Dynamic evolution of megasatellites in yeasts.
Dynamic evolution of megasatellites in yeasts.
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DOI：
10.1093/nar/gkq207
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发表时间：
2010-08
影响因子：
14.9
通讯作者：
Richard GF
中科院分区：
文献类型：
--
作者：
Rolland T;Dujon B;Richard GF
大卫星是一个新的长串联重复家族，最近在酵母光滑念珠菌中发现。与较短的串联重复序列（例如小卫星）相比，大卫星基序的大小范围从 135 到超过 300 bp，并且允许计算各个基序之间的进化距离。利用基于相似基序之间核苷酸替换的分歧，我们确定了两个基序之间的最小距离，从而允许它们随后进行聚类。属于同一簇的基序经常出现在位于不同染色体上的不同大卫星中，这表明大卫星之间遗传信息的转移。相比之下，酿酒酵母FLO基因中少数相似串联重复序列的进化主要涉及亚端粒同源重组。我们估计了作用于大卫星基序及其宿主基因的选择性约束，并发现基序处于强纯化选择之下。令人惊讶的是，插入假基因中的基序也处于纯化选择之下，而假基因本身则中性进化。我们提出，巨卫星基序通过三种不同分子机制的组合进行传播：（i）基因复制，（ii）异位同源重组和（iii）基序从一个巨卫星转移到另一个巨卫星。这些机制积极合作创建新的巨型卫星，这些卫星可能在光滑念珠菌适应人类宿主的过程中发挥重要作用。
Megasatellites are a new family of long tandem repeats, recently discovered in the yeast Candida glabrata. Compared to shorter tandem repeats, such as minisatellites, megasatellite motifs range in size from 135 to more than 300 bp, and allow calculation of evolutionary distances between individual motifs. Using divergence based on nucleotide substitutions among similar motifs, we determined the smallest distance between two motifs, allowing their subsequent clustering. Motifs belonging to the same cluster are recurrently found in different megasatellites located on different chromosomes, showing transfer of genetic information between megasatellites. In comparison, evolution of the few similar tandem repeats in Saccharomyces cerevisiae FLO genes mainly involves subtelomeric homologous recombination. We estimated selective constraints acting on megasatellite motifs and their host genes, and found that motifs are under strong purifying selection. Surprisingly, motifs inserted within pseudogenes are also under purifying selection, whereas the pseudogenes themselves evolve neutrally. We propose that megasatellite motifs propagate by a combination of three different molecular mechanisms: (i) gene duplication, (ii) ectopic homologous recombination and (iii) transfer of motifs from one megasatellite to another one. These mechanisms actively cooperate to create new megasatellites, that may play an important role in the adaptation of Candida glabrata to its human host.
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影响因子：
30.8
作者：
Verstrepen, KJ;Jansen, A;Fink, GR
通讯作者：
Fink, GR
影响因子：
10.7
作者：
TAMURA, K;NEI, M
通讯作者：
NEI, M
影响因子：
4.4
作者：
Haber, JE;Louis, EJ
通讯作者：
Louis, EJ
影响因子：
5.3
作者：
Pâques, F;Leung, WY;Haber, JE
通讯作者：
Haber, JE
影响因子：
14.9
作者：
Chenna, R;Sugawara, H;Thompson, JD
通讯作者：
Thompson, JD