Genotyping of Diacylglycerol Acyltransferase 2 Gene in Holstein Cattle Population

This study was conducted to describe the single nucleotide polymorphism (SNPs) within exon 8 and its intron 9 flanking region within bovine Diacylglycerol Acyltransferase 2 (DGAT2) gene and the possible association of these SNPs with the milk productive traits. Blood samples were collected from randomly selected Holstein cattle. Genomic DNA was extracted, and a pair of specific PCR primers was designed to amplify a segment that consists of partial exon 8/partial intron 9 of DGAT2 gene. SSCP experiments were optimized and performed for each amplified PCR fragment. Each set of SSCP resolved bands was sequenced and analyzed. Four SSCP patterns representing four genotypes (BD, BB, CD, and AD) were detected with four alleles. Several novel genetic polymorphisms were discovered. Three SNPs (157 C/A, 158 T/G, and 159 G/A) were found in genotype BD,  while one SNP (94 G/T,  153 C/A, 154 T/A) were found in the genotypes BB, CD, and AD, respectively. The only non-synonymous SNP was found in genotype CD (344 D/Y), and the effect of this missense mutation on the protein three-dimensional structure was visualized. The sequence homology between the bovine DGAT2 gene and other species was also analyzed. The significance of the correlation of each genotype with the productive traits of milk was observed. The Holstein cattle with BD genotype produced significantly more milk for all studied 90 days of lactation, with a significant effect on fat for only the last 30 days of lactation, whereas there was no effect on protein and lactose percentage for the entire lactation period. The results suggest a novel association between bovine DGAT2 genetic variability and the milk yield in Holstein cattle. This opens interesting prospects for future DGAT2 based selection programs and preservation strategies

Genotyping of Diacylglycerol Acyltransferase 2 Gene in Holstein Cattle Population

This study was conducted to describe the single nucleotide polymorphism (SNPs) within exon 8 and its intron 9 flanking region within bovine Diacylglycerol Acyltransferase 2 (DGAT2) gene and the possible association of these SNPs with the milk productive traits. Blood samples were collected from randomly selected Holstein cattle. Genomic DNA was extracted, and a pair of specific PCR primers was designed to amplify a segment that consists of partial exon 8/partial intron 9 of DGAT2 gene. SSCP experiments were optimized and performed for each amplified PCR fragment. Each set of SSCP resolved bands was sequenced and analyzed. Four SSCP patterns representing four genotypes (BD, BB, CD, and AD) were detected with four alleles. Several novel genetic polymorphisms were discovered. Three SNPs (157 C/A, 158 T/G, and 159 G/A) were found in genotype BD,  while one SNP (94 G/T,  153 C/A, 154 T/A) were found in the genotypes BB, CD, and AD, respectively. The only non-synonymous SNP was found in genotype CD (344 D/Y), and the effect of this missense mutation on the protein three-dimensional structure was visualized. The sequence homology between the bovine DGAT2 gene and other species was also analyzed. The significance of the correlation of each genotype with the productive traits of milk was observed. The Holstein cattle with BD genotype produced significantly more milk for all studied 90 days of lactation, with a significant effect on fat for only the last 30 days of lactation, whereas there was no effect on protein and lactose percentage for the entire lactation period. The results suggest a novel association between bovine DGAT2 genetic variability and the milk yield in Holstein cattle. This opens interesting prospects for future DGAT2 based selection programs and preservation strategies

Fatty Acid Synthase Polymorphism of Awassi Sheep and its Impact on Fatty Acid Composition

Livestock intramuscular fat content is determined by fatty acid synthase (FASN).  The fatty acid profile of the fat is of relevance to human health.  Thus, this study explores the relationship between the polymorphism of the FASN gene in Awassi sheep and its impact on fatty acid composition.  The study used 100 Awassi rams, ranging in age from 1 to 2.5 years.  Molecular DNA was isolated from each blood sample; genotyping, sequencing reactions, and in silico tools were subsequently used to confirm the variants in amplified fragments.  The results revealed two genotypes (GG and GA) of the ovine FASN gene (exon 2).  The novel missense c.186 GA was identified in the genotype GA.  The GA genotype had significantly (P0.05) increased intramuscular fat, higher unsaturated fatty acid content, and lower saturated fatty acid content than the GG genotype.  Cumulative in silico analysis indicated a detrimental effect of the SNP c.186 GA on FASN activity.  The intramuscular GA genotype of Awassi sheep had a low saturated content relative to unsaturated fats.  The result confirmed that the c.186 GA SNP in ovine FASN gene variation is potentially helpful in assessing carcass traits, and this might lead to a more efficient selection of animals with healthier fatty acid profiles, resulting in higher-quality meat

A Missense p.Q>R234 Mutation in the Osteopontin Gene Is Associated With the Prolificacy of Iraqi Awassi Ewes

One of the most valuable traits in production and breeding is a sheep’s prolificacy which is influenced by several genes, one of which is the osteopontin ( OPN ) gene. Thus, this study aimed to determine the effect of genetic variation within the OPN gene on Awassi ewe prolificacy. Genomic DNA was extracted from 123 single-progeny ewes and 109 twin ewes. Polymerase chain reaction (PCR) was used to amplify 4 sequence fragments (289, 275, 338, and 372 bp), representing exons 4, 5, 6, and 7 of the OPN gene. A 372 bp amplicon was identified with 3 different genotypes: TT, TC, and CC. Sequence analysis revealed a novel mutation in TC genotypes p.Q>R234. Statistical analysis revealed that the single nucleotide polymorphism (SNP) p.Q>R234 was associated with prolificacy. Ewes carrying the p.Q>R234 SNP had significantly ( P  ⩽ .01) lower litter sizes, twinning rates, and lambing rates, and more days to lambing than those with the TC and TT genotypes. The p.Q>R234 SNP was confirmed to be responsible for lower litter size through logistic regression analysis. From these results, we can conclude that the missense variant p.Q>R234 adversely affects the traits of interest and shows that the p.Q>R234 SNP negatively influences the prolificacy of Awassi sheep. Based on this study, it is evident that ewes in this population carrying the p.Q>R234 SNP have a lower litter size and are less prolific

A novel deleterious oxytocin variant is associated with the lower twinning ratio in Awassi ewes

This study aimed to assess the possible association of oxytocin (OXT) gene with reproductive traits in two groups of Awassi ewes that differ in their reproductive potentials. Sheep were genotyped using PCR—single-stranded conformation polymorphism approach. Three genotypes were detected in exon 2, CC, CA, and AA, and a novel SNP was identified with a missense effect on oxytocin (c.188C > A → p.Arg55Leu). A significant (p in silico tools that were utilized to assess the effect of this variant on the structure, function, and stability of oxytocin. Molecular docking showed that p.Arg55Leu caused a dramatic alteration in the binding of oxytocin with its receptor and reduced the number of interacted amino acids between them. Our study suggests that ewes with AA and CA genotypes showed a lower reproductive performance due to the presence of p.Arg55Leu, which caused damaging impacts on oxytocin and is binding with the OXT receptor. The utilization of the p.Arg55Leu could be useful for improving Awassi reproductive potential.</p