Models which might explain negative correlations between direct and maternal genetic effects

Robinson, D. L.

doi:10.1016/0301-6226(96)00002-4

Cited by 147 publications

(129 citation statements)

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“…Embora em vários trabalhos tenham sido relatadas correlações genéticas negativas entre os efeitos genéticos direto e materno, neste estudo, optou-se por fixar esta correlação em zero, uma vez que pesquisas têm apontado que a correlação negativa pode ser devida a problemas de estrutura dos dados e/ou efeitos não considerados no modelo (Robinson, 1996;Meyer, 1997).…”

Section: Resultsunclassified

Estimativas de parâmetros genéticos para os escores visuais e suas associações com peso corporal em bovinos de corte

et al. 2010

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RESUMO -Foram avaliados 27.523 e 21.746 registros das características conformação, precocidade e musculatura à desmana e ao sobreano, respectivamente, para estimar os componentes de covariância entre estas características e entre estas e os pesos corporais medidos nas mesmas idades. Para as análises dos dados, foram empregados modelos animais com efeitos genéticos direto e materno e efeito de ambiente permanente materno. Máxima verossimilhança restrita foi empregada para estimar os parâmetros genéticos. As estimativas de herdabilidade dos escores à desmama foram 0,13; 0,25 e 0,23 para conformação, precocidade e musculatura, respectivamente. As estimativas de herdabilidade dos escores visuais avaliados ao sobreano foram de maiores magnitudes (0,24; 0,32 e 0,27 para conformação, precocidade e musculatura, respectivamente).As estimativas das correlações genéticas entre escores medidos às mesmas idades, considerando desmana e sobreano, foram 0,67 e 0,75 entre conformação e precocidade; 0,61 e 0,71 entre conformação e musculatura; 0,95 e 0,95 entre precocidade e musculatura. As correlações genéticas estimadas entre o peso corporal à desmama e conformação, precocidade e musculatura, respectivamente, foram 0,97; 0,67 e 0, 62. As estimativas entre conformação, precocidade, musculatura ao sobreano e o peso corporal foram 0,83; 0,59 e 0,58, respectivamente. Os resultados indicam que os escores visuais podem ser utilizados como critérios de seleção. Aumento nos pesos corporais deve ser esperado como resposta correlacionada à seleção para essas características.Palavras-chave: avaliação visual, correlação genética, gado de corte, herdabilidade, Nelore, peso Genetic parameters estimates for visual scores and their association with body weight in beef cattleABSTRACT -It was evaluated 27,523 and 21,746 records on traits of conformation, finishing precocity and musculature measured at weaning and a year after weaning, respectively, for the estimation of (co)variance components among these traits, and between them and body weights at the same ages. The data were analyzed by employing an animal model with direct and maternal genetic effect and permanent maternal environment effect. Restricted maximum likelihood was employed for the estimation of genetic parameters. The heritability estimates of visual scores at weaning were 0.13, 0.25, 0.23 for conformation, finishing precocity, and musculature respectively. The heritability estimates of visual scores one year after weaning were greater: 0.24, 0.32 and 0.27 for conformation, finishing precocity, and musculature, respectively. The genetic correlations estimates among scores at the same ages were: 0.67 and 0.75 between conformation and finishing precocity; 0.61 and 0.71 between conformation and musculature; 0.95 and 0.95 between finishing precocity and musculature, considering weaning and one year further, respectively. The genetic correlations estimated between weaning weight and conformation, finishing precocity, and musculature, were 0.97, 0.67 and 0.62, respectively. The estimat...

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Section: Resultsunclassified

Estimativas de parâmetros genéticos para os escores visuais e suas associações com peso corporal em bovinos de corte

et al. 2010

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“…Mean estimates in the literature, as reported in reviews by Meyer (1992), Mohiuddin (1993), and Koots et al (1994b), are solidly negative. Negative correlations between direct and maternal effects may be due not only to genetic antagonism but also to negative environmental dam-offspring covariances (Baker 1980), sire-by-year variation that is unaccounted for (Robinson 1994), or selective reporting of data (Mallinckrodt et al 1995). Such sources of error are more probable in field data than controlled experiments like this study.…”

Section: Maternal Componentsmentioning

confidence: 86%

Estimates of direct and maternal genetic parameters for weight traits and backfat thickness in a multibreed population of beef cattle

Tosh

Kemp²,

Ward³

1999

Can. J. Anim. Sci.

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. 1999. Estimates of direct and maternal genetic parameters for weight traits and backfat thickness in a multibreed population of beef cattle. Can. J. Anim. Sci. 79: 433-439. Variance components were estimated for weight at birth, weaning, and 365 d of age, and yearling ultrasonic backfat thickness in a multibreed population of beef cattle. Data (n = 5880) were available on F 1 animals and various crosses leading up to, and including, a composite breed (7/16 British, 1/4 Charolais, 1/4 Simmental, and 1/16 Limousin). Single-and two-trait analyses were conducted using an animal model and derivative-free REML procedures. Covariates representing fractional contributions of each of the four purebred groups and average heterotic effects, both direct and maternal, accounted for breed composition. Direct and maternal genetic, maternal permanent environmental, and residual effects were the random variables. Only minor differences existed between parameter estimates obtained from the various analyses. Mean direct heritabilities were 0.51, 0.33, 0.48, and 0.37 for weight at birth, weaning, and 365-d, and backfat, respectively, which, though well within the range of published estimates, seemed higher than average, indicating diversity in the founding purebreds. Mean maternal heritabilites were 0.09, 0.13, and 0.08 for the three consecutive weights. A likelihood ratio test showed maternal heritability and(or) the direct-maternal correlation was important (P < 0.001) for 365-d weight. Averaged across weights, the direct-maternal correlation was 0.07, lacking evidence of genetic antagonism. No age of dam or random maternal effects on backfat were apparent. Phenotypic correlations between weight at birth and weaning and weight at weaning and 365-d were 0.46 and 0.76, respectively. Though moderate between birth and weaning weight, maternal genetic and permanent environmental correlations between weaning and 365-d weight approached unity, demonstrating maternal carryover effects. Phenotypic and genetic correlations of 0.19 and -0.13, respectively, implied a limited association between 365-d weight and backfat, which possibly would have been stronger had fat been measured later in life. Estimates of variance components suitable for general use can be obtained from data from multibreed animals by considering breed and heterotic effects. Des covariants représentant les contributions proportionnelles de chacun des quatre groupes de race et les effets hétérotiques moyens, tant directs que maternels, prenaient en compte la composition génétique des animaux. Les effets génétiques directs et maternels, les effets environnementaux permanents maternels et les effets résiduels constituaient les variables aléatoires. Seules des différences minimes apparaissaient entre les valeurs paramétrales obtenues des diverses analyses. Les coefficients d'héritabilité directe moyens étaient, respectivement, de 0,51, 0,33, 0,48 et 0,37 pour le poids à la naissance, au sevrage et à 365 jours et pour l'épaisseur du gras de couverture. Ces chiffres, bien que...

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“…Obtaining accurate estimates of the correlation between direct and maternal genetic effects has proven to be difficult and data and model dependent. Robinson (1996) showed, using simulated data, that negative estimates of correlation between direct and maternal genetic effects may be obtained in the absence of a true antagonism between them.…”

Section: Discussionmentioning

confidence: 98%

Analyses of lamb survival of Scottish Blackface sheep

Conington

Brotherstone

et al. 2007

Animal

126

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Scottish Blackface lamb viability records at birth, and postnatal survival from 1 day to 14 days, from 15 days to 120 days and from 121 days to 180 days were used to determine influential factors and to estimate variance components of lamb survival traits. The binary trait viability at birth was analysed using a linear model whereas the postnatal survival traits were analysed as continuous traits using a Weibull model. The data consisted of about 15 000 survival records of lambs born from 1996 to 2005 on two farms in Scotland. The models included fixed factors that had significant effects and random direct and maternal additive genetic effects and maternal litter effects for viability at birth, and sire and maternal litter effects for the postnatal survival traits. The possible effect of maternal behaviour measured around lambing on lamb survival was investigated in separate analyses. Male lambs were found to be at a higher risk of mortality than females during all periods considered. The effect of type of birth and age of dam was more important during the preweaning period than at later ages. The postnatal hazard rate was not significantly affected by the behaviour score of the dams. The genetic merit of dams had more influence on viability at birth than the genetic merit of lambs themselves. Estimates of heritability for postnatal survival traits were in the range of 0.18 to 0.33 and were significantly greater than zero. These results indicate that lamb survival can be improved through farm management practices and genetic selection. Both animal and maternal genetic effects should be considered in breeding programmes for improving viability at birth.

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Models which might explain negative correlations between direct and maternal genetic effects

Cited by 147 publications

References 8 publications

Estimativas de parâmetros genéticos para os escores visuais e suas associações com peso corporal em bovinos de corte

Estimativas de parâmetros genéticos para os escores visuais e suas associações com peso corporal em bovinos de corte

Estimates of direct and maternal genetic parameters for weight traits and backfat thickness in a multibreed population of beef cattle

Analyses of lamb survival of Scottish Blackface sheep

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