Complex adaptations can drive the evolution of the capacitor [PSI], even with realistic rates of yeast sex.
Complex adaptations can drive the evolution of the capacitor [PSI], even with realistic rates of yeast sex.
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DOI：
10.1371/journal.pgen.1000517
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发表时间：
2009-06
期刊：
影响因子：
4.5
通讯作者：
Masel J
中科院分区：
文献类型：
--
作者：
Griswold CK;Masel J
[PSI+]Prion可能通过揭示以前神秘的遗传变异来增强进化性，但目前尚不清楚这种进化性属性是否会受到自然选择的青睐。性别抑制了其他假定的进化机制的进化，例如突变等位基因。这篇论文探讨了性别是否也阻止了自然选择有利于[PSI+]形成的修饰性等位基因。性行为可能允许“骗子”等位基因的传播，这些等位基因通过交配获得[PSI+]的好处，而不会在不适应的时候产生[PSI+]的成本。利用最近对矛盾酵母性别频率的定量估计，我们计算出，只要酵母种群偶尔需要涉及两个座位之间协同上位的复杂适应，为了进化而进行的自然选择可以推动[PSI+]系统的进化。如果适应总是很简单，只需要在一个座位上进行替换，那么[PSI+]系统就不受自然选择的青睐。专性交配可能会抑制其他物种中类似[PSI+]系统的进化。可进化性可以进化吗？一种明显的更快进化的方法是通过突变等位基因来增加突变率。不幸的是，重组会迅速将变种人的等位基因从它创造的有利等位基因中分离出来。因此，突变者从促进适应中获得的好处很少，而且被认为不会在有性有机体中进化。在这里，我们发现[PSI+]Prion，不同于突变等位基因，将进化以促进有性酵母物种的进化。结合以前对[PSI+]介导的适应的实验室研究，以及与[PSI+]介导的野外适应一致的生物信息学研究，我们的理论结果牢固地确立了[PSI+]作为进化进化的模型系统。我们还阐明了涉及多个基因的复杂适应的重要性。涉及多个同时基因的适应推动了该系统的进化性进化。这项工作是一个重要的原则证明，表明进化性有时可以在现实条件下进化。
The [PSI+] prion may enhance evolvability by revealing previously cryptic genetic variation, but it is unclear whether such evolvability properties could be favored by natural selection. Sex inhibits the evolution of other putative evolvability mechanisms, such as mutator alleles. This paper explores whether sex also prevents natural selection from favoring modifier alleles that facilitate [PSI+] formation. Sex may permit the spread of “cheater” alleles that acquire the benefits of [PSI+] through mating without incurring the cost of producing [PSI+] at times when it is not adaptive. Using recent quantitative estimates of the frequency of sex in Saccharomyces paradoxus, we calculate that natural selection for evolvability can drive the evolution of the [PSI+] system, so long as yeast populations occasionally require complex adaptations involving synergistic epistasis between two loci. If adaptations are always simple and require substitution at only a single locus, then the [PSI+] system is not favored by natural selection. Obligate sex might inhibit the evolution of [PSI+]-like systems in other species. Can evolvability evolve? One obvious way to evolve faster is via mutator alleles that increase the mutation rate. Unfortunately, recombination will rapidly separate a mutator allele from the advantageous alleles that it creates. Mutators, therefore, gain very little benefit from promoting adaptations and are thought not to evolve in sexual organisms. Here we find that the [PSI+] prion, unlike mutator alleles, will evolve to promote evolvability in sexual yeast species. Together with previous laboratory studies of [PSI+]–mediated adaptation, and with bioinformatic studies consistent with [PSI+]–mediated adaptation in the wild, our theoretical results firmly establish [PSI+] as a model system for the evolution of evolvability. We also shed light on the importance of complex adaptations involving multiple genes. Adaptations involving multiple simultaneous genes drive the evolution of evolvability in this system. This work is an important proof of principle, showing that evolvability can sometimes evolve under realistic conditions.
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影响因子：
3.3
作者：
Kim, Yuseob
通讯作者：
Kim, Yuseob
影响因子：
9.2
作者：
Brookfield, JFY
通讯作者：
Brookfield, JFY
影响因子：
3.3
作者：
Masel, J
通讯作者：
Masel, J
DOI：
10.1073/pnas.0504882102
发表时间：
2005-07-26
影响因子：
11.1
作者：
Nakayashiki, T;Kurtzman, CP;Wickner, RB
通讯作者：
Wickner, RB
影响因子：
11.4
作者：
Pál, C
通讯作者：
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