Eisen E J, Prasetyo H
Dept. of Anim. Sci., North Carolina State University, Raleigh 27695-7621.
J Anim Sci. 1988 May;66(5):1153-65. doi: 10.2527/jas1988.6651153x.
Heritabilities (ĥ2) and genetic correlations (rG) were estimated by regression of offspring on sire in two replicate, unselected lines of mice. Traits were associated with growth, feed efficiency, fat deposition and lean tissue. The ĥ2 for growth traits ranged from .34 to .42, except for 3-wk body weight, which was only .05. The ĥ2 for feed efficiency was .28. Ranges in ĥ2 were .45 to .50 for fat deposition traits and .36 to .42 for lean tissue traits. The rG involving 3-wk to 6-wk feed efficiency with hind carcass and fat measurements at 12 wk were small. Antagonisms were found between the sign of rG and the direction of usual breeding goals for pairs of traits (e.g., rG greater than 0 between fat deposition and hind carcass weight and rG less than 0 between hind carcass as a percentage of body weight and body weight). Selection indexes were developed to counteract these antagonisms. Modified selection indexes were compared where responses in individual traits rather than the aggregate breeding value were of major importance. The aggregate breeding values and selection indexes included: 1) epididymal fat pad weight and body weight, 2) hind carcass weight and body weight, or 3) all three traits. Economic weights in retrospect were calculated for the modified selection indexes. In some cases, expected correlated responses in component traits were not influenced greatly over a wide range of ratios of economic weights, but in other cases the component traits changed sharply over a narrow range of ratios.
在两个重复的、未经过选择的小鼠品系中，通过子代对父本的回归分析来估计遗传力（ĥ2）和遗传相关性（rG）。这些性状与生长、饲料效率、脂肪沉积和瘦肉组织有关。生长性状的ĥ2范围为0.34至0.42，但3周龄体重的ĥ2仅为0.05。饲料效率的ĥ2为0.28。脂肪沉积性状的ĥ2范围为0.45至0.50，瘦肉组织性状的ĥ2范围为0.36至0.42。3周龄至6周龄饲料效率与12周龄后躯胴体及脂肪测量值之间的rG较小。在成对性状的rG符号与常规育种目标方向之间发现了拮抗作用（例如，脂肪沉积与后躯胴体重量之间的rG大于0，而后躯胴体占体重的百分比与体重之间的rG小于0）。制定了选择指数以抵消这些拮抗作用。比较了修改后的选择指数，其中个体性状的反应而非综合育种值更为重要。综合育种值和选择指数包括：1）附睾脂肪垫重量和体重，2）后躯胴体重量和体重，或3）所有三个性状。回顾性地计算了修改后选择指数的经济权重。在某些情况下，经济权重比例在很宽范围内变化时，组成性状的预期相关反应受影响不大，但在其他情况下，组成性状在较窄的权重比例范围内变化剧烈。
