Genetic polymorphisms in ß-defensin II gene in Amazon sheep from Brazil.

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 ß-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 ß-defensin II efficiency studies on the immune system of sheep in the Brazilian Amazon.

Genetic characterization of Curraleiro Pé-Duro bovine breed from a conservation herd of Brazilian semiarid.

Curraleiro Pé-Duro is a rustic bovine taurine breed found in Northeast of Brazil; this breed has decreased its production potentially in order to adapt to the region environment conditions. Consequently, it is under risk of extinction and is maintained at a preservation center in Piauí State, Brazil, as a source of genetic material adapted to local conditions. We analyzed genetic variability of this breed using microsatellite markers. Sixty animals were genotyped using 11 microsatellite loci normally used for paternity tests in bovines. The observed number of alleles ranged from 5 to 9, and the effective number of alleles ranged from 2.01 to 4.64. The Shannon index ranged from 0.949 to 1.669. The expected heterozygosity ranged from 0.510 to 0.798. Polymorphism information content values ranged from 0.453 to 0.751. Divergence from Hardy-Weinberg equilibrium was significant and the mean FIS value was 0.010. We conclude that this breed still has some genetic diversity, but with evident risk due to genetic drift caused by current breeding management. It will be necessary to insert animals from other herds to obtain the desired level of genetic variability in this breed remnant.