Extended genomes: symbiosis and evolution.
Extended genomes: symbiosis and evolution.
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扩展基因组：共生和进化。
DOI：
10.1098/rsfs.2017.0001
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发表时间：
2017-10-06
期刊：
影响因子：
4.4
通讯作者：
Hurst GDD
中科院分区：
文献类型：
--
作者：
Hurst GDD
个体生物学的许多方面源自其与共生微生物的相互作用，这进一步定义了宿主物种的生态和进化的许多方面。微生物在个体有机体功能中的中心地位催生了全生物体的概念——个体的生物学最好理解为“宿主有机体”和内部共生体的复合体。这个概念被进一步阐述，将全生物视为一个选择单位。在这篇综述中，我批判性地研究了将全生物视为选择单位是否有用。我认为微生物遗传——微生物从亲本到后代的直接传递——是决定全生物在多大程度上可以有效地被视为选择水平的关键因素。在直接垂直传播（VT）常见的情况下，微生物形成了扩展基因组的一部分，其动态可以用简单的群体遗传学进行建模，但与核基因的经典突变/选择模型有细微的定量区别。如果没有直接的 VT，微生物适应性和宿主个体适应性之间的相关性就会减弱，并且微生物适应性仅与宿主生存（而不是繁殖）相关。此外，宿主内微生物的更替可能会减少微生物适应性与宿主生存之间的关联，并且在多微生物群落中，微生物适应性可能很大程度上源自于战胜其他微生物、避免宿主免疫清除以及通过噬菌体感染将死亡率降至最低的能力。这些竞争性的选择压力使得全生物适应度成为决定共生体进化的一个非常次要的考虑因素。尽管如此，非遗传微生物在生物体功能中的重要性是毋庸置疑的，因此，引起宿主个体内部和之间微生物变异和进化的进化和生态过程代表了生物学的一个关键研究领域。
Many aspects of an individual's biology derive from its interaction with symbiotic microbes, which further define many aspects of the ecology and evolution of the host species. The centrality of microbes in the function of individual organisms has given rise to the concept of the holobiont—that an individual's biology is best understood as a composite of the ‘host organism’ and symbionts within. This concept has been further elaborated to posit the holobiont as a unit of selection. In this review, I critically examine whether it is useful to consider holobionts as a unit of selection. I argue that microbial heredity—the direct passage of microbes from parent to offspring—is a key factor determining the degree to which the holobiont can usefully be considered a level of selection. Where direct vertical transmission (VT) is common, microbes form part of extended genomes whose dynamics can be modelled with simple population genetics, but that nevertheless have subtle quantitative distinctions from the classic mutation/selection model for nuclear genes. Without direct VT, the correlation between microbial fitness and host individual fitness erodes, and microbe fitness becomes associated with host survival only (rather than reproduction). Furthermore, turnover of microbes within a host may lessen associations between microbial fitness with host survival, and in polymicrobial communities, microbial fitness may derive largely from the ability to outcompete other microbes, to avoid host immune clearance and to minimize mortality through phage infection. These competing selection pressures make holobiont fitness a very minor consideration in determining symbiont evolution. Nevertheless, the importance of non-heritable microbes in organismal function is undoubted—and as such the evolutionary and ecological processes giving rise to variation and evolution of the microbes within and between host individuals represent a key research area in biology.
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影响因子：
9.8
作者：
Brooks AW;Kohl KD;Brucker RM;van Opstal EJ;Bordenstein SR
通讯作者：
Bordenstein SR
影响因子：
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作者：
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影响因子：
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通讯作者：
Bork, Peer
DOI：
10.1073/pnas.1002601107
发表时间：
2010-06-29
影响因子：
11.1
作者：
Dominguez-Bello, Maria G.;Costello, Elizabeth K.;Knight, Rob
通讯作者：
Knight, Rob
影响因子：
9.8
作者：
Dunbar HE;Wilson AC;Ferguson NR;Moran NA
通讯作者：
Moran NA