Genetic polymorphisms in β-defensin II gene in Amazon sheep from Brazil

Abstract

The northern region of Brazil produces a large number of sheep, with Pará being the largest sheep breeding state in the region. In the Amazon region, livestock production is a challenge due to the high diversity of pathogens affecting humans and animals. Defensins are antimicrobial peptides acting as a first barrier against micro-organisms and present high variation in different organisms. The objective of this study was to detect polymorphisms in exon II in β-defensin II in Amazon sheep. The gene was amplified by PCR from DNA extracted from 47 sheep blood samples from the Santa Inês breed. Products were sequenced, aligned and analyzed. Three single nucleotide polymorphism (SNP) positions were observed with transition substitutions (A↔G) at positions 1643, 1659, and 1750. The 1643 and 1750 SNPs showed a low variability and significant deviations from Hardy-Weinberg equilibrium (HWE) (P < 0.05) meanwhile the SNP 1659 showed moderate absence of genetic variability and deviation from HWE (P > 0.05). Polymorphisms at 1643 and 1659 were predicted to modify amino acids in the peptide chain (isoleucine to valine and arginine to lysine, respectively) with no effects on protein function. Results from this study suggest that SNPs are important markers for β-defensin II efficiency studies on the immune system of sheep in the Brazilian Amazon.

Sheep β-Defensin 2 Regulates Escherichia coli F17 Resistance via NF-κB and MAPK Signaling Pathways in Ovine Intestinal Epithelial Cells

“…Thus far, SBD -1 and SBD -2 have been annotated in sheep and are located on chromosome 26. SBD -2 is mainly distributed in the epithelial cells of the gastrointestinal tract and digestive tract [ 17 ]. In recent years, studies focused on sheep β-defensin seem to be more inclined to study SBD -1, because the strong expression of SBD -1 in rumen epithelium makes researchers interested in exploring the mechanism of SBD -1 expression in the process of sheep rumen innate immunity [ 18 , 19 , 20 , 21 , 22 ].…”

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

“…Transitions were A to G and T to C types, respectively. The GBD‐1 gene has been the most polymorphic gene, compared to sheep β‐defensin 1 gene ( SBD‐1 ), as described by Monteleone et al, and to sheep β‐defensin 2 gene ( SBD‐2 ), described by the same authors and Souza et al when analysing a sheep herd from Amazon.…”

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

“…Few studies have been conducted on ␤-defensin genes in sheep. However, Souza et al (2015) performed a genotyping study on SBD2 gene in Amazon sheep. Monteleone et al (2011), in a sequencing polymorphisms discovery study on Valle del Belice dairy sheep, reported a total of seven single nucleotide polymorphisms (SNPs), two in SBD1 and five in SBD2 genes.…”