The objective of this study was to perform a genome-wide association study (GWAS) to detect chromosome regions associated with indicator traits of sexual precocity in Nellore cattle. Data from ...Nellore animals belonging to farms which participate in the DeltaGen® and Paint® animal breeding programs, were used. The traits used in this study were the occurrence of early pregnancy (EP) and scrotal circumference (SC). Data from 72,675 females and 83,911 males with phenotypes were used; of these, 1,770 females and 1,680 males were genotyped. The SNP effects were estimated with a single-step procedure (WssGBLUP) and the observed phenotypes were used as dependent variables. All animals with available genotypes and phenotypes, in addition to those with only phenotypic information, were used. A single-trait animal model was applied to predict breeding values and the solutions of SNP effects were obtained from these breeding values. The results of GWAS are reported as the proportion of variance explained by windows with 150 adjacent SNPs. The 10 windows that explained the highest proportion of variance were identified. The results of this study indicate the polygenic nature of EP and SC, demonstrating that the indicator traits of sexual precocity studied here are probably controlled by many genes, including some of moderate effect. The 10 windows with large effects obtained for EP are located on chromosomes 5, 6, 7, 14, 18, 21 and 27, and together explained 7.91% of the total genetic variance. For SC, these windows are located on chromosomes 4, 8, 11, 13, 14, 19, 22 and 23, explaining 6.78% of total variance. GWAS permitted to identify chromosome regions associated with EP and SC. The identification of these regions contributes to a better understanding and evaluation of these traits, and permits to indicate candidate genes for future investigation of causal mutations.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In beef cattle breeding programs, various selection criteria have been proposed and employed with the aim of improving traits related to carcass composition and the quality of the final product, ...meat. However, the importance of genotype by environment interaction (G×E) for such traits is still not well understood. Our objectives were: 1) to investigate the importance of G×E on ultrasound carcass traits, growth and visual scores and 2) to estimate the genetic correlation of ultrasound carcass traits with growth and visual scores taking into account the G×E in Hereford and Braford cattle. A multiple-trait reaction norm model was fitted to the field records of 37,948 animals. With the exception of postweaning average daily weight gain (ADG), the G×E can lead to important changes in the ranking of estimated breeding values of sires across environments for all traits. Thus, models that consider heterogeneity of genetic variances along an environmental gradient may be considered more appropriate for genetic evaluations of animals reared under conditions similar to the present study. Based on estimates of genetic correlation, the quality of visual scores or ADG as indicators of carcass quality assessed by ultrasonography is dependent on the production environment.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Stayability (STAY) is a way to evaluate the productive longevity of females. Measuring the STAY at each cow calving allows earlier indicators of longevity to be obtained. Our objective with this ...study was to verify the association between STAY and consecutive calvings and traits potentially used as selection criteria in beef cattle, such as age at first calving (AFC), days to calving (DC), weaning weight (WW), and yearling weight (YW). Data from the Nelore, Angus/Brangus, and Hereford/Braford breeds were used. The estimation of variance components and subsequent prediction of breeding values were performed for all traits. The estimated breeding values (EBV) were used to analyse the association between STAY and the other traits. The Pearson's correlation estimated between the EBV for the intercept coefficient for STAY to consecutive calvings and those of AFC, DC, WW (direct and maternal effects), and YW was favourable and of low magnitude (<0.25) depending on the breed studied. The influence of the genetic merit of AFC on the chance of selection for STAY was favourable and relevant regardless of the intensity of selection and breed. DC and WW (maternal effect) traits were favourably influenced by the chance of selection for STAY, irrespective of breed. The WW (direct effect) did not affect the chance of selection for STAY for the Nelore and Hereford/Braford breeds and negatively influenced, but to a small extent, the Angus/Brangus breed. For YW, an increase in genetic merit affected the chances of selection for STAY, depending on the breed and selection intensity evaluated. The influence of the genetic merit for AFC, DC, and WW (maternal effect) on the chance of selection for STAY to consecutive calvings was favourable and relevant regardless of the selection intensity scenario evaluated. The WW (direct effect) did not influence the chance of selection for STAY. For the scenario with high selection intensity, the selection for YW favourably influenced the chance of selection for STAY in Angus/Brangus and Hereford/Braford breeds but not in Nelore.
The objective of the present work was to develop species-specific microsatellite markers for
P. scalare
and to analyze the diversity and genetic structure of a wild population, from the Amazon River, ...and three commercial stocks (common, marble, and clown morphological variants), from farmers in Vieras-Minas Gerais. Through microsatellite-enriched genetic libraries, 11 microsatellite markers with adequate amplification patterns were characterized. Population genetic analysis identified eight polymorphic
loci
that generated 66 alleles ranging from two alleles (PSCA1B3) to nine (PSCA2H1). The polymorphic information content ranged from 0.031 to 0.827. High genetic differentiation was observed between the wild population and the stocks, and moderate differentiation between the three stocks. Deviation in the Hardy-Weinberg equilibrium was observed in one
locus
in the wild population, in five
loci
in the common morphological variant, in two in the marble, and in two in the clown morphological variant. Bayesian analysis of genetic structure revealed the existence of two clusters, one represented by the natural population and the other by the stocks. The developed microsatellite markers serve as a tool for the analysis of diversity and genetic structure and conservation studies of
P. scalare
.
Jewel tetra (Hyphessobrycon eques) is a freshwater fish found in several rivers and basins in South America. The present study is the first study to create a panel of microsatellite markers for ...detecting genetic diversity in H. eques and evaluating the application of these markers in Serrapinnus notomelas. In total, 44 individuals were genotyped from the natural (WIL, n = 20) and stock in captivity (CAP, n = 24) population. Moreover, 19 microsatellite markers were obtained, of which only 8 loci presented a high degree polymorphism. In total, 45 alleles were detected, ranging from 126 bp (Hype2G2) to 420 bp (Hype2E2). The Hardy-Weinberg equilibrium (p < 0.05) revealed significant difference in one locus in WIL (Hype1G4) and three loci in CAP (Hype1F4, Hype2C3, and Hype2G2). Null alleles (p < 0.05) were present in only one locus (Hype1G4). The WIL and CAP populations revealed high genetic diversity during F
ST
analysis. The cross-amplification test for S. notomelas revealed that only two loci (Hype2C3 and Hype2G2B) presented satisfactory transferability results. The developed microsatellite primers will be useful in studying the genetic diversity and population structure of H. eques in wild populations and fish farms in the Brazilian and other South American basins.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The formation of fish breeding stocks for fish farming or conservation programs is commonly carried out from the capture of fish in natural environments. Information on the geographic and genetic ...origin of these stocks is important to guide actions that allow correct management in captivity and, when lost, harm production and genetic conservation. In this sense, the objective of this study was to evaluate the genetic diversity and origin of two breeding stocks of matrinxã, Brycon amazonicus (INPA, Amazonas - INPA and Nova Motum, Mato Grosso - NM). A total of 68 caudal fin samples were collected, including 33 INPA samples and 35 NM samples. Twenty pairs of microsatellite primers were tested, but only seven primers showed satisfactory amplification, amplifying 41 alleles ranging from 187-318 bp. The polymorphic information content ranged from 0.135 (Borg25) to 0.782 (Bh6). Exclusive alleles were observed for both populations (INPA: 04 and NM: 18). Allelic richness results revealed that there was increased loss of genetic variation in NM, indicating a lower evolutionary potential of this stock. The average values of the observed heterozygosity corroborated this statement; however, there were high values for INPA (0.545) and NM (0.475), signifying an adequate genetic variability. An imbalance was found in the Hardy-Weinberg equilibrium at the Borg59 locus in INPA (P < 0.05), possibly due to the effect of null alleles, but was attributed to a founder effect. For NM, an imbalance in the Hardy-Weinberg equilibrium was observed at loci BoM13 and Bh6, which together with the results of the mean inbreeding coefficient values demonstrated the presence of genetic drift. The analysis of molecular variance showed greater variation within populations than between them, and was confirmed by the genetic differentiation value (0.086 - moderate genetic differentiation) and by the distance and genetic identity values (0.273 and 0.761, respectively). Bayesian analysis designated a value of K = 2, with the presence of structuring for NM and INPA; however, with correlated allelic frequencies, confirming a common origin. This origin was corroborated by the presence of gene flow through the number of migrants (5.691). Based on these results, there was a moderate genetic variability for INPA and NM and their common origin was confirmed. Recommendations are also included to minimize the probability of inbreeding processes or genetic drift in the studied stocks.
The German Shepherd dog breed is the most popular breed globally and in Brazil. The study of the population structure through pedigree information is an essential tool to understand the history of ...the Brazilian German Shepherd dog breed. This study evaluated the status of genetic diversity and population structure of the Brazilian German Shepherd dog breed. The pedigree included a total of 77,938 animals born between 1970 and 2014. The average generation interval in this population was 3.91 years. Considering the reference population, 2,183 founders were identified. Approximately 3% of the genetic diversity of the current population (2010-2014) was lost, most of which was due to genetic drift. The effective population size was relatively small, and the pedigree showed bottlenecks indicating a loss of genetic diversity in this breed. These results indicated the need to adopt measures against the excessive increase in inbreeding and monitor effective population size to minimize genetic diversity loss. Key words: conservation, inbreeding, pedigree analysis, population structure. A raca Pastor Alemao e uma das racas mais populares no mundo e no Brasil. O estudo da estrutura populacional por meio de informacoes de pedigree e uma ferramenta essencial para o entendimento da historia dessa raca no Brasil. Objetivou-se com o estudo avaliar o status da diversidade genetica e da estrutura populacional de caes da raca Pastor Alemao. O pedigree incluiu um total de 77.938 animais nascidos entre 1970 e 2014. O intervalo medio de geracao nesta populacao foi de 3,91 anos. Considerando a populacao de referencia, foram identificados 2.183 fundadores. Cerca de 3% da diversidade genetica da populacao atual (2010-2014) foi perdida, a maior parte devido a deriva genetica. O tamanho efetivo da populacao foi relativamente pequeno e o pedigree apresentou gargalos indicando uma perda de diversidade genetica nesta raca. Esses resultados indicam a necessidade de adocao de medidas contra o aumento excessivo da endogamia e do monitoramento do tamanho efetivo da populacao para minimizar a perda de diversidade genetica. Palavras-chave: analise de pedigree, conservacao, endogamia, estrutura da populacao.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The German Shepherd dog breed is the most popular breed globally and in Brazil. The study of the population structure through pedigree information is an essential tool to understand the history of ...the Brazilian German Shepherd dog breed. This study evaluated the status of genetic diversity and population structure of the Brazilian German Shepherd dog breed. The pedigree included a total of 77,938 animals born between 1970 and 2014. The average generation interval in this population was 3.91 years. Considering the reference population, 2,183 founders were identified. Approximately 3% of the genetic diversity of the current population (2010-2014) was lost, most of which was due to genetic drift. The effective population size was relatively small, and the pedigree showed bottlenecks indicating a loss of genetic diversity in this breed. These results indicated the need to adopt measures against the excessive increase in inbreeding and monitor effective population size to minimize genetic diversity loss.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Resumo: O objetivo deste trabalho foi estimar o efeito da endogamia sobre a produção de leite e sua persistência durante a lactação, em bovinos Gir leiteiro, bem como determinar o impacto de se ...considerar ou não o efeito da endogamia na avaliação genética dessa característica. Utilizaram-se 89.490 registros de produção no dia do controle, de 11.675 vacas em primeira lactação. O coeficiente e o incremento de endogamia individuais e o número equivalente de gerações completas de cada indivíduo foram computados. A depressão por endogamia foi estimada pela inclusão do efeito do incremento individual de endogamia, em um modelo de regressão aleatória. As soluções para a depressão por endogamia, de acordo com a classe de incremento individual de endogamia e a quinzena da lactação, variaram entre -1,238 e -0,135 kg, o que indica a redução da produção de leite com o aumento da endogamia. Em níveis mais elevados, a endogamia reduziu a persistência da produção de leite. A inclusão do efeito da endogamia no modelo de avaliação genética não afetou as estimativas de parâmetros genéticos e, praticamente, não alterou a predição dos valores genéticos e a classificação dos animais. Pode-se incluir o efeito da endogamia no modelo estatístico para a avaliação genética da característica produção de leite.
Transferability of heterologous microsatellite primers in Leiarius marmoratus Pandolfi, Victor César Freitas; Yamachita, Andrei Lincoln; Souza, Felipe Pinheiro de ...
Semina. Ciências agrárias : revista cultural e científica da Universidade Estadual de Londrina,
01/2020, Letnik:
41, Številka:
5supl1
Journal Article
Recenzirano
Odprti dostop
The Amazonian Jundiá (Leiarius marmoratus) (Siluliformes: Pimelodidae) is a species of catfish with social and economic importance in some South American countries such as Brazil and Colombia. ...Genetic evaluation of this species is limited due to the lack of specific molecular markers, hindering studies on genetic diversity and structure in animals under captive conditions or in natural populations. The objective of the present study was to evaluate the transferability of heterologous microsatellite markers in Leiarius marmoratus. Thirty-two heterologous primers were tested in L. marmoratus. The primers that presented the best standards were applied to 20 specimens, and the number of alleles (Na), number of effective alleles (Ne), gene diversity per Locus (GdL) and percentage of amplification failure (Md) were calculated. Eleven primers demonstrated satisfactory transferability patterns, all from the fish of the Pimelodidae family, of which, seven were monomorphic and four polymorphic. The eleven markers presented low percentage of Md (mean was 5.9% samples per locus). Na varied from one to two alleles per locus, revealing low polymorphism in the evaluated samples. The mean Ne and GdL numbers were 1.77 and 0.32, respectively. The transferability of the heterologous microsatellite loci in L. marmoratus was shown to be possible. However, further tests are needed to apply these markers in population genetic studies.
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