Nielsen M K, Jones L D, Freking B A, DeShazer J A
Department of Animal Science, University of Nebraska-Lincoln 68583-0908, USA.
J Anim Sci. 1997 Jun;75(6):1461-8. doi: 10.2527/1997.7561461x.
Divergent selection for heat production/loss (kcal.kg-.75.d-1), measured in 9- to 11-wk-old male mice, was conducted for 15 generations. Heat loss was measured for 15 h on individual animals placed overnight in direct, gradient-layer calorimeters. Selection for high (MH) and low (ML) heat loss and unselected control (MC) occurred in each of three replicates for a total of nine unique lines. Repeatability of the heat loss measurement was .45 and the CV was 10.5%. Cumulative realized selection differentials, averaged for the three replicates, were 145.1 and -105.0 (kcal.kg-.75.d-1) and ranged from 136.9 to 149.2 and -17.1 to -101.3 for MH and ML selection, respectively. Cumulative standardized realized selection differentials, averaged for the three replicates, were 10.06 and -9.51 for MH and ML selection, respectively. Direct responses (kcal.kg-.75.d-1) in heat loss after 15 generations were 44.2 for MH and -27.4 for ML as deviations from MC. Asymmetry of response was evident (P = .03) by Generation 10. Realized heritability was .28 +/- .01 based on divergence of MH and ML selection. For selection for higher and lower heat loss, realized heritabilities were .31 +/- .01 and .26 +/- .01, respectively.
对9至11周龄雄性小鼠测量的产热/散热（千卡·千克⁻⁰.⁷⁵·天⁻¹）进行了15代的分化选择。将个体动物置于直接梯度层热量计中过夜，测量其15小时的散热情况。在三个重复组中分别进行高散热（MH）、低散热（ML）选择和未选择的对照（MC），共产生九条独特的品系。散热测量的重复性为0.45，变异系数为10.5%。三个重复组的平均累积实际选择差分别为145.1和-105.0（千卡·千克⁻⁰.⁷⁵·天⁻¹），MH和ML选择的范围分别为136.9至149.2以及-17.1至-101.3。三个重复组的平均累积标准化实际选择差，MH和ML选择分别为10.06和-9.51。15代后，与MC相比，MH的散热直接反应（千卡·千克⁻⁰.⁷⁵·天⁻¹）为44.2，ML为-27.4。到第10代时，反应的不对称性明显（P = 0.03）。基于MH和ML选择的差异，实际遗传力为0.28±0.01。对于更高和更低散热的选择，实际遗传力分别为0.31±0.01和0.26±0.01。
