Vitamin D has been considered a strong contributing factor to type 1 diabetes mellitus (T1DM). Many studies have investigated polymorphisms in the VDR gene in association with T1DM in different populations, but there are still conflicting findings. This study aimed to evaluate the association of four variants in the VDR gene (rs7975232, rs1544410, rs731236, and rs2228570) with T1DM risk and vitamin D levels within a population from North Region, Brazil, as well as the influence of genomic ancestry on T1DM. A total of 65 T1DM patients and 83 non-T1DM patients were enrolled in this study. VDR gene polymorphisms were assessed using Sanger sequencing analysis. Genomic ancestry was analyzed using a set of 61 ancestry-informative markers. T1DM patients showed higher European genomic contribution and lower Native American genomic contribution when compared to non-T1DM patients. T1DM patients with AA genotype in rs1544410 or CC genotype in rs731236 had significantly lower 25(OH)D levels compared to the other two genotypes (p = 0.013 and p = 0.02, respectively), while T1DM with TT genotype in rs2228570 had higher 25(OH)D levels compared to CC + TC in the same polymorphism (p = 0.011). Our findings suggest that the association between 25(OH)D and T1DM may be modified by VDR variants, possibly influencing the development of this autoimmune disease.

The Amazonian symbol fish Arapaima gigas is the only living representative of the Arapamidae family. Environmental pressures and illegal fishing threaten the species’ survival. To protect wild populations, a national regulation must be developed for the management of A. gigas throughout the Amazon basin. Moreover, the reproductive genetic management and recruitment of additional founders by aquaculture farms are needed to mitigate the damage caused by domestication. To contribute to the sustainable development, we investigated the genetic diversity of wild and cultivated populations of A. gigas and developed a panel composed by 12 microsatellite markers for individual and population genetic tracing. We analyzed 368 samples from three wild and four farmed populations. The results revealed low rates of genetic diversity in all populations, loss of genetic diversity and high inbreeding rates in farmed populations, and genetic structuring among wild and farmed populations. Genetic tracing using the 12 microsatellite markers was effective, and presented a better performance in identifying samples at the population level. The 12-microsatellite panel is appliable to the legal aspects of the trade of the A. gigas, such as origin discrimination, reproductive genetic management by DNA profiling, and evaluation and monitoring of genetic diversity.

The objective of this study was to determine factors affecting phenotypic characteristics related to milk production and reproductive efficiency of dairy buffalo. Phenotypic records of 2,459 Murrah, Mediterranean and crossbred buffaloes from the Embrapa Eastern Amazônia herd, from 1969 to 2013 were used. Traits included: total milk production during lactation (TMP), milk production corrected for 305 days (P305); cow weight at calving (CW), fat milk percentage (F), age at first calving (AFC), calving interval (CI), calf birth weight (BW), as well as lactation (LP) and service periods (SP). Most traits were affected by genetic group as well as year and season or interaction between them. Genetic group affected F, CI, SP and CW. Very young and older cows showed poorer production traits. There was interaction between season and year for F, CI and CW. Correlations traits were generally medium to low. The principal component analysis showed that higher fat milk percentage was associated with higher percentage of Murrah breed, longer lactation period and older cows. Phenotypic characteristics in buffaloes reared in the Brazilian Amazon were significantly affected by genetic and management factors. This information can be used to help build sustainable production systems for the region and guide farmer decisions.

Water buffaloes (Bubalus bubalis) are quite well adapted to climatic conditions in the Amazon, and in this biome, they are noted for the considerable amount of meat and milk they produce and how hard they are able to work. Because of a lack of research dedicated to improving the rearing of buffaloes in the Amazon, the objective of this study was to genetically characterize the Murrah and Mediterranean breeds, as well as a mixed-breed population, based on polymorphisms in the diacylglycerol O-acyltransferase 1 gene (DGAT1), and associate the genotypes with milk production. By using the polymerase chain reaction-single-strand conformation polymorphism technique, the alleles A (0.79), B (0.20), and D (0.01) were found in the Murrah breed. In the Mediterranean and mixed-breed buffaloes, we found alleles A (0.69) and (0.77) and B (0.31) and (0.23), respectively. The Murrah breed had the genotypes AA (0.63), AB (0.29), BB (0.05), and AD (0.03), and the Mediterranean and mixed-breed buffaloes had the genotypes AA (0.44) and (0.61), AB (0.50) and (0.31), and BB (0.06) and (0.08), respectively. For the Murrah, Mediterranean, and mixed-breed buffaloes, respectively, the expected heterozygosity values were 0.34, 0.43, and 0.35, the inbreeding coefficients were 0.78, -0.15, and 0.17, and the Hardy-Weinberg probabilities were 0.70, 0.67, and 0.52. The genotypes evaluated did not have an effect on milk production; however, the single nucleotide polymorphisms can be used in studies on genetic variability.

Hyphessobrycon heterorhabdus (Ulrey, 1894), popularly known as ‘Flag Tetra’ in English speaking countries, belongs to the genus Hyphessobrycon of the family Characidae, and is widely present in the eastern Amazon basin. Here, using Illumina sequencing, we report the complete mitogenome sequence of H. heterorhabdus. Overall, the mitogenome has 17,021 bp, containing 13 protein-coding, 22 tRNA, and 2 rRNA genes. Non-ambiguous nucleotide compositions of the H. heterorhabdus mitogenome are A: 29.2%, T: 29.4%, G: 15.6%, and C: 25.8%. As recently indicated, the phylogenetic analyses did not support four separate genera (Hemigrammus, Hyphessobrycon, Moenkhausia, and Psalidodon) of Characidae. Understanding the H. heterorhabdus mitogenome is important for taxonomic purposes as well as for the molecular characterization of environmental pollutants. Thus, the mitogenome described here will be a valuable resource for studies on environmental changes, evolutionary genetics, species delimitation, and phylogenetic analyses in Characidae.

The objective of this study was to evaluate genetic aspects related to production and reproductive efficiency of Murrah and Mediterranean buffaloes and their crosses. A ranking of bulls from Embrapa Eastern Amazonia was also composed to guide assisted mating. Birth records of 2,322 Murrah, Mediterranean, and crossbred buffaloes from the Embrapa Eastern Amazon herd, from 1953 to 2013, as well as information on production and reproductive traits were used. Genetic analyzes were performed in the WOMBAT software using the animal model with two-trait analysis. While heritability (h²) for total milk production (TMP) and fat milk percentage (F) were generally high, for reproductive traits h² tended to be low. Genetic correlations for TMP with the other traits were low and negative, except for TMP with calving interval (CI) and service period (SP) in the Mediterranean breed and with age at first calving (AFC) and SP in crossbred, which were positive and high. Bull 1001 had high predicted transmitting ability (PTA) for TMP, so it should transmit a greater volume of milk to his offspring, although it had a lower PTA for F. There was sufficient variability within the herd to work with genetic management for both production and reproductive efficiency.