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.

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.

The Heritability of Life Events: An Adolescent Twin and Adoption Study

2008 ◽  
Vol 11 (3) ◽  
pp. 257-265 ◽  
Author(s):  
Heather R. Bemmels ◽  
S. Alexandra Burt ◽  
Lisa N. Legrand ◽  
William G. Iacono ◽  
Matt McGue
Keyword(s):  
Life Events ◽  
Environmental Effects ◽  
Twin Studies ◽  
Specific Effect ◽  
Genetic Effects ◽  
Adolescent And Young Adult ◽  
Adoption Study ◽  
Independent Events ◽  
Biometrical Models ◽  
Additive Genetic Effects

AbstractAlthough life events are often conceptualized as reflecting exogenous risk factors for psychopathology, twin studies have suggested they are heritable. We undertook a mixed twin/adoption study to further explore genetic and environmental contributions to individual differences in the experience of life events. Specifically, a sample of 618 pairs of like-sex adolescent twins, 244 pairs of like-sex adopted adolescent and young adult siblings, and 128 pairs of like-sex biological siblings completed a life events interview. Events were classified as independent (not likely to have been influenced by respondent's behavior), dependent (likely to have been influenced by respondent's behavior), or familial (experienced by a family member), and then summed to form three life event scales. Variance on the scales was assumed to be a function of four factors: additive genetic effects (a2), shared environmental effects (c2), twin-specific effects (t2), and nonshared environmental effects (e2). Data were analyzed using standard biometrical models. Shared environmental effects were found to be the largest contributor to variance in familial events (c2 = .71; 95% confidence interval of .65, .76); additive genetic effects were the largest contributor to dependent events (a2 = .45; CI = .31, .58); and nonshared environmental effects were found to be the largest contributor independent events (e2 = .57; CI = .51, .64). A significant twin-specific effect was also found for independent life events, indicating that twins are more likely to be exposed to such events than non-twin biological siblings. Findings are discussed in terms of their implication for understanding the nature of psychosocial risk.

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.

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.

Estimates of genetic parameters for growth traits of Gobra cattle

1998 ◽  
Vol 66 (2) ◽  
pp. 349-355 ◽  
Author(s):  
M. Diop ◽  
L. D. Van Vleck
Keyword(s):  
Animal Models ◽  
Maternal Effects ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Random Effect ◽  
Random Effect Model ◽  
Genetic Effects ◽  
Breeding Value ◽  
Effect Model ◽  
Additive Genetic Effects

AbstractEstimates of (co)variance components and genetic parameters were obtained for birth (no. = 3909), weaning (no. = 3425), yearling (no. = 2763), and final weight (no. = 2142) for Gobra cattle at the Centre de Recherches Zootechniques de Dahra (Senegal), using single trait animal models. Data were analysed by restricted maximum likelihood. Four different animal models were fitted for each trait. Model 1 considered the animal as the only random effect. Model 2 included in addition to the additive direct effect of the animal, the environmental effect due to the dam. Model 3 added the maternal additive genetic effects and allowed a covariance between the direct and maternal genetic effects. Model 4 fitted both maternal genetic and permanent environmental effects. Inclusion of both types of maternal effects (genetic and environmental) provided a better fit for birth and weaning weights than models with one maternal effect only. For yearling and final weights, the improvement was not significant. Important maternal effects werefound for all traits. Estimates of direct heritabilities were substantially higher when maternal effects were ignored. Estimates of direct and maternal heritabilities with model 4 were 0·07 (s.e. 0·03) and 0·04 (s.e. 0·02), 0·20 (s.e. 0·05) and 0·21 (s.e. 0.05), 0·24 (s.e. 0·07) and 0·21 (s.e. 0·06), and 0·14 (s.e. 0·06) and 0.16 (s.e. 0·06) for birth, weaning, yearling and final weights, respectively. Correlations between direct and maternal genetic effects were negative for all traits, and large for weaning and yearling weights with estimates of -0·61 (s.e. 0·33) and -0·50 (s.e. 0·31), respectively. There was a significant positive linear phenotypic trend for weaning and yearling weights. Linear trends for additive direct and maternal breeding values were not significant for any trait except maternal breeding value for yearling weight.

scholarly journals Partitioning variation in measurements of beef carcass traits using ultrasound1

2020 ◽  
Vol 4 (3) ◽  
Author(s):  
Bradie M Schmidt ◽  
Michael G Gonda ◽  
Michael D MacNeil
Keyword(s):  
Animal Models ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Subcutaneous Fat ◽  
Genetic Effects ◽  
Residual Variance ◽  
Phenotypic Variance ◽  
Contemporary Group ◽  
Genetic Evaluations ◽  
Additive Genetic Effects

Abstract Ultrasound technology provides cattle breeders with a quick, noninvasive, and inexpensive way to measure carcass data on live animals. Ultrasound data are used as indicator traits in cattle genetic evaluations for economically relevant carcass traits. Ultrasound cattle genetic evaluations assume homogeneous additive genetic and residual variance. Thus, the objective was to partition phenotypic variance in ultrasound carcass measurements into components for additive genetic effects, technicians, contemporary groups within technicians, and residual and to examine the homogeneity of these variances among image interpretation laboratories. Records of longissimus muscle area (LMA), percentage of intramuscular fat (IMF), and subcutaneous fat depth (SFD), measured using ultrasound, were provided by the American Angus Association (n = 65,967), American Hereford Association (n = 43,182), and American Simmental Association (n = 48,298). The data also included contemporary group, technician, imaging lab, and a three-generation pedigree for each animal. Variance components for ultrasound carcass measurements were first estimated with univariate animal models for each breed and imaging laboratory using derivative-free restricted maximum likelihood. Then, treating data from each imaging laboratory as separate traits, genetic correlations between laboratories for LMA, percentage of IMF, and subcutaneous fat were estimated with trivariate animal models. The technician explained 12–27%, 5–23%, and 4–26% of the variance for IMF, SFD, and LMA, respectively, across all three breeds. Variance due to technician was often greater than variance due to additive genetic effects but almost always less than that explained by the contemporary group. Within breeds, estimates of additive genetic variance for LMA, SFD, and IMF differed (range divided by mean) among laboratories by 4.5%, 21.5%, and 39.4 % (Angus); 31.6%, 15.0%, and 49.1% (Hereford); and 19.9%, 46.6%, and 55.3% (Simmental), respectively. Likewise, estimates of residual variance for LMA, SFD, and IMF differed among laboratories by 43.4%, 22.9%, and 43.3% (Angus); 24.9%, 15.2%, and 79.2% (Hereford); and 26.4%, 32.5%, and 46.2% (Simmental), respectively. Genetic correlations between labs across breeds ranged from 0.79 to 0.95 for IMF, 0.26 to 0.94 for SFD, and 0.78 to 0.98 for LMA. The impact of the observed heterogeneity of variance between labs on genetic evaluation requires further study.

565. A study of variation in twin cattle: III. Growth

1955 ◽  
Vol 22 (1) ◽  
pp. 1-9 ◽  
Author(s):  
J. W. B. King ◽  
H. P. Donald
Keyword(s):  
Environmental Effects ◽  
Live Weight ◽  
Genetic Effects ◽  
Point Of View ◽  
Environmental Variance ◽  
Simple Assumption ◽  
Polynomial Coefficients ◽  
Straight Line ◽  
Best Fitting ◽  
Additive Genetic Effects

1. Polynomial coefficients have been fitted to data on growth in live weight to 19 months and on height at withers to 27 months of age shown by one-egg (MZ) and two-egg (DZ) twins and pairs of half-sisters (HZ). The coefficients obtained (a0, a2 and a3) have been subjected to analysis of variance.2. For growth in live weight, the ratio of intrapair variances for MZ, DZ and HZ pairs was 1:6·8:10 for a1, which gives the straight line best fitting the observed curve. Unrelated pairs, it is calculated, would have had an intrapair variance 20·9 times as great as MZ pairs. From the point of view of minimizing the intrapair variance, the advantage of the MZ pairs was usually a little less for a0, and considerably less for a2 and a3.3. For height at withers, the results were similar to those for weight.4. The contribution of environmental variance to total intrapair variance increased from a0 to a3, while that due to additive genetic effects diminished. Owing to the wide fiducial limits applicable, the results can be accommodated assuming only additive genetic effects in addition to environmental effects as estimated from one-egg twins. The extent to which HZ pairs exceeded the variance expected, however, suggests that this simple assumption may prove inadequate.

Bayesian analysis of direct and maternal effects for birthweight in Iranian buffaloes using Gibbs sampling

2016 ◽  
Vol 56 (5) ◽  
pp. 859 ◽  
Author(s):  
Navid Ghavi Hossein-Zadeh
Keyword(s):  
Animal Model ◽  
Gibbs Sampling ◽  
Maternal Effects ◽  
Threshold Model ◽  
Genetic Selection ◽  
Genetic Effects ◽  
Phenotypic Variance ◽  
Environmental Variance ◽  
Selection Decisions ◽  
Estimate Variance

Calving records from April 1994 to March 2010 comprising 8570 calving events from the first three parities of 734 buffalo herds of Iran were analysed using a linear animal model to estimate variance components and heritability for birthweight. A linear animal model including direct and maternal genetic effects with covariance between them and maternal permanent environmental effect was implemented by Gibbs sampling methodology. A single Gibbs sampling chain with 500 000 rounds was generated by the Threshold Model program. Posterior means of direct and maternal heritabilities and repeatability for birthweight were 0.21, 0.15 and 0.23, respectively. Estimate of correlation between direct and maternal genetic effects for birthweight was –0.71. Also, the ratio of permanent environmental variance to phenotypic variance was 0.02. Along with the direct genetic effects, the contribution of maternal effects to the phenotypic variance of birthweight may provide producers with information to optimally use the reported estimates when making selection decisions. The results of this study indicated that exploitable genetic variation observed for birthweight could be considered in designing future selection programs for Iranian buffaloes and improvement in birthweight could be attained by genetic selection.

scholarly journals Genetic analysis of milk yield, fat and protein content in Holstein dairy cows in Iran: Legendre

2013 ◽  
Vol 56 (1) ◽  
pp. 497-508
Author(s):  
R. Abdullahpour ◽  
M. M. Shahrbabak ◽  
A. Nejati-Javaremi ◽  
R. V. Torshizi ◽  
R. Mrode
Keyword(s):  
Protein Content ◽  
Milk Yield ◽  
Environmental Effects ◽  
Milk Fat ◽  
Legendre Polynomials ◽  
Fat Content ◽  
Genetic Effects ◽  
Residual Variance ◽  
Genetic Trend ◽  
Additive Genetic Effects

Abstract. Data including 219 105 test day records of 22 569 first parity Holstein cows in 56 herds were analysed for milk yield, fat content and protein content. Legendre polynomials were used in a random regression model to explain traits curves, additive genetic and permanent environmental effects along days in milk (DIM). Legendre polynomials of order 3 were used to describe additive genetic effects on the traits. For permanent environmental effects, for milk the order of 6 and for fat and protein content the order of 4 were used. Heterogeneity of residual variance was considered. Restricted maximum likelihood (REML) methodology was used to estimate the required parameters. Variations in genetic, permanent environment and residual effects and heritability changes along DIM were computed and illustrated. Daily heritability estimates averaged as 0.22, 0.14 and 0.23 for milk, fat and protein contents, respectively. Minimum correlations between DIM for additive genetic effects were as 0.49, −0.01 and 0.34 for milk, fat and protein contents. There were higher genetic correlations between test day milk yield and protein content compared to fat content. The genetic trend of milk yield has increased over the years from 1971 to 2005, while the genetic trend for fat and protein content declined.

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