Morry D W, Ts'o P O
Mutat Res. 1980 Apr;70(2):221-9. doi: 10.1016/0027-5107(80)90162-1.
The ploidy dependence of the induced frequency of a phenotype can be used to determine the dominant or recessive nature of a somatic mutation to a given trait. To demonstrate this we induced mutations in diploid and spontaneously occurring tetraploid clones of Syrian hamster embryo cells by treatment with EMS (1.2 mg/ml, 4 h). Mutagenized cells were assayed for the recessive mutation to 6-thioguanine resistance (5 micrograms/ml) and the dominant mutation to ouabain resistance (1.2 mM). The frequency of induction of the dominant mutation was equal in the diploid and tetraploid clones (2.3 x 10(-4)). The frequency of induction of the recessive mutation was greatly reduced in the tetraploid clone relative to the diploid clone (1.8 x 10(-4) vs. 1.2 x 10(-3)). 6TGr mutant subclones from the tetraploid clone remain nearly tetraploid, or even increase in ploidy, but show a reduction in the number of X chromosomes from two to one, or in some cases none (based on chromosome morphology). The principle of ploidy dependence is now being used to study the induction of phenotypes related to neoplastic transformation.
表型诱导频率的倍性依赖性可用于确定体细胞突变对给定性状的显性或隐性性质。为了证明这一点，我们用EMS（1.2mg/ml，4小时）处理叙利亚仓鼠胚胎细胞的二倍体和自发产生的四倍体克隆，诱导突变。对诱变细胞进行检测，以确定对6-硫鸟嘌呤抗性（5μg/ml）的隐性突变和对哇巴因抗性（1.2mM）的显性突变。二倍体和四倍体克隆中显性突变的诱导频率相等（2.3×10^(-4)）。四倍体克隆中隐性突变的诱导频率相对于二倍体克隆大大降低（1.8×10^(-4)对1.2×10^(-3)）。来自四倍体克隆的6TGr突变亚克隆几乎保持四倍体，甚至倍性增加，但X染色体数量从两条减少到一条，或在某些情况下没有（基于染色体形态）。倍性依赖性原理现在正被用于研究与肿瘤转化相关的表型诱导。
