Association study between β-defensin gene polymorphisms and mastitis resistance in Valle del Belice dairy sheep breed

An in silico evaluation of non-synonymous single nucleotide polymorphisms of mastitis resistance genes in cattle

Recognition of deleterious non-synonymous single nucleotide polymorphism (SNPs) aids in the assessment of genetic basis of diseases and prediction of clinical phenotypes. In this study, data obtained from whole exome sequencing of Vechur cow using Illumina HiSeq 2500 platform is compared with that of crossbred cattle of Kerala. Sequence analysis of selected 18 mastitis resistant genes, evaluated the consequence of non-synonymous SNPs in these genes from both Vechur and crossbred cattle of Kerala, using sequence and structure-based computational tools such as SIFT, PROVEAN and I-MUTANT 2.0. Compared to Vechur cattle, incidence of missense deleterious mutation to effect protein functioning were relatively higher in crossbred cattle. These results on the type of genetic variants and its impact on normal functioning of a protein will assist to predict and enhance the disease resistance in cattle breeds.

Association of polymorphisms of the β-defensin 1 gene with nematode and protozoan infection traits in goat

This study's purpose was to identify polymorphisms (SNP) in the goat β-defensin 1 gene and to associate these SNPs with traits related to nematodean and protozoan infections in Anglo-Nubian goats from semiarid region of Brazil. A total of 184 animals were used for DNA extraction, PCR and DNA automatic sequencing. The association analyses included the fixed effects of animal age, bloodline and genotype of the SNP marker in the statistical model. The means of genotypes were compared by the Fisher test (P < 0.05). Twelve polymorphism genotypes were found: two in intron 1, seven in exon 2 and three in 3' untranslated region. The SNPs of exon 2 were responsible for amino acid substitutions in six genetic codes, and the changes in the 25th and 33rd codes affected the protein function. The SNP 1937 was significantly associated with number of protozoan oocysts, whereas SNP 2001 was associated with degree of anaemia (Famacha©). Polymorphism 2046, in turn, showed a significant association with Famacha© degree and number of protozoan oocysts. SNP 2140 associated with maximum EPG of the animal. Results from this study suggest that the β-defensin 1 gene can be used as a molecular marker for selection of goats regarding the susceptibility to endoparasites infections.

Polymorphism in ovine ANXA9 gene and the physio-chemical properties and the fraction of protein in milk

BACKGROUND

Annexin A9 (ANXA9) is a specific fatty acid transport protein. The ANXA9 gene is expressed in various tissues, including secretory tissue and the mammary glands. The association between the three single nucleotide polymorphisms (SNPs) of the ANXA9 gene and sheep's milk composition was assessed.

RESULTS

Genotype analysis was performed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The ANXA9 polymorphisms that were studied had the following major allele frequencies (MAFs): SNP1: allele G 0,66; SNP2: allele G 0,54; SNP3: allele C 0,57. The study found the most favorable profile of protein fractions, namely increased kappa-casein fractions and a decreased level of whey protein in sheep's milk for the SNP1 and SNP3 polymorphisms. Sheep with the SNP1 GA genotype had the highest (P < 0.05) content of fat and dry matter in milk. AXNA9 gene polymorphism did not influence the levels of protein, lactose, or urea in sheep's milk.

CONCLUSION

The information contained in this study may be useful for determining the impact of the ANXA9 gene on sheep's milk. The ANXA9 SNP1 and SNP3 polymorphism results could be included in breeding programs to select sheep with the genotypes ensuring the highest kappa-casein levels in milk. However, it is worth conducting further research on ANXA9 and milk composition in larger herds of animals and various breeds of sheep. © 2018 Society of Chemical Industry.

Full-length sequencing and identification of novel polymorphisms in the ACACA gene of Valle del Belice sheep breed

The essential role of the acetyl-CoA carboxylase (ACACA) enzyme in milk fatty acid (FA) synthesis suggests that it may be responsible for the phenotypic variability observed inmilk.Before attempting association analyses between this gene and/or enzyme and phenotypic traits, a study on the genetic variability within this locus is required. The aim of this work was to sequence the entire coding region of ACACA gene in Valle del Belice sheep breed to identify polymorphic sites. A total of 51 coding exons of ACACA gene were sequenced in 32 individuals of Valle del Belice sheep breed. Sequencing analysis and alignment of obtained sequences showed the presence of 23 polymorphic sites. The most polymorphic was exon 53 which showed presence of 12 single-nucleotide polymorphisms (SNPs), ofwhich eightweremissensemutations, caused amino acid changes and therefore may affect protein function or stability causing variation in phenotype. The identified polymorphisms showed high variability of the ACACA gene. Sequences analysis allowed to find six new SNPs in exon 53 (6832C>T; 6835C>A; 6840G>A; 6847G>T; 6852C>T and 6860G>C). A total of 31 haplotypes were inferred. Although this study could not provide association study with production traits, it shows finding of novel SNPs that might be important in future studies and laid the basis for further association analyses needed to evaluate the potential use of these SNPs as genetic markers for fat content and FAs composition in milk of Valle del Belice sheep breed.