A genome-wide association study for morphometric traits in quarter horse

A genome-wide association study for morphometric traits was conducted in 184 Quarter Horses, 120 from a racing population, and 64 from a cutting population, which were genotyped using the Illumina EquineSNP50 chip. Association analysis was performed with 42,058 single-nucleotide polymorphisms (SNPs) (after quality control) using Qxpak5 software. The following traits were measured: weight (W), rump length (RL), and body length (BL). These morphometric traits are important for the best performance in race and cutting events. For weight, three SNPs associated (P < .0001) were found on chromosomes (Equus caballus autosomes [ECA]) 2 and 3. For rump length, eight SNPs associated (P < .0001) were found on ECA 2, 3, 6, 7, 9, 21, and 26. On ECA 3 and ECA 8, two SNPs were associated (P < .0001) with body length. So, a total of 13 important chromosomal regions were identified with Q values of 0.53 (SNPs for W), 0.40 (SNPs for RL), and 0.99 (SNPs for BL). Positional and functional candidate genes emerging from this study were WWOX and AAVPR1A. Further studies are required to confirm these associations in other populations. (c) 2014 Elsevier Inc. All rights reserved

Evaluation of posture rating curves of a female line of broilers

Objetivou-se com este trabalho estimar os par?metros gen?ticos e fenot?picos dos par?metros da curva de produ??o de ovos, pelo o modelo de polin?mios segmentados (x p- idade das aves ao pico de postura, P- n?vel de produ??o no pico, s - taxa de decr?scimo semanal na produ??o de ovos ap?s o pico e t - tempo entre o in?cio da postura e o pico de produ??o de ovos). Foram utilizados dados da produ??o de ovos semanal da 25? at? 64? semanas de idade, provenientes de 2.398 matrizes de uma linhagem de frangos de corte. A estima??o dos componentes de covari?ncias, herdabilidade e correla??es para esses par?metros da curva de postura foram obtidas por m?xima verossimilhan?a restrita. As tend?ncias gen?ticas foram estimadas com as m?dias dos valores gen?ticos dos par?metros da curva em fun??o do ano de nascimento das matrizes. As m?dias das herdabilidades foram de baixa a m?dia magnitudes, 0,25 (x p), 0,18 (P), 0,17 (s) e 0,10 (t). As correla??es gen?ticas entre o par?metro t e os demais par?metros da curva foram positivas, variando de 0,21 at? 1,00, sendo menor entre t e s e maior entre os par?metros x p e t. Entre os par?metros x p e P, a correla??o tamb?m foi positiva, de magnitude m?dia (0,39). As correla??es foram negativas entre os par?metros s e x p e s e P, apresentando-se menor entre s e x p (-0,17) e maior entre s e P (-0,91). As tend?ncias gen?ticas encontradas para os par?metros indicaram uma redu??o no tempo entre o in?cio e pico de produ??o e idade ao pico de postura. O n?vel de produ??o apresentou uma queda no valor gen?tico ao longo do per?odo avaliado. Pode-se observar poss?vel ganho gen?tico para os par?metros da curva de produ??o de ovos, contudo, deve-se atentar para as correla??es gen?ticas positivas entre os par?metro x p e P, o que pode levar a um aumento do n?vel de produ??o e a um aumento na idade ao pico de produ??o. O mesmo caso acontece com os par?metros x p e s, indicando que as aves mais precoces ao pico poder?o apresentar menor persist?ncia.Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG)Empresa de Pesquisa Agropecu?ria de Minas Gerais (EPAMIG)Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)The objective of this study was to estimate genetic parameters and phenotypic parameters of egg production curve, using the segmented polynomial model(x p- the peak age of the birds in attitude, P - at peak production level, s - rate of decline in weekly egg production after peak, and t - time between the onset of lay and peak egg production). We used data from the weekly egg production from 25 to 64 weeks of age from 2,398 arrays of a lineage of broilers chickens. Estimation of covariance components, heritability and correlations for these parameters curve posture were obtained by restricted maximum likelihood. Genetic trends were estimated with the average breeding values the of parameters of the curve as a function of birth year of the arrays. The mean heritabilities were low to medium magnitude, 0.25 (x p), 0.18 (P), 0.17 (s) e 0.10 (t). Genetic correlations among the parameter t and the other parameters of the curve were positive ranging from 0.21 to 1.00, being lower between t and s, and higher between the parameters x p and t. Between the parameters x p and P the correlation was also positive, of an average magnitude (0.39). Correlations were negative between parameters s and x p, and s and P, presenting itself lower between s and x p (-0.17) and higher between s and P (-0.91). The genetic trends found for the parameters of the model indicated a reduction in time between the production's onset and peak, and age at production's peak. The level of production showed a decline in breeding value over the period evaluated. It can be observed a potential genetic gain for the egg's production parameters' curve; however, it must be paid special attention to the positive genetic correlations between the parameter x p and P. What can lead to an increase in the level of production and may lead to an increase in age at peak production. The same applies to the parameters x p indicating that birds with earlier peaks may present lower persistence

Acurácia da predição genômica para altura do quadril em bovinos Brahman com uso de diferentes matrizes de parentesco

The objective of this work was to evaluate the effects of genomic information on the genetic evaluation of hip height in Brahman cattle using different matrices built from genomic and pedigree data. Hip height measurements from 1,695 animals, genotyped with high-density SNP chip or imputed from 50 K high-density SNP chip, were used. The numerator relationship matrix (NRM) was compared with the H matrix, which incorporated the NRM and genomic relationship (G) matrix simultaneously. The genotypes were used to estimate three versions of G: observed allele frequency (HGOF), average minor allele frequency (HGMF), and frequency of 0.5 for all markers (HG50). For matrix comparisons, animal data were either used in full or divided into calibration (80% older animals) and validation (20% younger animals) datasets. The accuracy values for the NRM, HGOF, and HG50 were 0.776, 0.813, and 0.594, respectively. The NRM and HGOF showed similar minor variances for diagonal and off-diagonal elements, as well as for estimated breeding values. The use of genomic information resulted in relationship estimates similar to those obtained based on pedigree; however, HGOF is the best option for estimating the genomic relationship matrix and results in a higher prediction accuracy. The ranking of the top 20% animals was very similar for all matrices, but the ranking within them varies depending on the method used.O objetivo deste trabalho foi avaliar os efeitos da informação genômica na avaliação genética para altura do quadril em bovinos da raça Brahman, por meio de diferentes matrizes construídas com dados genômicos e de pedigree. Utilizaram-se medidas de altura do quadril de 1.695 animais, genotipados com SNP chip de alta densidade ou imputados do 50 K SNP chip de alta densidade. A matriz de pedigree “numerator relationship matrix” (NRM) foi comparada à matriz H, a qual incorporou as matrizes NRM e de parentesco genômico (G) simultaneamente. Os genótipos foram utilizados para estimar três versões de G: frequência observada dos alelos (HGOF), média da menor frequência alélica (HGMF) e frequência de 0,5 para todos os marcadores (HG50). Para a comparação das matrizes, foram utilizadas informações completas ou divididas em conjuntos de dados de calibração (80% dos animais mais velhos) e de validação (20% dos mais jovens). Os valores de acurácia para NRM, HGOF e HG50 foram 0,776, 0,813 e 0,594, respectivamente. NRM e HGOF foram semelhantes, com menores variâncias para os elementos da diagonal e fora da diagonal, bem como para os valores genéticos estimados. O uso de informações genômicas resultou em estimativas de parentesco semelhantes às obtidas com base em pedigree; entretanto, H­GOF é a melhor opção para estimar a matriz de parentesco genômico e resulta em maiores acurácias de predição. O ranking dos animais top 20% foi muito semelhante para as matrizes, mas a classificação dentro destas varia dependendo do método

Estimativas de parâmetros genéticos para características morfométricas em cavalos Quarto de Milha de Corrida

With highlighted sprint ability, the racing line is important segment within the Quarter Horses breed, with huge impact on agribusiness. Theseanimals have noted morphological differences when compared to other lines within the breed, especially for larger body size proportions.The objective of this study was to estimate genetic parameters forbody measurements traitsof the racing line of the Quarter Horses breed via Bayesian inference. Here,289 animals of both sexes, registered at brazilian association of breeders (ABQM), were used. The results showed high coefficient of heritability for body length (0.74) and back-loin lenght(0.61). The heritability coefficients for height at withersand croup length were moderate (0.44 and 0.47, respectively). High genetic correlation for body length and croup length and for body length and back-loins lengthwas also observed(0.80 and 0.76, respectively). Taking into account the estimates of heritability and genetic correlations between body measurement traits, the body length and height at withers traits proved to be appropriate to provide future researches that investigate the genetic correlation between body measurements and racing performance

Marked assisted selection for horses racing performance

Although equines have participated in the forming and development of several civilizations around the world since their domestication 6,000 years ago in comparison to other species that have zootechnical interest, few researches have been done related to animal breeding area, especially in Brazil. Some reasons for that are difficulties associated with the species as well as operational aspects. However, developments in genetics in the last decades contributed to a better understanding of the traits related to reproduction, heath, behavior and performance of domestic animals, including equines. Recent technologies as next generation sequencing methods and the high density chips of SNPs for genotyping allowed some advances in the researches already done. These researches used basically the candidate gene strategy, and identified genomic regions related to diseases and syndromes and, more recently, the performance in sport competition and specific abilities. Using these genomic analysis tools, some regions related to race performance have been identified and based on this information; genetic tests to select superior animals for racing performance have started to be available in the market.</p

Seleção assistida por marcadores para o melhoramento do desempenho de equinos em corridas

Although equines have participated in the forming and development of several civilizations around the world since their domestication 6,000 years ago in comparison to other species that have zootechnical interest, few researches have been done related to animal breeding area, especially in Brazil. Some reasons for that are difficulties associated with the species as well as operational aspects. However, developments in genetics in the last decades contributed to a better understanding of the traits related to reproduction, heath, behavior and performance of domestic animals, including equines. Recent technologies as next generation sequencing methods and the high density chips of SNPs for genotyping allowed some advances in the researches already done. These researches used basically the candidate gene strategy, and identified genomic regions related to diseases and syndromes and, more recently, the performance in sport competition and specific abilities. Using these genomic analysis tools, some regions related to race performance have been identified and based on this information; genetic tests to select superior animals for racing performance have started to be available in the market.Embora os equinos tenham participado da formação e do desenvolvimento de várias civilizações no mundo todo desde sua domesticação há 6.000 anos, em relação a outras espécies de interesse zootécnico, poucas pesquisas vêm sendo realizadas na área de melhoramento genético, especialmente no Brasil. Dificuldades inerentes à espécie e em função de aspectos operacionais têm sido alguns dos contratempos. No entanto, avanços na genética ao longo das últimas décadas contribuíram para o melhor entendimento de características relacionadas à reprodução, à saúde, ao comportamento e ao desempenho dos animais domésticos, incluindo os equinos. Tecnologias recentes como os métodos de sequenciamento de última geração e os chips de genotipagem de SNPs de alta densidade permitiram progresso nas pesquisas até então realizadas, as quais se utilizavam basicamente da estratégia do gene candidato, proporcionando a identificação de regiões genômicas relacionadas à patias e síndromes e, mais recentemente, a desempenho em provas esportivas e aptidões específicas. Pela utilização dessas ferramentas de análise do genoma, regiões relacionadas ao desempenho em corridas vêm sendo identificadas, e a partir dessas informações, testes genéticos para a seleção de indivíduos superiores para desempenho em corridas começam a ser disponibilizados no mercado

Accuracy of genomic selection predictions for hip height in Brahman cattle using different relationship matrices

The objective of this work was to evaluate the effects of genomic information on the genetic evaluation of hip height in Brahman cattle using different matrices built from genomic and pedigree data. Hip height measurements from 1,695 animals, genotyped with high-density SNP chip or imputed from 50 K high-density SNP chip, were used. The numerator relationship matrix (NRM) was compared with the H matrix, which incorporated the NRM and genomic relationship (G) matrix simultaneously. The genotypes were used to estimate three versions of G: observed allele frequency (H-GOF), average minor allele frequency (H-GMF), and frequency of 0.5 for all markers (H-G50). For matrix comparisons, animal data were either used in full or divided into calibration (80% older animals) and validation (20% younger animals) datasets. The accuracy values for the NRM, H-GOF, and H-G50 were 0.776, 0.813, and 0.594, respectively. The NRM and H-GOF showed similar minor variances for diagonal and off-diagonal elements, as well as for estimated breeding values. The use of genomic information resulted in relationship estimates similar to those obtained based on pedigree; however, H-GOF is the best option for estimating the genomic relationship matrix and results in a higher prediction accuracy. The ranking of the top 20% animals was very similar for all matrices, but the ranking within them varies depending on the method used

Morphological traits and type of dairy goats registered in Brazil from 1976 to 2009

Data from 2439 goats of the Saanen, Alpine, Anglo Nubian and Toggenburg breeds recorded from 1976 to 2009 by the Association of Goats and Sheep Breeders of Minas Gerais were used in principal component analysis. After consistency of data, six morphological variables (thorax perimeter, body length, withers height, height, width and length of the rump) and 12 variables related to breed standard score and fitness (breed characteristic, head, palette and topline, feet and legs, dairy type, body capacity, udder, rear and front ligament, udder texture, teat and final score) were analyzed. Based on the magnitude of the eigenvalue (lower than 0.7), eleven variables considered redundant were discarded, resulting in reduced costs of technician labor to evaluate the animals. Maintenance of records on height, length, rump width, breed characteristic, dairy type, front ligament and udder texture is recommended