Genetic parameters of growth in rainbow trout, Salmo gairdneri, prior to maturation

1986 ◽  
Vol 28 (2) ◽  
pp. 306-312 ◽  
Author(s):  
L. R. McKay ◽  
P. E. Ihssen ◽  
G. W. Friars
Keyword(s):  
Rainbow Trout ◽  
Maternal Effects ◽  
Environmental Effects ◽  
Condition Factor ◽  
Relative Magnitude ◽  
Genetic Effects ◽  
Salmo Gairdneri ◽  
Family Selection ◽  
Egg Weight ◽  
Heritability Estimates

The relative magnitude of additive genetic effects, nonadditive genetic effects, maternal effects, and common environmental effects was determined for size, growth, and condition factor in rainbow trout of various ages, from the egg to the yearling stage, using a factorial mating system. Heritability estimates for length and weight ranged from 0.09 to 0.32, except for dried egg weight, where no additive genetic variation was detected. Condition factors were more heritable than size, with heritability estimates ranging from 0.24 to 0.46. Maternal effects were only important for dried egg weight and early fry size, and decreased rapidly with age as heritability increased. Egg weight, fry size, and fry condition factors were influenced by common environmental effects and (or) nonadditive genetic effects, but confounding of these sources of variation prevented exact estimation of their relative magnitude. Nonadditive genetic effects were completely absent for yearling size but were present for yearling condition factors. Individual or between-family selection on size should produce some response unless selection is done on very young fry or families are housed separately. For very young fry or where families are not replicated across tanks, within-family selection will be necessary to identify genetically superior fish, because of strong maternal or common environmental effects. Genetic correlations between size or condition factors measured at different ages were all positive, so selection at one stage should improve size or condition factor at another.Key words: rainbow trout, growth, heritability, maternal effects, genetics.

scholarly journals Determination of the best model for estimating heritability of economic traits and their genetic and phenotypic trends in Iranian native fowl

2013 ◽  
Vol 56 (1) ◽  
pp. 237-245
Author(s):  
M. Salehinasab ◽  
S. Zerehdaran ◽  
M. A. Abbasi ◽  
S. Alijani ◽  
S. Hassani
Keyword(s):  
Maternal Effects ◽  
Environmental Effects ◽  
Sexual Maturity ◽  
Information Criterion ◽  
Genetic Effects ◽  
Likelihood Method ◽  
Economic Traits ◽  
Egg Weight ◽  
Basic Model ◽  
Egg Number

Abstract. The objective of the present study was to estimate the heritability and to assess the existence of maternal effects for economic traits in Iranian native fowl. Variance components were estimated for body weight at hatch (BW0), 8 (BW8) and 12 (BW12) weeks of age, age at sexual maturity and weight at sexual maturity, egg number and average egg weight at 28th, 30th and 32nd weeks using restricted maximum likelihood method and six animal models. The best model was determined using the Akaike information criterion for each trait. For age at sexual maturity, the basic model consisting of direct genetic effects was superior. For weight at sexual maturity and egg number, a model consisting of maternal permanent environmental effects in addition to direct genetic effects was the best. For average egg weight at 28th, 30th and 32nd weeks, the model with direct and maternal genetic effects assuming no covariance between them was the best. For BW0, BW8 and BW12, the model including maternal genetic and permanent environmental effects in addition to direct genetic effects was the most appropriate. The estimates of direct heritability ranged from 0.05 (BW0) to 0.35 (weight at sexual maturity). Direct genetic variance and heritability were overestimated if maternal effects were ignored in the statistical model for all traits except ASM. The results indicated that the evaluation of direct and maternal genetic and phenotypic trends based on the best model for each trait was carried out. Maternal genetic trends for BW0, BW8, BW12 and average egg weight at 28th, 30th and 32nd weeks were significantly positive. Present results indicated favourable effects of the performed breeding program for all traits except BW0, during generations.

A Genetic Analysis of Taste Threshold for Phenylthiocarbamide

1981 ◽  
Vol 30 (1) ◽  
pp. 51-57 ◽  
Author(s):  
C. C. Morton ◽  
R. M. Cantor ◽  
L. A. Corey ◽  
W. E. Nance
Keyword(s):  
Genetic Analysis ◽  
Maternal Effects ◽  
Environmental Effects ◽  
Environmental Parameters ◽  
Genetic Effects ◽  
Broad Sense Heritability ◽  
Taste Threshold ◽  
Confidence Levels ◽  
Jackknife Procedure ◽  
Additive Genetic Effects

Taste threshold for phenylthiocarbamide (PTC) was measured in 393 offspring from the families of 85 monozygotic (MZ) twin pairs. PTC scores were bimodally distributed with modes at one and eight and the antimode at five. Because of the non-normality of the distribution, a jackknife procedure was used to obtain 95% confidence intervals for the estimates of genetic, maternal, and environmental parameters. Analyses which assumed no epistasis and which included additive genetic effects revealed that 37.9% of the observed variation in PTC threshold was due to additive genetic effects, 16.6% was due to dominance effects, 14.2% was due to maternal effects, 13.7% was due to a common sibship environment, and 17.6% was due to random environmental effects, yielding a broad sense heritability of 0.55 for the threshold ability to taste PTC. Analyses which did not include additive genetic effects revealed 26.6% of the observed variance was due to dominance effects, 23.6% to maternal effects, and 49.8% to environmental effects at the 0.67 confidence levels, but that environmental factors accounted for 72.4% and dominance effects for 23.6% of the observed variation at the 95% level.

Estimates of genetic parameters for growth and skeletal measurements in Thai swamp buffalo

2000 ◽  
Vol 70 (3) ◽  
pp. 399-406
Author(s):  
K. Meyer ◽  
H. -U. Graser ◽  
A. Na-Chiangmai
Keyword(s):  
Total Variation ◽  
Genetic Association ◽  
Maternal Effects ◽  
Genetic Parameters ◽  
Genetic Effects ◽  
Environmental Correlations ◽  
Length Measurements ◽  
Swamp Buffalo ◽  
Heritability Estimates ◽  
Additive Genetic Effects

AbstractEstimates of genetic parameters were obtained for weight, hip height, heart girth and shoulder to pin length measurements on Thai swamp buffalo, recorded at birth and weaning. Direct heritability estimates were 0·26 for weights at both ages and were low for skeletal measurements, ranging from 0·11 to 0·19. Low values could, in part at least, be caused by inaccuracies in recording. All traits were subject to maternal effects, permanent environmental maternal effects on traits recorded at weaning explaining proportionately up to 0·14 of the total variation. Estimates of genetic (direct and maternal) and permanent environmental correlations between traits recorded at the same time were high throughout, ranging from 0·83 to 0·97 for additive genetic effects and being close to unity otherwise. Except for heart girth measured at weaning, there appeared to be comparatively little genetic association between traits recorded at different times, direct additive correlation estimates ranging from 0·18 to 0·55 in contrast to estimates of 0·38 to 0·65 for correlations with heart girth at weaning.

scholarly journals Maternal genetic effects on body weight and breast morphological traits in duck population under selection

2010 ◽  
Vol 53 (5) ◽  
pp. 600-608
Author(s):  
T. Szwaczkowski ◽  
M. Grzech ◽  
A. Borowska ◽  
E. Wencek ◽  
A. Wolc
Keyword(s):  
Body Weight ◽  
Animal Models ◽  
Maternal Effects ◽  
Morphological Traits ◽  
Genetic Model ◽  
Information Criterion ◽  
Genetic Effects ◽  
Additive Genetic Model ◽  
Heritability Estimates ◽  
Crest Length

Abstract. Direct and maternal additive genetic and mitochondrial variances of duck meat performance traits were estimated using AI-REML algorithm. Records of 3 099 (5 010 pedigreed birds) from six consecutive generations were included. The following four traits were investigated: body weight at 3rd week, body weight at 7th week, sternum crest length at 7th week (in cm), and breast muscles thickness at 7th week (in cm). The data were analysed via three single trait linear animal models: I – additive genetic model, II – model extended to additive maternal effects; III– as model II with mitochondrial effects as random. Adequacy of the models was examined by Akaike´s information criterion (AIC). Relatively high direct additive heritability estimates were obtained for body weight at 3rd week (0.4326–0.4546) and body weight at 7th week (0.5322–0.6088) whereas lower estimates were obtained for sternum crest length (0.1756–0.2744) and breast muscles thickness (0.1369–0.2932). The maternal heritabilities were moderate and also considerably depended on the model used. For all of the studied traits a negative covariance between direct and maternal genetic effects was found. Mitochondrial heritabilities were very low. Generally, on the basis of criteria employed, the model III can be suggested for analysis of body weight whereas for other traits model II seems to be suitable.

scholarly journals Estimates of direct, maternal and grandmaternal genetic effects for growth traits in Gobra cattle

1999 ◽  
Vol 22 (3) ◽  
pp. 363-367 ◽  
Author(s):  
M. Diop ◽  
J. Dodenhoff ◽  
L.D. Van Vleck
Keyword(s):  
Animal Models ◽  
Genetic Correlation ◽  
Random Effects ◽  
Maternal Effects ◽  
Environmental Effects ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Effects ◽  
Average Information

Estimates of genetic parameters for birth (N = 3909), weaning (N = 3425), yearling (N = 2764) and final (N = 2144) weights were obtained from the records of Gobra cattle collected at the Centre de Recherches Zootechniques de Dahra, Senegal. Three animal models were fitted to obtain estimates by REML using an average information (AI) approach. Model 1 considered random direct, maternal genetic and maternal permanent environmental effects. In model 2, a general grandmaternal effect was added to the random effects considered in model 1, and in model 3, the general grandmaternal effect was divided into grandmaternal genetic and grandmaternal permanent environmental effects. All models allowed covariances among genetic effects. The inclusion of grandmaternal effects in models 2 and 3 did not change the estimates of the genetic parameters compared to model 1. Variances attributable to grandmaternal effects became negative and were set close to zero, except for yearling weight for which grandmaternal heritability was 0.03 ± 0.03. The estimates for direct and maternal heritabilities were, respectively, 0.08 ± 0.03 and 0.03 ± 0.02 for birth, 0.20 ± 0.05 and 0.21 ± 0.05 for weaning, 0.26 ± 0.07 and 0.16 ± 0.07 for yearling and 0.14 ± 0.06 and 0.16 ± 0.06 for final weights. The estimates of the genetic correlation between direct and maternal effects for birth, weaning, yearling and final weights were -0.17 ± 0.40, -0.58 ± 0.32, -0.52 ± 0.34 and -0.34 ± 0.37, respectively. For yearling weight with grandmaternal heritability estimated to be only 0.03, model 3 gave estimates of the genetic correlation between direct and grandmaternal effects and between maternal and grandmaternal effects of 0.28 ± 0.48 and -0.33 ± 0.67, respectively. Estimates of direct and maternal heritabilities were unchanged when grandmaternal effects were not included in the model.

Genetic and maternal effects on juvenile survival and fitness-related traits in three populations of Atlantic salmon

2015 ◽  
Vol 72 (5) ◽  
pp. 751-758 ◽  
Author(s):  
Aimee Lee S. Houde ◽  
Craig A. Black ◽  
Chris C. Wilson ◽  
Trevor E. Pitcher ◽  
Bryan D. Neff
Keyword(s):  
Atlantic Salmon ◽  
Maternal Effects ◽  
Environmental Effects ◽  
Genetic Architecture ◽  
Life Stage ◽  
Random Mating ◽  
Genetic Effects ◽  
Phenotypic Variance ◽  
Offspring Performance ◽  
Additive Genetic Effects

Although studies addressing natural selection have primarily focused on additive genetic effects because of their direct relationship with responses to selection, nonadditive genetic and maternal effects can also significantly influence phenotypes. We partitioned the phenotypic variance of survival and fitness-related traits in juvenile Atlantic salmon (Salmo salar) from three allopatric populations (LaHave, Sebago, and Saint-Jean) into additive genetic, nonadditive genetic, and maternal environmental effects using a full-factorial breeding design. We also modelled the potential increase in offspring performance if nonrandom mating (e.g., mate choice) is considered instead of random mating. The three populations exhibited significant differences in trait values as well as the genetic architecture of the traits. Nevertheless, nonadditive genetic and maternal environmental effects tended to be larger than the additive genetic effects. There was also a shift from maternal environmental to genetic effects during development in two of the populations. That is, maternal environmental effects were larger at early (egg and alevin) life stages, whereas nonadditive effects were larger at the later (fry) life stage. The amount of additive genetic effects was small, suggesting the traits will respond slowly to selection. We discuss how different maternal environmental effects across years may influence the genetic architecture of offspring traits.

Abstract MP59: Revisiting Heritability Accounting For Common Environmental Effects And Maternal Inheritance

Circulation ◽  
2014 ◽  
Vol 129 (suppl_1) ◽  
Author(s):  
Chunyu Liu ◽  
Josée Dupuis ◽  
Martin G Larson ◽  
L. Adrienne Cupples ◽  
Jose M M Ordovas ◽  
...  
Keyword(s):  
Maternal Effects ◽  
Environmental Effects ◽  
Variance Components ◽  
Maternal Inheritance ◽  
Mitochondrial Inheritance ◽  
Pedigree Data ◽  
Extended Pedigrees ◽  
Heart Study ◽  
Heritability Estimates ◽  
Average Gene

Background: Heritability measures the proportion of phenotypic variation attributable to genetic factors. Reliable heritability estimates are used to determine the necessary sample size and power for subsequent genetic studies of susceptibility genes. In addition to a shared nuclear genetic component, common environmental factors and maternal or mitochondrial inheritance may have strong effects on some phenotypes. Failure to account for necessary variance components may give rise to biased heritability estimates. Aims: Our primary goal was to investigate how heritability estimates are biased in the presence of common environmental or/and maternal effects. The second goal was to estimate mitochondrial inheritance for a number of common phenotypes. Methods: We employed variance component methods to account for additional variance components using both simulated and Framingham Heart Study (FHS) pedigree data to revisit heritability estimates in the presence of common environmental and maternal effects. Results: Using both simulated families and actual FHS extended pedigrees, we demonstrated that heritability is greatly overestimated when key variance components are not properly accounted for. The inflation in heritability ranged from 9% to 214% across several anthropometric, metabolic and life-style phenotypes when we compared models that consider correct variance components and simple models that only consider familial relationships (Table 1). Maternal inheritance was observed in most phenotypes investigated. The estimated maternal inheritance ranged from ~1 to 5%, which is considerable because the mitochondrial genome is about the size of an average gene. Conclusion/Discussion: We systematically investigated the influence of common environmental effects and maternal inheritance in heritability estimates using extended pedigrees. Our findings may explain, in part, the missing heritability for some traits and may facilitate further collaborations in the genetic study of mitochondrial DNA in disease susceptibility for common phenotypes.

Egg weight and reproduction traits in laying hens: estimation of direct and maternal genetic effects using Bayesian approach via Gibbs sampling

2000 ◽  
Vol 70 (1) ◽  
pp. 9-16 ◽  
Author(s):  
A. Sewalem ◽  
K. Johansson
Keyword(s):  
Gibbs Sampling ◽  
Maternal Effects ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
Genetic Effects ◽  
Egg Weight ◽  
Zygote Development ◽  
Reproduction Traits ◽  
Female Reproductive Traits ◽  
Weight Trait

AbstractFertility, generally considered as a trait of the two parents, is perhaps best defined as the interaction between the male and female gametes in the production of a viable zygote. Although zygote development and hatchability are traits of the embryo influenced by maternal effects, in most previous studies they have been considered to be female reproductive traits. The aim of this work was to study the influence of sire on fertility and hatchability traits and to estimate the (co)variance components of direct and maternal genetic effects under a Bayesian setting via Gibbs sampling. We measured the fertility of 6396 eggs and the hatchability of 5393 embryos on an individual basis. In addition, egg weight from 42 to 63 weeks of age (EW63) was recorded on an individual egg basis. The sire accounted for a significant amount of the variation infertility and hatchability. For direct heritability, the marginal posterior mean, for fertility and hatchability were almost equal (0·24). The maternal heritabilities for fertility and hatchability were 0·20 and 0·18, respectively. The direct heritability value for the egg weight trait was high. The direct-direct genetic correlation between egg weight and hatchability was negative and significant. The genetic correlations between the direct effect of the egg weight trait and maternal effects for fertility and hatchability were low, with variable signs, and were not significant. On the other hand, significant negative genetic correlations between direct and maternal effects of fertility and hatchability were obtained (the posterior means were –0·56 for FE and –0·55 for HC).

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