Cryptic fitness advantage: diploids invade haploid populations despite lacking any apparent advantage as measured by standard fitness assays.
Cryptic fitness advantage: diploids invade haploid populations despite lacking any apparent advantage as measured by standard fitness assays.
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DOI：
10.1371/journal.pone.0026599
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发表时间：
2011
期刊：
影响因子：
3.7
通讯作者：
Otto SP
中科院分区：
文献类型：
--
作者：
Gerstein AC;Otto SP
倍性在物种内部和物种之间存在巨大差异，但影响倍性变体何时或为何具有适应性的因素仍然知之甚少。我们之前的工作发现，二倍体个体在酿酒酵母的 10 个复制单倍体群体中反复出现，并且在每一种情况下，我们都在实验室分批培养进化的 1800 个无性世代中亲眼目睹了二倍体的接管。导致二倍体在单倍体种群中频率上升的特征仍然未知。在这里，我们提出了一些实验，目的是确定这个特征（或多个特征）可能是什么。实验既通过在原始实验期间每两周（93代）从冷冻库存中取样少量菌落来进行，也通过在倍性多态性最普遍的两个时间点取样大量菌落来进行。令人惊讶的是，我们的适应性成分测量（滞后期、生长速率、生物量产量）均未表明二倍体具有优势。类似地，针对共同竞争者的竞争测定以及从同一时间点分离的单倍体和二倍体集落之间的直接竞争未能表明二倍体优势。此外，我们发现相同倍性水平的菌落之间存在大量性状变异。只有后来出现的二倍体才表现出优于单倍体的竞争优势，这表明最终接管的适应性优势并不是二倍体本身，而是二倍体谱系子集的属性。然而，二倍体最初上升到中频不能用任何所使用的适应性措施来解释；我们建议解决这个谜团的是负频率依赖选择，在使用的标准适应度测量中忽略了这一点。
Ploidy varies tremendously within and between species, yet the factors that influence when or why ploidy variants are adaptive remains poorly understood. Our previous work found that diploid individuals repeatedly arose within ten replicate haploid populations of Saccharomyces cerevisiae, and in each case we witnessed diploid takeover within 1800 asexual generations of batch culture evolution in the lab. The character that allowed diploids to rise in frequency within haploid populations remains unknown. Here we present a number of experiments conducted with the goal to determine what this trait (or traits) might have been. Experiments were conducted both by sampling a small number of colonies from the stocks frozen every two weeks (93 generations) during the original experiment, as well through sampling a larger number of colonies at the two time points where polymorphism for ploidy was most prevalent. Surprisingly, none of our fitness component measures (lag phase, growth rate, biomass production) indicated an advantage to diploidy. Similarly, competition assays against a common competitor and direct competition between haploid and diploid colonies isolated from the same time point failed to indicate a diploid advantage. Furthermore, we uncovered a tremendous amount of trait variation among colonies of the same ploidy level. Only late-appearing diploids showed a competitive advantage over haploids, indicating that the fitness advantage that allowed eventual takeover was not diploidy per se but an attribute of a subset of diploid lineages. Nevertheless, the initial rise in diploids to intermediate frequency cannot be explained by any of the fitness measures used; we suggest that the resolution to this mystery is negative frequency-dependent selection, which is ignored in the standard fitness measures used.
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影响因子：
4.5
作者：
Gerstein AC;Chun HJ;Grant A;Otto SP
通讯作者：
Otto SP
DOI：
10.1098/rspb.1979.0086
发表时间：
1979-01-01
期刊：
PROCEEDINGS OF THE ROYAL SOCIETY SERIES B-BIOLOGICAL SCIENCES
影响因子：
--
作者：
GOULD, SJ;LEWONTIN, RC
通讯作者：
LEWONTIN, RC
影响因子：
3.3
作者：
Hall, David W.;Joseph, Sarah B.
通讯作者：
Joseph, Sarah B.
影响因子：
2.1
作者：
Mable, BK
通讯作者：
Mable, BK
影响因子：
3.4
作者：
de Visser, J. Arjan G. M.;Lenski, Richard E.
通讯作者：
Lenski, Richard E.