Characterization of intronic SNP located in candidate genes influencing cattle temperament

The objective of this study was to evaluate the effect of intronic single nucleotide polymorphisms (SNP) on temperament traits in a Brahman cattle population. The SNP located in CACNG4, EXOC4, NRXN3, and SLC9A4 candidate genes were genotyped in 250 animals with temperament records of exit velocity, pen score, and temperament score. Rs3423464051:G>A in the CACNG4 gene was associated with exit velocity and temperament score. An in silico analysis of the five intronic SNP showed that alternative alleles of CACNG4-rs3423464051, EXOC4-rs109393235, and SLC9A4-rs109722627 SNP could alter branch point sites during splicing, while a protein-protein interaction network analysis demonstrated a GRIA2 gene-mediated interaction between CACNG4 and NRXN3. The present results support previously reported evidence regarding bovine temperament-related candidate genes, particularly CACNG4, which is a confirmed candidate gene in need of more detailed analyses to reveal its role in temperament-related traits.(AU)

Morphology, morpho-taxometric and molecular characterization of the invasive alien species Caribbean leatherleaf slug Sarasinula plebeia (Gastropoda: Veronicellidae): a first record in southern Philippines

Herein, we first report the comprehensive description of the terrestrial slug, Sarasinula plebeia (Gastropoda: Veronicellidae) by employing morphology, morpho­taxometrics and molecular analysis. A rapid survey on terrestrial slug inva­sive alien species (IAS) was conducted in La Dicha, Malangas, Zamboanga Sibugay, the Philippines. Obtained COI gene sequenc­es shared 100% similarities to S. plebeia from Brazil (JX532107, KM489378), Dominica (KM489500) and Vietnam (KM489367) and further supported using Bayesian analysis thus designated as S. plebeia isolate LDZS. Notably, the first reported S. plebe-ia in 2013 from Batan island, Batanes, northern Philippines, characterized through COI gene markers (JQ582277, JQ582278, JQ582279) showed 100% sequence similarities to a closely related veronicellid slug, Laevecaulisalte isolates (LC636101, LC636102, LC636103, and LC636104) from Japan. Taken this into account, our S. plebeia LDZS isolated from an agricultural field is the first report in the Philippines with combined diagnostic tools for the taxon.(AU)

Mapping of leaf rust resistance genes in common wheat 'Guinong08-6' / Mapa de genes de resistência à ferrugem da folha em trigo 'Guinong08-6'

Wheat leaf rust (Puccinia triticina Eriks.), a devastating disease of wheat in the world, causes severe yield losses and therefore the development of resistant cultivars is very important. Here, a Chinese wheat line (Guinong08-6) showed adult-plant resistance against mixed fungal isolates of leaf rust, which is common in Guiyang region. It was crossed with a susceptible wheat line (Guinong19) to develop F1, F2, and F3 hybrids. Combined SSR and STS markers were used to map leaf rust resistance genes in Guinong08-6, and the resistance phenotype of Guinong08-6 was co-regulated by two complementary dominant genes, named LrGn08-6A and LrGn08-6B. LrGn08-6A was mapped to chromosome 2AS with markers URIC-LN2 and Xgpw2204, which flanked the gene at distances of 1.8 centimorgan (cM) and 14.83 cM, respectively. LrGn08-6B was mapped to chromosome 4DL with markers Xgpw342 and Xbarc93, which both flanked the gene at a distance of 26.57 cM. Genetic and molecular marker analyses demonstrated that LrGn08-6A, which was inherited from Aegilops ventricosa may be the resistance gene Lr37, while LrGn08-6B may be a newly discovered leaf rust resistance gene.(AU)

A ferrugem da folha do trigo (Puccinia triticina Eriks.), importante doença do trigo em todo o mundo, causa graves perdas de rendimento e, portanto, o desenvolvimento de cultivares resistentes é muito importante. Nesta pesquisa, uma linhagem chinesa de trigo (Guinong08-6) mostrou resistência de plantas adultas a uma mistura de isolados do patógeno, na região de Guiyang, China. Essa linhagem foi cruzada com uma linhagem suscetível de trigo (Guinong19) para desenvolver híbridos F1, F2 e F3. Combinados de marcadores SSR e STS foram usados para mapear genes de resistência à ferrugem da folha em Guinong08-6, e o fenótipo de resistência de Guinong08-6 foi co-regulado por dois genes dominantes complementares, chamados LrGn08-6A e LrGn08-6B. LrGn08-6A foi mapeado para o cromossomo 2AS com marcadores URIC-LN2 e Xgpw2204, que flanquearam o gene em distâncias de 1,8 centimorgano (cM) e 14,83 cM, respectivamente. LrGn08-6B foi mapeado para o cromossomo 4DL com marcadores Xgpw342 e Xbarc93, e ambos flanquearam o gene a uma distância de 26,57 cM. As análises genéticas e moleculares de marcadores demonstraram que LrGn08-6A, que foi herdado de Aegilops ventricosa, pode ser o gene de resistência Lr37, enquanto LrGn08-6B pode ser um gene recentemente descoberto de resistência à ferrugem da folha do trigo.(AU)

Identification of SCAR markers for genetic authentication of Dendrobium nobile Lindl / Identificação de marcadores SCAR para autenticação genética de Dendrobium nobile Lindl

Dendrobium nobile Lindl. is an orcid plant with important medicinal values. This is a colourful houseplant, and also a popular herb in traditional Chinese medicine (TCM). The variants of this plant from different geographic regions might be high, and in this study, we aimed to develop specific sequence characterized amplified region (SCAR) markers for the identification of specific variant of this plant. Different cultivars of D. nobile were collected from nine different places of China, and one cultivar from Myanmar. DNA materials were extracted from the plant samples, random amplified polymorphic DNA (RAPD) were developed, cloned and sequenced for the development of SCAR markers. We have developed four SCAR markers, which are specific to the cultivar from Luzhou China, and clearly distinguishable (genetically) from other cultivars. These SCAR markers are deposited in GenBank (accession number MZ417502, MZ484089, MZ417504 and MZ417505). Four SCAR markers for D. nobile are effective molecular technique to genetically identify the different cultivars or species, and this method is applicable for genetic characterization and identification of other plant species too.

Dendrobium nobile Lindl. é uma orquídea com importantes valores medicinais. Esta é uma colorida planta doméstica e também uma erva popular na Medicina Tradicional Chinesa (MTC). As variantes desta planta de diferentes regiões geográficas podem ser altas, e neste estudo, nosso objetivo foi desenvolver marcadores de região amplificada de sequência caracterizada (in English, Sequence Characterized Amplified Region (SCAR)) para a identificação de variante específica desta planta. Diferentes cultivares de D. nobile foram coletadas de nove locais diferentes da China e uma cultivar de Mianmar. Materiais de DNA foram extraídos das amostras de plantas, em que a Amplificação Aleatória de DNA Polimórfico (in English, Random Amplified Polymorphism DNA (RAPD)) foi desenvolvida, clonada e sequenciada para o desenvolvimento de marcadores SCAR. Desenvolvemos quatro marcadores SCAR, que são específicos para a cultivar de Luzhou na China e claramente distinguíveis (geneticamente) de outras cultivares. Esses marcadores SCAR estão depositados no GenBank (números de acesso MZ417502, MZ484089, MZ417504 e MZ417505). Quatro marcadores SCAR para D. nobile compreendem técnicas moleculares eficazes para identificar geneticamente as diferentes cultivares ou espécies, e este método é aplicável para caracterização genética e identificação de outras espécies de plantas também.

Molecular classification and comparative phylogeographic study of insectivorous bat species (Pipisitrellus coromandra) from Punjab, Pakistan / Classificação molecular e estudo filogeográfico comparativo de espécies de morcegos insetívoros (Pipistrellus coromandra) de Punjab, Paquistão

Molecular based identification of bat fauna in Pakistan has been relatively less explored. The current study was therefore planned to report for the first time the molecular classification of insectivorous bats (Pipistrellus coromandra) based on mitochondrion gene (COI) from Punjab, Pakistan. Specimens were collected from five different locations followed by DNA extraction with subsequent gene amplification and sequencing. All samples in the study had shown close identity matches with species (Pipistrellus coromandra) from India and (Pipistrellus tenuis) from Vietnam with percentage identity score of 96.11 and 95.58 respectively except one sequence which only revealed 86.78% identity match on Basic Local Alignment Search Tool (BLAST) and could only be assigned to genus level Pipistrellus sp. The results indicated negligible intra-population genetic distance among collected samples whereas the comparison with species from other countries had shown high intraspecific (P. coromandra) and interspecific (P. tenuis) mean genetic distances. The current study hence successfully proved the efficiency of COI gene as a molecular marker for species identification and in analyzing the patterns of genetic variation with species from other countries.

A identificação com base molecular da fauna de morcegos no Paquistão tem sido relativamente menos explorada. Portanto, o estudo atual foi planejado para relatar pela primeira vez a classificação molecular de morcegos insetívoros (Pipistrellus coromandra) com base no gene da mitocôndria (COI) de Punjab, Paquistão. As amostras foram coletadas em cinco locais diferentes, seguidas pela extração de DNA com subsequente amplificação e sequenciamento do gene. Todas as amostras no estudo mostraram coincidências de identidade próximas com espécies (Pipistrellus coromandra) da Índia e (Pipistrellus tenuis) do Vietnã, com pontuação de identidade percentual de 96,11 e 95,58, respectivamente, exceto uma sequência que revelou apenas 86,78% de correspondência de identidade na Ferramenta de Pesquisa de Alinhamento Local Básico (BLAST), a qual só poderia ser atribuída ao nível de gênero Pipistrellus sp. Os resultados indicaram distância genética intrapopulacional desprezível entre as amostras coletadas, enquanto a comparação com espécies de outros países mostrou altas distâncias genéticas intraespecíficas (P. coromandra) e interespecíficas (P. tenuis) médias. O presente estudo, portanto, comprovou com sucesso a eficiência do gene COI como marcador molecular para identificação de espécies e análise dos padrões de variação genética com espécies de outros países.

Molecular classification and comparative phylogeographic study of insectivorous bat species (Pipisitrellus coromandra) from Punjab, Pakistan / Classificação molecular e estudo filogeográfico comparativo de espécies de morcegos insetívoros (Pipistrellus coromandra) de Punjab, Paquistão

Molecular based identification of bat fauna in Pakistan has been relatively less explored. The current study was therefore planned to report for the first time the molecular classification of insectivorous bats (Pipistrellus coromandra) based on mitochondrion gene (COI) from Punjab, Pakistan. Specimens were collected from five different locations followed by DNA extraction with subsequent gene amplification and sequencing. All samples in the study had shown close identity matches with species (Pipistrellus coromandra) from India and (Pipistrellus tenuis) from Vietnam with percentage identity score of 96.11 and 95.58 respectively except one sequence which only revealed 86.78% identity match on Basic Local Alignment Search Tool (BLAST) and could only be assigned to genus level Pipistrellus sp. The results indicated negligible intra-population genetic distance among collected samples whereas the comparison with species from other countries had shown high intraspecific (P. coromandra) and interspecific (P. tenuis) mean genetic distances. The current study hence successfully proved the efficiency of COI gene as a molecular marker for species identification and in analyzing the patterns of genetic variation with species from other countries.(AU)

A identificação com base molecular da fauna de morcegos no Paquistão tem sido relativamente menos explorada. Portanto, o estudo atual foi planejado para relatar pela primeira vez a classificação molecular de morcegos insetívoros (Pipistrellus coromandra) com base no gene da mitocôndria (COI) de Punjab, Paquistão. As amostras foram coletadas em cinco locais diferentes, seguidas pela extração de DNA com subsequente amplificação e sequenciamento do gene. Todas as amostras no estudo mostraram coincidências de identidade próximas com espécies (Pipistrellus coromandra) da Índia e (Pipistrellus tenuis) do Vietnã, com pontuação de identidade percentual de 96,11 e 95,58, respectivamente, exceto uma sequência que revelou apenas 86,78% de correspondência de identidade na Ferramenta de Pesquisa de Alinhamento Local Básico (BLAST), a qual só poderia ser atribuída ao nível de gênero Pipistrellus sp. Os resultados indicaram distância genética intrapopulacional desprezível entre as amostras coletadas, enquanto a comparação com espécies de outros países mostrou altas distâncias genéticas intraespecíficas (P. coromandra) e interespecíficas (P. tenuis) médias. O presente estudo, portanto, comprovou com sucesso a eficiência do gene COI como marcador molecular para identificação de espécies e análise dos padrões de variação genética com espécies de outros países.(AU)

Genetic diversity in Amazonian Jundiá (Leiarius marmoratus) stocks using heterologous primers

With the rise of world fish farming, the national scenario is favorable for using native fish for intensive farming. Among the catfish, the Amazonian Jundiá (Leiarius marmoratus) is a robust candidate, easy to grow and with good organoleptic characteristics in its flesh. For productive success in captivity, it is necessary to consider some questions about the species, such as genetic variability, which must have an acceptable level in a breeding stock, in order to maintain a good diversity; this reduces losses due to inbreeding and low diversity. Therefore, the objective of this study was to characterize the genetic variability of commercial stocks of L. marmoratus from the State of Mato Grosso through microsatellite molecular markers. We analyzed 143 individuals from three stocks. The mean heterozygosity and the inbreeding coefficients observed were 0.060; 0.084; 0.141; and 0.539; 0.562; 0.514, respectively, for the stocks of Campo Verde, Juína, and Nova Mutum. The Deviation in the Hardy-Weinberg equilibrium was observed in most of the loci in the three populations. Considering the genetic differentiation, it is concluded that the three populations are very close genetically, which requires introduction of new genetic material in the stocks to enrich them genetically for a later reproductive program.(AU)

Biobanking and use of gonadal tissues - a promising strategy for conserving wildlife from the Caatinga biome

Biological Resource Banks (BRB) or Genetic Resource Banks (GRB) are critical tools for the conservation of animal biodiversity. According to the International Union for Conservation of Nature, more than 38,500 species are threatened with extinction, out of a total of 138,300 surveyed species. These banks are repositories of biological samples and data recovered and preserved for the long term by zoos, universities, research centers and other conservation organizations. In recent years, BRB have increasingly included ovarian and testicular tissues as additional options to rescue and propagate wild species, especially those at risk of extinction. After in vitro culture or grafting, gonadal tissues are potential sources of matured gametes that can be used for Assisted Reproduction Technologies while informing about gametogenesis or mechanisms involved in infertility. It therefore is crucial to properly recover, cryopreserve, and culture these tissues using species-specific protocols. Developing BRBs is currently one of the strategies to preserve species from the Caatinga biome - an exclusively Brazilian biome with a rich wild fauna that suffers from anthropogenic activities. Among wild species from this biome, studies have been primarily conducted in collared peccaries, agoutis, cavies, and armadillos to preserve their ovarian and testicular tissues. Additionally, domestic species such as the domestic cat and donkeys have been proposed as models for wild species that are phylogenetically close. This review addresses the main technical aspects involved in obtaining BRB derived from gonadal tissues in some wild species of the Caatinga biome. It reports recent advances and perspectives to use these biological materials for wildlife conservation.(AU)

Fit and genetic parameters of the growth curve of Polled Nellore cattle / Ajuste e parâmetros genéticos da curva de crescimento em bovinos da raça Nelore Mocho

This study was undertaken to compare different non-linear models for fitting growth curves of Polled Nellore animals as well as to estimate genetic parameters for the components of the growth curve. The study involved body weight-age data of 6,717 Polled Nellore cattle from birth to 650 days of age, which belonged to the Brazilian Association of Zebu Breeders (ABCZ), corresponding to the period from 1980 to 2011. Four non-linear models (Brody, Bertalanffy, Logistic, and Gompertz) were fitted and compared by the adjusted coefficient of determination (R2adj), mean absolute deviation of residuals (MAD), root mean square error (RMSE), Akaike information criterion (AIC), and Bayesian information criterion (BIC). To estimate the genetic parameters and genetic values of asymptotic weight (A), integration constant (B), and maturation rate (K), the Bayesian inference method was adopted. The Brody model showed the lowest values of MAD, RMSE, AIC, and BIC and the highest R2adj. Heritability estimates for parameters A, B, and K were 0.11, 0.16, and 0.30, respectively, whereas genetic correlations were 0.01 (A-B), -0.91 (A-K), and 0.24 (B-K). The Brody model provided the best fit. The K parameter shows enough genetic variability for selection in the herd. Heavier animals in adulthood tend to exhibit lower growth rates. Despite the low heritability estimate of parameter A, there were genetic gains, indicating that selection is being efficient on asymptotic weight.(AU)

O objetivo deste estudo foi comparar diferentes modelos não lineares para o ajuste das curvas de crescimento de animais da raça Nelore Mocho e estimar os parâmetros genéticos para os componentes da curva de crescimento. Foram utilizados dados de peso corporal-idade do nascimento aos 650 dias de idades de 6.717 bovinos da raça Nelore Mocho, pertencentes à Associação Brasileira de Criadores de Zebu (ABCZ), referentes ao período de 1980 e 2011. Quatro modelos não lineares (Brody, Bertalanffy, Logístico e Gompertz) foram ajustados e comparados pelo coeficiente de determinação ajustado (R2adj), desvio médio absoluto dos resíduos (DMA), raiz quadrada do quadrado médio do resíduo (RMSE), critério de informação de Akaike (AIC) e o critério de informação bayesiano (BIC). Para estimativas dos parâmetros genéticos e valores genéticos do peso assintótico (A), constante de integração (B) e taxa de maturação (K), utilizou-se o método de inferência Bayesiana. O modelo Brody apresentou os menores valores de DMA, RMSE, AIC e BIC e o maior R2adj. As estimativas de herdabilidade foram 0,11; 0,16 e 0,30 para os parâmetros A, B e K, respectivamente, enquanto as correlações genéticas foram de 0,01 (A-B), -0,91 (A-K) e 0,24 (B-K). Constatou-se que o modelo Brody forneceu o melhor ajuste. O parâmetro K apresenta variabilidade genética suficiente para seleção no rebanho. Animais com maior peso na idade adulta tendem a apresentar menores taxas de crescimento. Apesar da baixa estimativa de herdabilidade do parâmetro A, observou-se ganhos genéticos, indicando que a seleção está sendo eficiente sobre o peso assintótico.(AU)

Genome-Wide Association Study on Two Immune-Related Traits in Jinghai Yellow Chicken

This study was designed to discover molecular marker associated with the interferon INF-γ and avian influenza (AI) antibody titer traits in Jinghai Yellow chicken (Gallus gallus). Serum samples were taken from 400 female chickens and the INF-γ concentrations and AI antibody titer levels were measured. A genome-wide association study was carried out using specific-locus amplified fragment (SLAF) sequencing. Bioinformatics analysis was applied to detect single-nucleotide polymorphisms (SNPs) associated with the two traits. After sequencing and quality control, 103,680 SLAFs and 90,961 SNPs were obtained. The 400 samples were divided into 10 subgroups to reduce the effects of group stratification. The Bonferroni adjusted P-value of genome-wide significance was set at 1.87E−06 according to the number of independent SNP markers and linkage disequilibrium blocks. A SNP that was significantly associated with INF-γ concentration was detected in the myomesin 1 (MYOM1) gene on chromosome 2, and another SNPthat was significantly associated with the AI antibody titer level was detected in an RNA methyltransferase gene (Nsun7), which was found to have an important biological function. We propose that MYOM1 and Nsun7 are valuable candidate genes that influence the disease resistance characters of chicken. However, in-depth investigations are needed to determine the essential roles of these genes in poultry disease resistance and their possible application in breeding disease resistant poultry.(AU)

Genome-Wide Association Study of Abdominal Fat in Wenshang Barred Chicken Based on the Slaf-Seq Technology

Chicken abdominal fat (AF) is an economically important trait, and many studies have been conducted on genetic selection for AF. However, previous studies have focused on detecting functional chromosome mutations or regions using gene chips. The present study used the specific-locus amplified fragment sequencing (SLAF-seq) technology to perform a genome-wide association study (GWAS) on purebred Wengshang Barred chicken. A total of 1,286,715 single-nucleotide polymorphisms (SNPs) were detected, and 175,211 SNPs were selected as candidate SNPs for genome-wide association analysis using TASSEL general linear models. Two SNPs markers reached genome-wide significance. Of these, rs7943847, rs127627362 were significantly associated with AF at 120 days. These SNPs are close to eight genes (SLC16A6, ARSG, WIPI1, PRKAR1A, FAM20A, ABCA8, ABCA9, CPQ,). These results would enrich the studies on AF and promote the use of Chinese chicken, especially the Wenshang Barred chicken.(AU)

Cross species amplification and characterization of microsatellite markers in Leporinus friderici (Characiformes, Anostomidae) / Amplificação cruzada e caracterização de marcadores microssatélites em Leporinus friderici (Characiformes, Anostomidae)

Leporinus friderici is a migratory neotropical fish with elevated ecological and economic importance in Brazil. Microsatellite markers are highly important in population genetic studies, management, and conservation programs; however, no markers are available for this species. In this study, seven microsatellite loci, previously developed for Megaleporinus obtusidens, were successfully cross-amplified in L. friderici. Among these loci, five presented moderate to high genetic variability levels, with four to seven alleles per loci and expected heterozygosities varying from ≥ 0.574 to 1.000. These markers represent a valuable tool for the future management and ecological studies involving this species and group of neotropical fishes.(AU)

Leporinus friderici é um peixe neotropical migratório com elevada importância ecológica e econômica no Brasil. Os marcadores microssatélites são conhecidos por sua importância em estudos genéticos populacionais, programas de manejo e conservação, no entanto, não existem marcadores disponíveis para esta espécie. Neste estudo, sete locos microssatélites, previamente desenvolvidos para Megaleporinus obtusidens foram amplificados com sucesso em L. friderici. Dentre esses loci, cinco apresentaram variabilidade genética moderada a alta, com quatro a sete alelos por loci e heterozigosidades esperadas variando de ≥ 0,574 a 1.000. Esses marcadores representam uma ferramenta valiosa para futuros manejos e estudos ecológicos envolvendo esta espécie e este grupo de peixes neotropicais.(AU)

Identification of patterns related to linkage groups or disequilibrium by factor analysis / Identificação de padrões relacionados a grupos de ligação ou de desequilíbrio por análise de fatores

Empirical patterns of linkage disequilibrium (LD) can be used to increase the statistical power of genetic mapping. This study was carried out with the objective of verifying the efficacy of factor analysis (AF) applied to data sets of molecular markers of the SNP type, in order to identify linkage groups and haplotypes blocks. The SNPs data set used was derived from a simulation process of an F2 population, containing 2000 marks with information of 500 individuals. The estimation of the factorial loadings of FA was made in two ways, considering the matrix of distances between the markers (A) and considering the correlation matrix (R). The number of factors (k) to be used was established based on the graph scree-plot and based on the proportion of the total variance explained. Results indicated that matrices A and R lead to similar results. Based on the scree-plot we considered k equal to 10 and the factors interpreted as being representative of the bonding groups. The second criterion led to a number of factors equal to 50, and the factors interpreted as being representative of the haplotypes blocks. This showed the potential of the technique, making it possible to obtain results applicable to any type of population, helping or corroborating the interpretation of genomic studies. The study demonstrated that AF was able to identify patterns of association between markers, identifying subgroups of markers that reflect factor binding groups and also linkage disequilibrium groups.(AU)

Padrões empíricos de desequilíbrio de ligação (LD) podem ser utilizados para aumentar o poder estatístico do mapeamento genético. Este trabalho foi realizado com o objetivo de verificar a eficácia da análise de fatores (AF) aplicada a conjuntos de dados de marcadores moleculares do tipo SNP, visando identificar grupos de ligação e blocos de haplótipos. O conjunto de dados SNPs utilizado foi oriundo de um processo de simulação de uma população F2, contendo 2000 marcas com informações de 500 indivíduos. A estimação das cargas fatoriais (loadings) da AF foi feita de duas formas, considerando a matriz de distâncias entre os marcadores (A) e considerando a matriz de correlação (R). O número de fatores (k) a ser utilizado foi estabelecido com base no gráfico scree-plot e com base na proporção da variância total explicada. Os resultados indicam que as matrizes A e R conduzem a resultados similares. Com base no scree-plot considerou-se k igual a 10 e os fatores interpretados como sendo representativos dos grupos de ligação. O segundo critério conduziu a um número de fatores igual a 50, e os fatores interpretados como sendo representativos dos blocos de haplótipos. Isto mostra o potencial da técnica que permite obter resultados aplicáveis a qualquer tipo de população, corroborando a interpretação de estudos genômicos. O trabalho demonstrou que a AF foi capaz de identificar padrões de associação entre marcadores, identificando subgrupos de marcadores que refletem grupos de ligação fatorial e também grupos de desequilíbrio de ligação.(AU)

Comparison of random regression models, traditional animal model and with the inclusion of molecular markers in the estimation of genetic parameters in Colombian Holstein cattle / Comparação entre modelos de regressão aleatória, modelo animal tradicional e com a inclusão de marcadores moleculares na estimativa de parâmetros genéticos em bovinos da raça Holandesa Colombiana

The use of molecular markers to identify desirable genes in animal production is known as marker-assisted selection. The traditional genetic evaluation model uses the BLUP methodology; when genetic markers are included in the evaluation model, the methodology is known as M-BLUP. In contrast, random regression models (RRM), unlike the models based on production at 305 days, consider factors that change for each animal from one test to another. The objective of this study was to compare variance components, genetic parameters and breeding values for milk production, protein percentage and somatic cell score in Colombian Holstein cattle using BLUP, M-BLUP and RRM. For the estimation of genetic parameters and values, 2003 lactations corresponding to 1417 cows in 55 herds were used, and effects of the order of delivery, herd, and contemporary group were included. The three traits presented greater heritability under the MBLUP model: 0.44 for protein percentage, 0.27 for milk production and 0.28 for somatic cell score. This was because the genetic variance was greater when M-BLUP was used, which allowed a greater accuracy of the breeding value estimation in the three traits. Therefore, the model that includes information on molecular markers is more suitable for genetic evaluation in Colombian Holstein cattle.(AU)

O uso de marcadores moleculares para identificar genes desejáveis na produção animal é conhecido como seleção assistida por marcadores. O modelo tradicional de avaliação genética utiliza a metodologia BLUP, e quando os marcadores genéticos são incluídos no modelo de avaliação, a metodologia é conhecida como M-BLUP. Por outro lado, os modelos de regressão aleatória (RRM), ao contrário dos modelos baseados em produções a 305 dias, consideram fatores que mudam para cada indivíduo de um controle para outro. O objetivo deste estudo foi comparar componentes de variância, parâmetros e valores genéticos para produção de leite, percentagem de proteína e escore de células somáticas em gado holandês de Colômbia utilizando BLUP, M-BLUP e RRM. Para a estimativa de parâmetros e valores genéticos, foram utilizadas 2.003 lactações correspondentes a 1.417 vacas de 55 rebanhos e efeitos da ordem de parto, rebanho e grupo contemporâneo. Os três traços apresentaram maior hereditariedade no modelo MBLUP, 0,44 para percentagem de proteína, 0,27 para produção de leite e 0,28 para escore de células somáticas. Isso por causa da variância genética foi maior quando o M-BLUP foi utilizado, o que permitiu estimar maior precisão do valor genético nos três traços, portanto, o modelo que inclui informações sobre marcadores moleculares é mais adequado para avaliação genética em gado holandês colombiano.(AU)

Evidence of cytogenetic and histological damage in specimens of Astyanax lacustris (Pisces, Characidae) exposed to the hydrogen cyanide-based herbicide Dormex®

The herbicide Dormex®, a solution of hydrogen cyanamide, is a growth regulator capable of breaking the dormancy of fruit plants, and is commonly applied in agriculture. However, the biological effects of this product on non-target organisms are unknown. The present study investigated the biological response of Astyanax lacustris (Lütken, 1875) specimens exposed to Dormex® using a chromosome aberration test, the mitotic index, and the histological analysis of the gills. Forty specimens of Astyanax lacustris were obtained from a local breeding facility and divided into 10 groups (nine experimental and one control) with four fish in each aquarium (group). The control group was maintained for 24 hours in dechlorinated water while the experimental groups were allocated to one of nine different treatments, with three concentrations of Dormex®, 0.05, 0.1 and 0.5 mL L-1, and exposure for 24, 48 and 72 hours. The fish exposed to Dormex® presented chromosomal aberrations of a number of types, including chromosomal breaks, acentric fragments, decondensation, and gaps at the three Dormex® concentrations, at all exposure times. The mitotic index decreased significantly in comparison with the control group. The histological preparations of the gills revealed alterations such as hyperplasia, and lamellar fusion and edema, whereas in the control group the structure of the gills was preserved. The cytogenetic analysis revealed the genotoxic potential of the herbicide Dormex® and the morphological alterations of the gills demonstrated the sensitivity of the fish, which responded rapidly to the stressor. These findings reinforce the need for special care and restrictions on the use of these herbicides in agricultural areas located near aquatic environments.

Evidence of cytogenetic and histological damage in specimens of Astyanax lacustris (Pisces, Characidae) exposed to the hydrogen cyanide-based herbicide Dormex®

The herbicide Dormex®, a solution of hydrogen cyanamide, is a growth regulator capable of breaking the dormancy of fruit plants, and is commonly applied in agriculture. However, the biological effects of this product on non-target organisms are unknown. The present study investigated the biological response of Astyanax lacustris (Lütken, 1875) specimens exposed to Dormex® using a chromosome aberration test, the mitotic index, and the histological analysis of the gills. Forty specimens of Astyanax lacustris were obtained from a local breeding facility and divided into 10 groups (nine experimental and one control) with four fish in each aquarium (group). The control group was maintained for 24 hours in dechlorinated water while the experimental groups were allocated to one of nine different treatments, with three concentrations of Dormex®, 0.05, 0.1 and 0.5 mL L-1, and exposure for 24, 48 and 72 hours. The fish exposed to Dormex® presented chromosomal aberrations of a number of types, including chromosomal breaks, acentric fragments, decondensation, and gaps at the three Dormex® concentrations, at all exposure times. The mitotic index decreased significantly in comparison with the control group. The histological preparations of the gills revealed alterations such as hyperplasia, and lamellar fusion and edema, whereas in the control group the structure of the gills was preserved. The cytogenetic analysis revealed the genotoxic potential of the herbicide Dormex® and the morphological alterations of the gills demonstrated the sensitivity of the fish, which responded rapidly to the stressor. These findings reinforce the need for special care and restrictions on the use of these herbicides in agricultural areas located near aquatic environments.(AU)

Chromosomal analysis of Centromochlus heckelii (Siluriformes: Auchenipteridae), with a contribution to Centromochlus definition

Historically, there are divergences in the species allocation between Centromochlus and Tatia. This study aimed to generate the first cytogenetic data about Centromochlus and, by analyzing a population of Centromochlus heckelii from the Amazon River basin, to contribute as evidence to a historical taxonomic dilemma. Diploid number of 46 chromosomes and a heteromorphic pair was found in the female karyotypes, thus characterizing a ZZ/ZW sex chromosome system. Pale blocks of heterochromatin were located in centromeric regions of some chromosomes; however, the exclusive female chromosome (W) is almost entirely heterochromatic. AgNORs were detected in terminal position on the short arms of one acrocentric pair in males and two chromosome pairs in females, the acrocentric plus the sex chromosome pair. Notable differences between Centromochlus heckelii and previous data about species of Tatia are: lower diploid number, presence of a sex chromosome system and multiple AgNORs in Centromochlus, while species of Tatia have simple AgNORs and the absence of acrocentric chromosomes. Results in this study show that chromosomal markers could contribute as evidence to taxonomic delimitation studies.(AU)

Historicamente, há divergências na alocação de espécies entre Centromochlus e Tatia. Este estudo teve como objetivo gerar os primeiros dados citogenéticos para Centromochlus e, através da análise de uma população de Centromochlus heckelii da bacia do rio Amazonas, contribuir como evidência para o dilema histórico taxonômico. Foi encontrado o número diploide de 46 cromossomos e um par heteromórfico nos cariótipos das fêmeas, o que caracteriza um sistema sexual ZZ/ZW. Blocos pálidos de heterocromatina foram localizados na região centromérica de alguns cromossomos; no entanto, o cromossomo exclusivo das fêmeas (W) se apresenta quase todo heterocromático. As AgRONs foram detectadas na posição terminal do braço curto de um par acrocêntrico nos machos e em dois pares cromossômicos nas fêmeas, um par de cromossomos acrocêntricos e o par sexual. Notáveis diferenças entre os dados cromossômicos de Centromochlus heckelii e os dados anteriores das espécies de Tatia são: menor número diploide, presença de sistema de cromossomos sexuais e AgRONs múltiplas em Centromochlus, enquanto espécies de Tatia apresentam AgRON simples e ausência de cromossomos acrocêntricos. Resultados deste estudo mostram que marcadores cromossômicos podem contribuir como evidência para estudos de delimitação taxonômica.(AU)

Chromosomal analysis of Centromochlus heckelii (Siluriformes: Auchenipteridae), with a contribution to Centromochlus definition

Historically, there are divergences in the species allocation between Centromochlus and Tatia. This study aimed to generate the first cytogenetic data about Centromochlus and, by analyzing a population of Centromochlus heckelii from the Amazon River basin, to contribute as evidence to a historical taxonomic dilemma. Diploid number of 46 chromosomes and a heteromorphic pair was found in the female karyotypes, thus characterizing a ZZ/ZW sex chromosome system. Pale blocks of heterochromatin were located in centromeric regions of some chromosomes; however, the exclusive female chromosome (W) is almost entirely heterochromatic. AgNORs were detected in terminal position on the short arms of one acrocentric pair in males and two chromosome pairs in females, the acrocentric plus the sex chromosome pair. Notable differences between Centromochlus heckelii and previous data about species of Tatia are: lower diploid number, presence of a sex chromosome system and multiple AgNORs in Centromochlus, while species of Tatia have simple AgNORs and the absence of acrocentric chromosomes. Results in this study show that chromosomal markers could contribute as evidence to taxonomic delimitation studies.(AU)

Historicamente, há divergências na alocação de espécies entre Centromochlus e Tatia. Este estudo teve como objetivo gerar os primeiros dados citogenéticos para Centromochlus e, através da análise de uma população de Centromochlus heckelii da bacia do rio Amazonas, contribuir como evidência para o dilema histórico taxonômico. Foi encontrado o número diploide de 46 cromossomos e um par heteromórfico nos cariótipos das fêmeas, o que caracteriza um sistema sexual ZZ/ZW. Blocos pálidos de heterocromatina foram localizados na região centromérica de alguns cromossomos; no entanto, o cromossomo exclusivo das fêmeas (W) se apresenta quase todo heterocromático. As AgRONs foram detectadas na posição terminal do braço curto de um par acrocêntrico nos machos e em dois pares cromossômicos nas fêmeas, um par de cromossomos acrocêntricos e o par sexual. Notáveis diferenças entre os dados cromossômicos de Centromochlus heckelii e os dados anteriores das espécies de Tatia são: menor número diploide, presença de sistema de cromossomos sexuais e AgRONs múltiplas em Centromochlus, enquanto espécies de Tatia apresentam AgRON simples e ausência de cromossomos acrocêntricos. Resultados deste estudo mostram que marcadores cromossômicos podem contribuir como evidência para estudos de delimitação taxonômica.(AU)

Genetic characterization of tambaqui stocks from two pisciculture stations in the lower São Francisco River / Caracterização genética de estoques de tambaqui de duas estações de piscicultura no baixo rio São Francisco

Pisciculture has been an important part of the economy in many regions of Brazil, and the tambaqui (Colossoma macropomum) stands out as one of the country's most commercialized native freshwater fish species. Loss of genetic variability can affect characteristics such as reproduction and growth rates, as well as disease resistance and is of great concern in this field. Molecular markers such as mitochondrial DNA genes have been increasingly used to understand genetic variability in species of economic importance. This study aimed to characterize the genetic variability of tambaqui populations reared in two fish farms (Itiúba, AL and Betume, SE) of the lower São Francisco River by analyzing the control region and ATPase genes of mitochondrial DNA. Sequencing of samples from progenies and breeding individuals identified 42 haplotypes (32 unique), of which four haplotypes were shared between the two fish farms as a result of a founder effect, because individuals from Itiúba formed the stock of the Betume fish farming Station. Haplotype diversity was high in both locations. Analysis of Molecular Variance (AMOVA) revealed greater genetic variation within populations (96.76%) than between them (3.24%) and the FST value (0.03) indicated low genetic differentiation between the two populations. The observed high genetic variability can be explained by the number of breeders in the two fish farms (200 in Itiúba and 1400 in Betume) and the breeding management system, which seems to be effective in maintaining stock variability.

A piscicultura tem ocupado um lugar de destaque na economia de muitas regiões do Brasil, e o tambaqui (Colossoma macropomum) se sobressai por ser uma das espécies nativas de peixes de água doce mais comercializadas do país. A diminuição da variabilidade genética pode afetar características como as taxas de reprodução e crescimento, bem como resistência a doenças e é de grande preocupação nesse ramo. Marcadores moleculares, como os genes do DNA mitocondrial, vem sendo cada vez mais utilizados para investigar a variabilidade genética em espécies de importância econômica. Assim, este estudo teve como objetivo caracterizar a variabilidade genética de populações de tambaqui cultivados em duas pisciculturas (Itiúba, AL e Betume, SE) do baixo Rio São Francisco, utilizando a região controle e os genes da ATPase do DNA mitocondrial. O sequenciamento de amostras de progênies e reprodutores identificou 42 haplótipos (32 únicos). Destes, quatro haplótipos foram compartilhados entre as duas pisciculturas estudadas, o que é resultado de um efeito fundador, uma vez que indivíduos de Itiúba foram levados para compor o estoque da Estação de Piscicultura de Betume. A diversidade haplotípica foi alta em ambas as localidades. Análise de Variância Molecular (AMOVA) demonstrou maior variação genética dentro das populações (96.76%) do que entre elas (3.24%) e o valor de Fst (0.03) indicou pouca diferenciação genética entre as duas populações analisadas. A alta variabilidade genética encontrada pode ser explicada pelo número de reprodutores nas duas pisciculturas (200 em Itiúba e 1400 em Betume) e o manejo reprodutivo, que parece ser eficaz na manutenção da variabilidade de estoques.

Genetic characterization of tambaqui stocks from two pisciculture stations in the lower São Francisco River / Caracterização genética de estoques de tambaqui de duas estações de piscicultura no baixo rio São Francisco

Pisciculture has been an important part of the economy in many regions of Brazil, and the tambaqui (Colossoma macropomum) stands out as one of the country's most commercialized native freshwater fish species. Loss of genetic variability can affect characteristics such as reproduction and growth rates, as well as disease resistance and is of great concern in this field. Molecular markers such as mitochondrial DNA genes have been increasingly used to understand genetic variability in species of economic importance. This study aimed to characterize the genetic variability of tambaqui populations reared in two fish farms (Itiúba, AL and Betume, SE) of the lower São Francisco River by analyzing the control region and ATPase genes of mitochondrial DNA. Sequencing of samples from progenies and breeding individuals identified 42 haplotypes (32 unique), of which four haplotypes were shared between the two fish farms as a result of a founder effect, because individuals from Itiúba formed the stock of the Betume fish farming Station. Haplotype diversity was high in both locations. Analysis of Molecular Variance (AMOVA) revealed greater genetic variation within populations (96.76%) than between them (3.24%) and the FST value (0.03) indicated low genetic differentiation between the two populations. The observed high genetic variability can be explained by the number of breeders in the two fish farms (200 in Itiúba and 1400 in Betume) and the breeding management system, which seems to be effective in maintaining stock variability.(AU)

A piscicultura tem ocupado um lugar de destaque na economia de muitas regiões do Brasil, e o tambaqui (Colossoma macropomum) se sobressai por ser uma das espécies nativas de peixes de água doce mais comercializadas do país. A diminuição da variabilidade genética pode afetar características como as taxas de reprodução e crescimento, bem como resistência a doenças e é de grande preocupação nesse ramo. Marcadores moleculares, como os genes do DNA mitocondrial, vem sendo cada vez mais utilizados para investigar a variabilidade genética em espécies de importância econômica. Assim, este estudo teve como objetivo caracterizar a variabilidade genética de populações de tambaqui cultivados em duas pisciculturas (Itiúba, AL e Betume, SE) do baixo Rio São Francisco, utilizando a região controle e os genes da ATPase do DNA mitocondrial. O sequenciamento de amostras de progênies e reprodutores identificou 42 haplótipos (32 únicos). Destes, quatro haplótipos foram compartilhados entre as duas pisciculturas estudadas, o que é resultado de um efeito fundador, uma vez que indivíduos de Itiúba foram levados para compor o estoque da Estação de Piscicultura de Betume. A diversidade haplotípica foi alta em ambas as localidades. Análise de Variância Molecular (AMOVA) demonstrou maior variação genética dentro das populações (96.76%) do que entre elas (3.24%) e o valor de Fst (0.03) indicou pouca diferenciação genética entre as duas populações analisadas. A alta variabilidade genética encontrada pode ser explicada pelo número de reprodutores nas duas pisciculturas (200 em Itiúba e 1400 em Betume) e o manejo reprodutivo, que parece ser eficaz na manutenção da variabilidade de estoques.(AU)