An examination of adaptive reversion in Saccharomyces cerevisiae.
An examination of adaptive reversion in Saccharomyces cerevisiae.
复制标题
DOI：
--
复制
发表时间：
1992-09
期刊：
影响因子：
3.3
通讯作者：
D. F. Steele;S. Jinks-Robertson
中科院分区：
文献类型：
--
作者：
D. F. Steele;S. Jinks-Robertson
在含有确定的lys2移码突变的单倍体酵母菌株中，已经检查了回复为Lys+原养型。当将细胞接种在仅缺乏赖氨酸的合成完全培养基上时，在细胞数量没有任何可检测到的增加的情况下，Lys+回复突变菌落的数量以时间依赖性方式累积。对独立培养物中早期出现的赖氨酸+菌落数量分布的检查表明，原养型突变在非选择性生长期间随机发生。相比之下，对后期出现的赖氨酸+菌落分布的检查表明，潜在的回复突变事件发生在选择性平板接种后。在选择性接种Lys+回复突变体之前，当细胞缺乏色氨酸、亮氨酸或赖氨酸和色氨酸时，未发生Lys+回复突变体的蓄积。这些结果表明，当突变赋予选择优势时，突变会更频繁地积累，因此与酵母中适应性突变的发生一致。
Reversion to Lys+ prototrophy in a haploid yeast strain containing a defined lys2 frameshift mutation has been examined. When cells were plated on synthetic complete medium lacking only lysine, the numbers of Lys+ revertant colonies accumulated in a time-dependent manner in the absence of any detectable increase in cell number. An examination of the distribution of the numbers of early appearing Lys+ colonies from independent cultures suggests that the mutations to prototrophy occurred randomly during nonselective growth. In contrast, an examination of the distribution of late appearing Lys+ colonies indicates that the underlying reversion events occurred after selective plating. No accumulation of Lys+ revertants occurred when cells were starved for tryptophan, leucine or both lysine and tryptophan prior to plating selectively for Lys+ revertants. These results indicate that mutations accumulate more frequently when they confer a selective advantage, and are thus consistent with the occurrence of adaptive mutations in yeast.