed

Background and Aim:

The market demand for the quality of milk and dairy products, in particular in terms of such indicators as fat content, the amount and composition of milk protein, etc., is growing. Thus, the need for the selection of dairy herds using genetic markers associated with qualitative traits of milk productivity is becoming urgent. This study aimed to determine the preferred and undesirable genotypes of the AluI polymorphism of the growth hormone gene and SnaBI polymorphism of the insulin-like growth factor-1 gene associated with milk productivity and quality indicators of the black-and-white breed. The genotypes of animals were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

Materials and Methods:

Samples of the black-and-white breed from Kazakhstan served as the research subjects. The polymorphism of the growth hormone and insulin-like growth factor-1 genes was determined by PCR-RFLP. The relationship of bGH-AluI and bIGF-1-SnaBI polymorphisms with productivity was assessed (fat, protein, and milk yield for 305 days of lactation, live weight, somatic cells, and milk production coefficient) by analysis of variance using Statistica 6.0 software.

Results:

The black-and-white cows with the bGH-Alu^ILV genotype had significantly higher milk yield in 305 days (3174.5±157.2 kg) than those with the bGH-AluI^LL (2940.0±152.6 kg) and bGH-AluI^VV genotypes (2964.0±36.0; p<0.05). The milk fat content of cows with genotypes bGH-AluI^LV and bGH-AluI^LL (121.8±6.5 and 120.6±10.2, respectively) was significantly higher than those with bGH-AluI^VV genotype (109.8±10.8; p<0.05). The black-and-white cows with the bGH-AluI^LV genotype (96.7±5.3) had significantly more milk protein than those with the bGH-AluI^LL (90.3±5.6) and bGH-AluI^VV (86.9±4.6) genotypes (p<0.05). There were no statistically significant differences in the indicators of milk productivity of cows with different genotypes of bIGF-1-SnaBI polymorphism.

Conclusion:

The results showed that the bGH-AluI^LV genotype was preferred for the black-and-white breed. The study demonstrated that genotype determined the relevant qualities, while the conditions of feeding, maintenance, and industrial technology provided the manifestation of this genotype. Thus, cows of the same (Wis Burke Ideal) line, having common ancestors in close (IV–V) ranks but living in different farming conditions, had large differences in milk productivity level. The variation was 2046 kg or 67.6% of milk per lactation.

Meta-analysis of SNP in growth hormone gene associated with milk traits in dairy cows

Previous studies reported varied findings regarding growth hormone polymorphisms and their association with milk traits in dairy cattle. The objective of the present study was to combine the information of Alu1-derived gene polymorphisms of growth hormone in 6571 dairy cows using 51 published studies for obtaining pooled estimate of gene frequency of L allele in dairy cows and for deriving common effect size of association of gene variants with various milk traits (lactation milk yield, fat yield, fat%, protein yield, and protein%) using meta-analysis. The pooled estimate of gene frequency was obtained using proportion as effect size with 95% confidence interval under random effects model. For association analysis, standardized mean difference was employed as effect size under four genetic models comprising additive (LL vs. VV), dominant (LL + LV vs. VV), completely over dominant (LL + VV vs. LV), and recessive (LL vs. LV + VV). The heterogeneity between studies was estimated using Q test and I² statistic. The results showed that pooled estimate of gene frequency of L allele was 0.81 (95% CI: 0.77, 0.85; I² = 96.86%). Subgroup analysis revealed that it was significantly higher in Bos indicus cows (0.97, 95% CI 0.89, 1.00; I² = 95.15%) than Bos taurus/cross cows (0.78, 95% CI 0.73, 0.82; I² = 96.84%). An association analysis showed that the effects of GH variants on milk-related traits were not significant (P > 0.1) under all genetic models. Substantial range of heterogeneity indicated modest effects of SNP genotypes with milk traits. It was concluded that although allele L is predominant than V allele of GH in dairy cows over large geographical populations, they may not be particularly useful for selection programs for improving milk traits in dairy cows.

Effect of GH p.L127V Polymorphism and Feeding Systems on Milk Production Traits and Fatty Acid Composition in Modicana Cows

Growth hormone participates in the regulation of lactation and lipid metabolism. A trial study was conducted to evaluate the effects of genetic polymorphism at GH p.L127V and its interaction with feeding system (extensive, EX; semi-intensive, SI) on milk traits and fatty acids composition in Modicana cows. In the semi-intensive farm (SI) diet consisted of hay, concentrate and 2 h of grazing. In the extensive farm (EX) feeding consisted in 8 h of grazing and hay. The frequencies of LL, LV and VV genotypes were, respectively: 0.64, 0.34, 0.02. GH polymorphism and its interaction with feeding system did not influence milk yield and composition. Cows carrying LL genotype produced milk with lower 6:0 and 8:0 and higher 16:1 c9 and 18:1 c9, total UFA and total MUFA. Feeding significantly affected fatty acids: in EX cows lower SFA and higher PUFA and UFA were found, compared to SI cows. The lower, more favorable atherogenic index of milk from EX system was coherent with the improved healthy characteristics of milk from animals fed almost exclusively on pasture. A significant interaction genotype x feeding system was evident for 18:1, higher in the LL cows only in the EX system, but not in the SI system.

Assessment of growth hormone gene polymorphism effects on reproductive traits in Holstein dairy cattle in Tunisia

Research to assess the effect of single genes on reproductive traits in bovine species is imperative to elucidate genes' functions and acquire a better perspective of quantitative traits. The present study was undertaken to characterize genetic diversity in the bovine growth hormone (GH) gene in a population of 410 Holstein dairy cows in Tunisia. The analyses were based on single nucleotide polymorphisms, and GH-AluI and GH-MspI detections and genotyping were carried out using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Data were analyzed using a mixed linear model with the MIXED procedure to reveal the possible effect of GH genotypes on reproductive traits. The frequency data of AluI(L//V) and MspI( + // - ) alleles were 87.04//12.96 and 70.06//29.94, respectively. The distribution of the frequency of GH genotypes for LL/LV/VV and ( - / - )//( + / - )//( + / + ) were 77.75//18.59//3.66 and 15.37//29.13//55.50, respectively. The results of the statistical analyses proved that GH-AluI showed a substantial favorable effect on exanimate traits except for the age at first calving; however, only a suggestive effect of GH-MspI on the calving interval (CI) and the days open (DI) was found. The homozygous LL genotype seemed to be advantageous with respect to the CI and the DI compared with LV and VV genotypes. Heterozygous MspI( + / - ) cows tended to have a longer CI and DI than MspI( + / + ) and MspI( - / - ) cows, but the difference was not statistically significant. A significant effect of different GH-AluI-MspI combined genotypes was found on the number of inseminations per conception, the CI and the DI, and the LL/- combined genotype seemed to be associated with better reproductive performance. Based on these results, the LL genotype of the GH locus can be considered to be a favorable genotype for reproductive traits in Holstein dairy cattle, although these findings need to be confirmed by further research before polymorphisms can be used in a marker-assisted selection program.

Identification of Candidate Genes for Reactivity in Guzerat (Bos indicus) Cattle: A Genome-Wide Association Study

Temperament is fundamental to animal production due to its direct influence on the animal-herdsman relationship. When compared to calm animals, the aggressive, anxious or fearful ones exhibit less weight gain, lower reproductive efficiency, decreased milk production and higher herd maintenance costs, all of which contribute to reduced profits. However, temperament is a trait that is complex and difficult to assess. Recently, a new quantitative system, REATEST^®, for assessing reactivity, a phenotype of temperament, was developed. Herein, we describe the results of a Genome-wide association study for reactivity, assessed using REATEST^® with a sample of 754 females from five dual-purpose (milk and meat production) Guzerat (Bos indicus) herds. Genotyping was performed using a 50k SNP chip and a two-step mixed model approach (Grammar-Gamma) with a one-by-one marker regression was used to identify QTLs. QTLs for reactivity were identified on chromosomes BTA1, BTA5, BTA14, and BTA25. Five intronic and two intergenic markers were significantly associated with reactivity. POU1F1, DRD3, VWA3A, ZBTB20, EPHA6, SNRPF and NTN4 were identified as candidate genes. Previous QTL reports for temperament traits, covering areas surrounding the SNPs/genes identified here, further corroborate these associations. The seven genes identified in the present study explain 20.5% of reactivity variance and give a better understanding of temperament biology.

Identification of novel isoforms of dairy goat EEF1D and their mRNA expression characterization

Eukaryotic translation elongation factor 1 delta (EEF1D) gene encodes guanine nucleotide exchange protein eEF1Bδ, which participates in the eukaryotic protein synthesis, and plays important roles in regulating cell cycling and milk production. This study firstly focused on detecting the isoforms of dairy goat EEF1D gene and their mRNA expression characterization. Herein, two novel isoforms, EEF1Da and EEF1Dc, were identified in dairy goat. The entire coding sequences of EEF1Da and EEF1Dc isoforms were 843bp and 267bp in length, respectively. Goat EEF1Da had complete conserved domains of elongation factor 1 (EF1) family, and the evolution of goat EEF1Da isoform was agreed with the evolution of species. Expression pattern analysis of different isoforms revealed relatively ubiquitous expression of EEF1D and EEF1Da. While EEF1Dc only expressed in heart, lung, kidney, adipose and muscle. Combining with the analysis results of cloning, qRT-PCR and bioinformatics, EEF1Da is the major alternative splicing form of EEF1D gene. Interestingly, qRT-PCR result showed that the highest expression of EEF1D was in adipose, which is the major component of mammary. This result was consistent with the early research that EEF1D expressed highly in the mammary, which indicated that EEF1D played a potential key role in regulating adipose development and milk production. All these findings would provide a foundation for the further research of EEF1D gene and development of dairy goat industry.