Allopolyploidization Lays the Foundation for Evolution of Distinct Populations: Evidence From Analysis of Synthetic Arabidopsis Allohexaploids
Allopolyploidization Lays the Foundation for Evolution of Distinct Populations: Evidence From Analysis of Synthetic Arabidopsis Allohexaploids
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DOI：
10.1534/genetics.112.139295
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发表时间：
2012-06-01
期刊：
影响因子：
3.3
通讯作者：
Madlung, Andreas
中科院分区：
文献类型：
--
作者：
Matsushita, Starr C.;Tyagi, Anand P.;Madlung, Andreas
多倍化是将多样性引入种群并促进进化变化的重要机制。大多数被子植物在其进化史上都经历过全基因组复制，导致基因组结构、基因调控和染色体维持的变化。以前的研究表明，多倍体可以符合减数分裂异常和体细胞遗传学镶嵌在拟南芥异源四倍体，但目前还不清楚这种现象是否可以有助于新的多样性或作为一种机制的物种形成。在这项研究中，我们测试的假设，镶嵌非整倍体有助于形成初期的多样性在新异源多倍体。我们产生了一个人口的合成拟南芥异源六倍体，并监测核型和表型变异，在这个人口的前七代。我们发现了同胞线特定的染色体数目的变化和迅速分化的表型之间的线，包括开花时间，叶片形状和花粉活力的证据。染色体组型在兄弟系之间和相同组织内的细胞之间变化。与异源四倍体不同，细胞型变异与表型新奇相关，至少在前七代仍然是一个主要的基因组不稳定因素。虽然目前还不清楚是否会出现新的稳定的非整倍体系从这些人口，我们的数据是一致的概念，体细胞非整倍性，特别是在较高水平的异源多倍体，可以作为一个进化相关的机制，以诱导快速变化，不仅在最初的异源多倍体化过程中，但也为随后的几代。这一过程可能为多个新物种奠定遗传基础，而不仅仅是一个新物种。
Polyploidization is an important mechanism for introducing diversity into a population and promoting evolutionary change. It is believed that most, if not all, angiosperms have undergone whole genome duplication events in their evolutionary history, which has led to changes in genome structure, gene regulation, and chromosome maintenance. Previous studies have shown that polyploidy can coincide with meiotic abnormalities and somatic cytogenetic mosaics in Arabidopsis allotetraploids, but it is unclear whether this phenomenon can contribute to novel diversity or act as a mechanism for speciation. In this study we tested the hypothesis that mosaic aneuploidy contributes to the formation of incipient diversity in neoallopolyploids. We generated a population of synthesized Arabidopsis allohexaploids and monitored karyotypic and phenotypic variation in this population over the first seven generations. We found evidence of sibling line-specific chromosome number variations and rapidly diverging phenotypes between lines, including flowering time, leaf shape, and pollen viability. Karyotypes varied between sibling lines and between cells within the same tissues. Cytotypic variation correlates with phenotypic novelty, and, unlike in allotetraploids, remains a major genomic destabilizing factor for at least the first seven generations. While it is still unclear whether new stable aneuploid lines will arise from these populations, our data are consistent with the notion that somatic aneuploidy, especially in higher level allopolyploids, can act as an evolutionary relevant mechanism to induce rapid variation not only during the initial allopolyploidization process but also for several subsequent generations. This process may lay the genetic foundation for multiple, rather than just a single, new species.