Estimates of individual
additive genetic variance ([[sigma].sup.2.sub.a]) were lower than the environmental variances, especially the residual variance ([[sigma].sup.2.sub.e]).
Additive genetic variance ([[sigma].sup.2.sub.a]), residual variance ([[sigma].sup.2.sub.e]) and phenotypic variance ([[sigma].sup.2.sub.p]) for milk yield MY), fat yield (FY), and protein yield (PY) for Region 1, Region 2, and Region 3 Items [[sigma].sup.2.sub.a] [[sigma].sup.2.sub.e] MY Region 1 555,716.51 2,043,254.33 Region 2 504,443.32 1,929,089.12 Region 3 368,608.08 1,952,364.42 FY Region 1 786.91 2,386.74 Region 2 792.87 2,345.70 Region 3 480.05 2,363.86 PY Region 1 380.47 1,850.1 1 Region 2 363.63 1,838.68 Region 3 211.02 1,872.70 Items [[sigma].sup.2.sub.p] MY Region 1 2,598,970.84 Region 2 2,433,532.44 Region 3 2,320,972.50 FY Region 1 3,173.65 Region 2 3,138.56 Region 3 2,843.91 PY Region 1 2,230.58 Region 2 2,202.31 Region 3 2,083.71 Table 2.
Variance component and genetic parameters: The direct
additive genetic variance was peak at the later ages in the growth path (Table 3).
The same authors argue that the inability to properly model the contribution of maternal genetic effects may result in an overestimation of the
additive genetic variance and, therefore, an overestimation of heritability.
It is known that small populations give imprecise estimates of
additive genetic variance and heritability, and the high standard errors on variances and heritabilities in this study illustrate this point.
A,
additive genetic variance component; E, unique environmental variation.
First, as derived by Knapp and Bridges (1990), an additional clonal replicate of a progeny can increase statistical power, which is analogous to adding another progeny genotype if all the
additive genetic variance is explained by markers (this condition may be partially met because the significant markers I identified accounted for large percentages of the genetic variance; see Results).
Non-iterative least square weighted analysis was applied for goodness of fit for genetic (
additive genetic variance DR and dominance HR) and two environmental (within family environment E1 and between family environment E2) components.
We were then also able to determine the intensity of selection, the heritability, and the
additive genetic variance of development time separately for each sex.
Experimental and theoretical results showed that
additive genetic variance can increase with inbreeding in some circumstances such as those reported by those authors, when they simulated two scenarios in a population with a Ne equal to 50.
Figure 2 shows estimates of
additive genetic variance and heat tolerance variance with increasing THI.
(2008) showed that the first three eigenvalues and related eigenfunctions illustrate the highest
additive genetic variance. If the amount of first eigenvalue was considerable, selection could generate rapid change in the characteristic that was under selection process (Kirkpatrick et al., 1990; Olori et al., 1999).
here, [g.sub.11]:
additive genetic variance for direct effects of animal, [g.sub.12] and [g.sub.21]: additive genetic covariance between direct and maternal effects, [g.sub.22]:
additive genetic variance for maternal effects, [[sigma].sup.2.sub.pe]: variance of random maternal permanent environmental effects, [[sigma].sup.2.sub.e]: variance of remaining random effects, and A and I are matrices of relationships and Identity matrices, respectively.
