Holson J F, Scott W J, Gaylor D W, Wilson J G
Teratology. 1976 Oct;14(2):135-41. doi: 10.1002/tera.1420140204.
Rats were mated for two or 15 hours and variability of day-12-embryos in weight, protein content, and [3H]thymidine incorporation was compared in the long mating period (LMP) and short mating period (SMP) groups by a 2-level nested analysis of variance. Variability in day-20 fetal weight was similarly compared. In both groups day-12 embryonic weight was relatively more variable than day-20 fetal weight, and variability was less in SMP than LMP animals for each comparison made, although statistical significance was attained only for thymidine incorporation. ""Litter effects'' were noted but not of the magnitude reported by other investigators. It was concluded that inappropriate statistical methods have encouraged the belief that among-litter variability usually exceeds within-litter fetal weight variability. The teratological implications of reduced development variability and the ""litter effect'' are discussed.
将大鼠交配2小时或15小时，通过二级嵌套方差分析比较长交配期（LMP）和短交配期（SMP）组中第12天胚胎在体重、蛋白质含量和[3H]胸腺嘧啶核苷掺入方面的变异性。同样比较了第20天胎儿体重的变异性。在两组中，第12天胚胎体重的变异性相对大于第20天胎儿体重的变异性，并且在每次比较中，SMP动物的变异性均小于LMP动物，尽管仅在胸腺嘧啶核苷掺入方面达到统计学显著性。观察到了“窝效应”，但其程度低于其他研究者报道的水平。得出的结论是，不恰当的统计方法助长了这样一种观点，即窝间变异性通常超过窝内胎儿体重变异性。讨论了发育变异性降低和“窝效应”的致畸学意义。
