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Buffalo production is spreading globally because of its economic advantage. Then, it has become necessary to improve the reproductive and productive efficiency of these animals, as well as to look for genetic factors that increase this efficiency. The objectives of this study were to characterize the promoter region of the melatonin 1A receptor gene (MTRN1A), to detect possible SNPs and associate them with fertility characteristics, and identify binding sites of transcription factors involved in the regulation of genetic expression in buffaloes in the Amazon. The conventional PCR method was carried out using the two primers designed from the reference sequence deposited in the GenBank AY52466.1. The products of the PCRs were purified, sequenced, and subsequently edited and aligned. Twenty-six SNPs were found, where 73% presented allele frequencies of wild nucleotides above 0.5, and 73% presented deviations from the Hardy-Weinberg equilibrium (P < 0.05) and F IS varying between 0.06 and 1.00, characterizing high degrees of inbreeding within the population. A block of ACAA deletion (position -1483) was observed in 25% of samples. The associations between these SNPs and reproductive characteristics were observed for calving interval and 5 SNPs: -1289, -1139, -911, -724, and -656 (P < 0.05), and three other SNPs: -1395, -724, and -94 (P < 0.05) were associated significantly with age at first calving, and were not associated with calving concentration. The promoter region was characterized by the different types of binding factors, where only 11 sites are significantly strong enough for transcription factor bindings. The ACAA deletion also exhibited a strong association with transcription factors. As a result, it would be necessary to test the SNPs above with other reproductive characteristics of economic relevance to approve the gene as a strong candidate for the selection of buffaloes in the Amazon.

The objective of this study was to sequence part of the exon 1 in the melatonin receptor 1A gene (MTRN1A) in buffaloes to detect a novel polymorphism with which to associate reproductive characteristics, such as age at first birth and the interval between births, in buffaloes from the northeastern region of the State of Pará (Brazil). Buffalo hair samples (77) were collected from the Terra Firme region of Pará. DNA was extracted and polymerase chain reactions (PCRs) were carried out with a primer that was designed using the GenBank accession No. AY524665 reference sequence. PCR products were purified and sequenced. After editing and analysis of the sequences, a mutation was observed at the 62nd position in exon 1 of MTRN1A (T↔C), which corresponded with a change in the 21st amino acid from leucine to proline. All possible genotypes were observed, with the most common being genotype CC (0.481). The allele frequencies were T = 0.377 and C = 0.623. Statistical analysis of FIS showed inbreeding within the sample group (FIS = 0.397) and deviations from the Hardy- Weinberg equilibrium were observed (P < 0.05). Associations between genotypes and reproductive characteristics were not significant (P > 0.05). Although the related SNP was not synonymous, there were no observable effects on the reproductive characteristics under investigation. As such, it would be ideal to detect other SNPs in exon 1 of the MTRN1A gene that can be associated with reproductive characteristics in Amazonian buffaloes.

The correction is only in the name of the first author and should be: E.M. Barbosa(1), B.B. Souza(2), R.C. Guimarães(2), J.S.N. Azevedo(3), E.C. Gonçalves(4), H.F.L. Ribeiro(2), S.T. Rolim Filho(2), E. Silva Filho(2).

Buffalo farming in Brazil is increasing, as is the challenge of identifying molecular markers that will improve productivity. Therefore, the aim of this study was to analyze single nucleotide polymorphisms of the receptor gene for the hormone melatonin in buffaloes from northern Brazil by polymerase chain reactions (PCRs) and restriction fragment length polymorphism assays. The PCR products exhibited a cutting point for HpaI at the 318th position of the gene, indicating a transition substitution (T↔C). This substitution was synonymic, and did not alter the stability of the mRNA structure. Allelic and genotypic frequencies differed between the populations studied, and all of the populations demonstrated endogamy and were in Hardy-Weinberg equilibrium. Therefore, the HpaI restriction marker in the melatonin receptor gene cannot be used for genetic improvement, but is an excellent marker for population genetic studies.

β-defensins are capable of creating pores in the bacterial membrane. In this study, we aim to determine the structure of 3 different sheep β-defensin 2 (SBD-2) sequences by molecular modeling. A herd of 47 sheep from the Centre for Ovine and Caprine Research of Pará was selected for this investigation. The AA, AG, and GG alleles were found on β-defensin sequences. We used homology modeling and molecular dynamic simulations to generate 3D models of peptides and they were successfully validated. The proteins are structurally very similar to classic defensins composed of 3 β-sheets and 3 disulfide bonds. Variations in the organization of the tertiary structure and distribution of charged residues were found between AA, AG, and GG alleles. In this study, we were able to characterize and show the structure of 3 SBD-2 gene variants for the first time in Amazonian sheep. Results demonstrated that these variants are similar in structures to classic β-defensins, but contain more positives charges, which may indicate an increase in efficacy.

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.