Symbiosis as an adaptive process and source of phenotypic complexity
Symbiosis as an adaptive process and source of phenotypic complexity
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DOI：
10.1073/pnas.0611659104
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发表时间：
2007-05-15
影响因子：
11.1
通讯作者：
Moran, Nancy A.
中科院分区：
文献类型：
--
作者：
Moran, Nancy A.
基因组学揭示，不同物种的遗传系统往往没有很好地隔离：在一个谱系中进化的基因和能力往往被另一个谱系稳定地获得。虽然物种间的直接基因转移在所有主要类群中都有发生，但在原核生物中发生的频率似乎远高于多细胞真核生物。将新基因并入受体基因组的替代方案是获得稳定的、可能可遗传的共生关联，从而享受互补代谢能力的益处。这类共生现象在动物中经常出现;例如，许多昆虫类群在其进化史早期获得的共生关系的基础上实现了多样化。由此产生的协会是非常复杂的，往往涉及专门的细胞类型和器官，发育机制，确保共生体之间的几代人之间的转移，以及控制共生体增殖和位置的机制。长期专性共生体的基因组经常经历不可逆的基因丢失和退化，即使宿主进化对它们的依赖。在某些情况下，动物基因组可能已经从共生体获得了基因，反映了线粒体和质体基因组的基因摄取。多个共生体通常共存于同一宿主中，导致几个遗传学上遥远的基因组之间的共适应。
Genomics has revealed that inheritance systems of separate species are often not well segregated: genes and capabilities that evolve in one lineage are often stably acquired by another lineage. Although direct gene transfer between species has occurred at some level in all major groups, it appears to be far more frequent in prokaryotes than in multicellular eukaryotes. An alternative to incorporating novel genes into a recipient genome is acquiring a stable, possibly heritable, symbiotic association and thus enjoying benefits of complementary metabolic capabilities. These kinds of symbioses have arisen frequently in animals; for example, many insect groups have diversified on the basis of symbiotic associations acquired early in their evolutionary histories. The resulting associations are highly complex, often involving specialized cell types and organs, developmental mechanisms that ensure transfer of symbionts between generations, and mechanisms for controlling symbiont proliferation and location. The genomes of longterm obligate symbionts often undergo irreversible gene loss and deterioration even as hosts evolve dependence on them. In some cases, animal genomes may have acquired genes from symbionts, mirroring the gene uptake from mitochondrial and plastid genomes. Multiple symbionts often coexist in the same host, resulting in coadaptation among several phylogenetically distant genomes.