Profuse evolutionary diversification and speciation on volcanic islands: transposon instability and amplification bursts explain the genetic paradox.
Profuse evolutionary diversification and speciation on volcanic islands: transposon instability and amplification bursts explain the genetic paradox.
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DOI：
10.1186/s13062-016-0146-1
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发表时间：
2016-09-06
期刊：
影响因子：
5.5
通讯作者：
Craddock EM
中科院分区：
文献类型：
--
作者：
Craddock EM
稀有动植物殖民者产生的物种丰富的适应性辐射在偏远的火山群岛上很常见。然而，他们提出了一个悖论。奠基事件的严重遗传瓶颈和近亲繁殖衰退的影响，再加上固有的火山环境压力，似乎预示着进化潜力的降低和灭绝风险的增加，而不是快速的适应性分化和物种形成。值得注意的是，真核生物基因组包含许多转座因子家族（te），这些转座因子家族可以被基因组冲击动员起来；这些因素可能是火山岛上基因重组和物种形成的主要驱动因素。在这里，我提出，夏威夷和其他海洋岛屿上特有的夏威夷果蝇和其他陆地谱系的壮观辐射和多样化的一个中心因素是由火山栖息地独特的生态特征引起的多个te的反复转换。由于生物和非生物因素，偏远火山岛上的创始人和种群经历了显著水平的生理和基因组压力。这导致te通常的表观遗传抑制被破坏，释放它们增殖和传播，这反过来又产生了新的遗传变异和重塑基因组调控回路，促进了快速的形态、生态和行为变化，以及适应性辐射。为了获得对这一假设的经验支持，测试生物应该暴露在长时间的热应激、高水平的二氧化碳和其他火山气体中，并进行近亲繁殖。随后的全基因组测序和TE数量和位置的生物信息学筛选数据将与测试菌株的初始暴露前TE信息进行比较，这是一个劳动密集型项目。讨论了由该假设产生的几种预测结果。目前可用的数据与提出的应力诱导TE动员作为火山岛进化多样化和物种形成的触发因素的概念一致。其主要含义是，te和物种在火山岛上的繁殖速度应该比其他地方要快得多。其次，一个谱系的可进化性可能与te在基因组中的丰度和分布有关。具有高te基因组比例的火山栖息地的成功殖民者可能最容易找到一个物种谱系，从而产生戏剧性的适应性辐射。在TEs中失去活力的殖民者很可能在进化上受到限制，即使有，也很少多样化。本文由James Shapiro博士和Wolfgang Miller博士（由编委会成员I. King Jordan博士提名）审阅。
Species-rich adaptive radiations arising from rare plant and animal colonizers are common on remote volcanic archipelagoes. However, they present a paradox. The severe genetic bottleneck of founder events and effects of inbreeding depression, coupled with the inherently stressful volcanic environment, would seem to predict reduced evolutionary potential and increased risk of extinction, rather than rapid adaptive divergence and speciation. Significantly, eukaryotic genomes harbor many families of transposable elements (TEs) that are mobilized by genome shock; these elements may be the primary drivers of genetic reorganization and speciation on volcanic islands. Here I propose that a central factor in the spectacular radiation and diversification of the endemic Hawaiian Drosophila and other terrestrial lineages on the Hawaiian and other oceanic islands has been repeated bursts of transposition of multiple TEs induced by the unique ecological features of volcanic habitats. Founder individuals and populations on remote volcanic islands experience significant levels of physiological and genomic stress as a consequence of both biotic and abiotic factors. This results in disruption of the usual epigenetic suppression of TEs, unleashing them to proliferate and spread, which in turn gives rise to novel genetic variation and remodels genomic regulatory circuits, facilitating rapid morphological, ecological and behavioral change, and adaptive radiation. To obtain empirical support for the hypothesis, test organisms should be exposed to prolonged heat stress, high levels of carbon dioxide and other volcanic gases, along with inbreeding. Data from subsequent whole genome sequencing and bioinformatics screening for TE numbers and locations would then be compared with initial pre-exposure TE information for the test strains, a labor-intensive project. Several predicted outcomes arising from the hypothesis are discussed. Currently available data are consistent with the proposed concept of stress-induced TE mobilization as a trigger of evolutionary diversification and speciation on volcanic islands. The main implication is that both TEs and species should proliferate at a much higher rate on volcanic islands than elsewhere. Second, the evolvability of a lineage may correlate with the abundance and distribution of TEs in the genome. Successful colonizers of volcanic habitats with high genomic proportions of TEs may be best poised to found a speciose lineage that gives rise to a dramatic adaptive radiation. Colonizers that are depauperate in TEs are likely to be evolutionarily constrained and diversify little, if at all. This article was reviewed by Dr. James Shapiro and Dr. Wolfgang Miller (nominated by Editorial Board member Dr. I. King Jordan).
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影响因子：
2.1
作者：
Chen, B.;Walser, J.-C.;Feder, M. E.
通讯作者：
Feder, M. E.
DOI：
10.1016/j.cbpb.2005.01.019
发表时间：
2005-03-01
影响因子：
2.3
作者：
Badre, NH;Martin, ME;Cooper, RL
通讯作者：
Cooper, RL
DOI：
10.1073/pnas.95.16.9402
发表时间：
1998-08-04
影响因子：
11.1
作者：
Baldwin, BG;Sanderson, MJ
通讯作者：
Sanderson, MJ
DOI：
10.1073/pnas.87.18.7055
发表时间：
1990-09-01
影响因子：
11.1
作者：
CARSON, HL;LOCKWOOD, JP;CRADDOCK, EM
通讯作者：
CRADDOCK, EM
影响因子：
64.8
作者：
Biemont, Christian;Vieira, Cristina
通讯作者：
Vieira, Cristina