Different selective pressures lead to different genomic outcomes as newly-formed hybrid yeasts evolve.
Different selective pressures lead to different genomic outcomes as newly-formed hybrid yeasts evolve.
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DOI：
10.1186/1471-2148-12-46
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发表时间：
2012-04-02
影响因子：
3.4
通讯作者：
Rosenzweig F
中科院分区：
文献类型：
--
作者：
Piotrowski JS;Nagarajan S;Kroll E;Stanbery A;Chiotti KE;Kruckeberg AL;Dunn B;Sherlock G;Rosenzweig F
种间杂交发生在每一个真核生物界。虽然杂交后代经常处于选择性劣势，但在某些情况下，它们增加的基因组大小和复杂性可能导致比它们的祖先更大的胁迫抗性，这在它们祖先范围的边缘可能是适应性有利的。虽然这一现象已被反复记录在外地，长期选择的杂交种群的反应并没有经常在实验室中进行探讨。为了填补这一知识空白，我们跨越了严格意义上的酵母菌群中两个关系最远的成员，S。酿酒酵母和酿酒酵母。uvarum，并建立了同倍体和非整倍体杂种的混合群体，以研究不同类型的选择如何影响杂种基因组结构。随着温度从31°C逐渐升高到46.5°C超过500代的连续培养，选择有利于S. uvarum基因组，尽管基因组丢失的动力学在独立的重复中不同。温度选择的菌株表现出更大的固有和诱导的耐热性比亲本物种和创始杂交种，也表现出耐乙醇性。相反，当外源乙醇从0%增加到14%超过500代的连续培养时，选择有利于整倍体S。酿酒酵母× S.葡萄囊杂种乙醇选择菌株比S. uvarum和一个创始杂交种，但没有表现出耐温度胁迫。相对于亲本和创始杂交种，温度选择的菌株表现出细胞壁结构的遗传差异，表现为对酶消化和米卡芬净（靶向细胞壁生物合成）的抗性增加。这是第一项实验研究表明，新形成的种间杂种的基因组命运取决于它们在进化过程中遇到的选择类型，强调了生态剧场在决定进化游戏结果方面的重要性。
Interspecific hybridization occurs in every eukaryotic kingdom. While hybrid progeny are frequently at a selective disadvantage, in some instances their increased genome size and complexity may result in greater stress resistance than their ancestors, which can be adaptively advantageous at the edges of their ancestors' ranges. While this phenomenon has been repeatedly documented in the field, the response of hybrid populations to long-term selection has not often been explored in the lab. To fill this knowledge gap we crossed the two most distantly related members of the Saccharomyces sensu stricto group, S. cerevisiae and S. uvarum, and established a mixed population of homoploid and aneuploid hybrids to study how different types of selection impact hybrid genome structure. As temperature was raised incrementally from 31°C to 46.5°C over 500 generations of continuous culture, selection favored loss of the S. uvarum genome, although the kinetics of genome loss differed among independent replicates. Temperature-selected isolates exhibited greater inherent and induced thermal tolerance than parental species and founding hybrids, and also exhibited ethanol resistance. In contrast, as exogenous ethanol was increased from 0% to 14% over 500 generations of continuous culture, selection favored euploid S. cerevisiae x S. uvarum hybrids. Ethanol-selected isolates were more ethanol tolerant than S. uvarum and one of the founding hybrids, but did not exhibit resistance to temperature stress. Relative to parental and founding hybrids, temperature-selected strains showed heritable differences in cell wall structure in the forms of increased resistance to zymolyase digestion and Micafungin, which targets cell wall biosynthesis. This is the first study to show experimentally that the genomic fate of newly-formed interspecific hybrids depends on the type of selection they encounter during the course of evolution, underscoring the importance of the ecological theatre in determining the outcome of the evolutionary play.
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影响因子：
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作者：
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