Piegorsch W W, Margolin B H, Shelby M D, Johnson A, French J E, Tennant R W, Tindall K R
Department of Statistics, University of South Carolina, Columbia 29208, USA.
Environ Mol Mutagen. 1995;25(3):231-45. doi: 10.1002/em.2850250310.
Design features that adjust and account for excess variation in a transgenic mouse mutation assay based on a lacI target transgene from E. coli are considered. These features include proper identification of plate, packaging reaction, and animal identifier codes throughout the experimental and analysis phases of the study, "blocking" of exposed and unexposed animals when preparing and plating multiple packaging reactions from the same genomic DNA sample, separating sectored mutant plaques and complete mutant plaques before performing any quantitative analyses, and testing for sources of excess variation attributable to features of the experimental protocol--such as plate-to-plate (within packaging reactions), packaging reaction-to-packaging reaction (within animals), and animal-to-animal (within study). Control and ethylnitrosourea-treated animal data are presented from a fully designed study in the lacI assay. The study design incorporates many of these experimental principles. Statistical methods to identify excess variability are noted, and the designed study data are used to illustrate the types of variability encountered in practice. A standard statistical test for two-sample testing is highlighted, from which recommendations are made for sample size selection in future studies.
本文考虑了基于大肠杆菌lacI靶基因的转基因小鼠突变试验中，用于调整和解释过度变异的设计特征。这些特征包括在研究的实验和分析阶段，正确识别平板、包装反应和动物识别码；当从同一基因组DNA样本制备和铺板多个包装反应时，对暴露和未暴露动物进行“分组”；在进行任何定量分析之前，分离扇形突变噬菌斑和完整突变噬菌斑；以及测试实验方案特征（如平板间（在包装反应内）、包装反应间（在动物内）和动物间（在研究内））导致的过度变异来源。本文展示了lacI试验中一项完整设计研究的对照和乙基亚硝基脲处理动物的数据。该研究设计纳入了许多这些实验原则。文中指出了识别过度变异的统计方法，并使用设计研究数据来说明实际中遇到的变异类型。重点介绍了一种用于双样本检验的标准统计测试，并据此对未来研究中的样本量选择提出了建议。
