Ploidy evolution in the yeast Saccharomyces cerevisiae:: a test of the nutrient limitation hypothesis
Ploidy evolution in the yeast Saccharomyces cerevisiae:: a test of the nutrient limitation hypothesis
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DOI：
10.1046/j.1420-9101.2001.00245.x
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发表时间：
2001-01-01
影响因子：
2.1
通讯作者：
Mable, BK
中科院分区：
文献类型：
--
作者：
Mable, BK
营养限制假说为单倍体和二倍体生命周期的进化提供了一种非一般的解释：在某些营养限制条件下，营养需求和摄取的差异使单倍体能够超越二倍体提供的潜在遗传优势。测定了在交配型位点上相同的单倍体、二倍体和四倍体酵母细胞的相对适合度。在四种环境条件下，通过对共同竞争对手的生长速率和孤立培养物的内在生长速率来衡量适应度：(1)富培养基（YPD），首选生长温度（30℃）；(2) 30度的贫营养培养基（MM）；(3)在非首选温度（37℃）下YPD；(4) MM为37°c。与营养限制假说的预测相反，在营养丰富的条件下，单倍体的生长速度明显快于二倍体，但在相对竞争能力决定适应度时，两者之间没有明显差异。此外，温度对单倍体和二倍体的相对生长有影响，单倍体在较高温度下的生长速度相对较快。相比之下，四倍体在所有条件下的表现都很差。在测量的条件下，细胞几何参数不是一致的适应度预测因子。
The nutrient limitation hypothesis provides a nongeneric explanation for the evolution of life cycles that retain both haploid and diploid phases: differences in nutrient requirements and uptake allow haploids to override the potential genetic advantages provided by diploidy under certain nutrient limiting conditions. The relative fitness of an isogenic series of haploid, diploid and tetraploid yeast cells (Saccharomyces cerevisiae), which were also equivalent at the mating type locus, was measured. Fitness was measured both by growth rate against a common competitor and by intrinsic growth rate in isolated cultures, under four environmental conditions: (1) rich medium (YPD) at the preferred growth temperature (30 degreesC); (2) nutrient poor medium (MM) at 30 degreesC; (3) YPD at a nonpreferred temperature (37 degreesC); and (4) MM at 37 degreesC. In contrast to the predictions of the nutrient limitation hypothesis, haploids grew significantly faster than diploids under nutrient rich conditions, but there were no apparent differences between them when fitness was determined by relative competitive ability. In addition, temperature affected the relative growth of haploids and diploids, with haploids growing proportionately faster at higher temperatures. Tetraploids performed very poorly under all conditions compared. Cell geometric parameters were not consistent predictors of fitness under the conditions measured.