SHORT INDELS ARE SUBJECT TO INSERTION-BIASED GENE CONVERSION
SHORT INDELS ARE SUBJECT TO INSERTION-BIASED GENE CONVERSION
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DOI：
10.1111/evo.12129
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发表时间：
2013-09-01
期刊：
影响因子：
3.3
通讯作者：
Bazykin, Georgii A.
中科院分区：
文献类型：
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作者：
Leushkin, Evgeny V.;Bazykin, Georgii A.
同源基因座之间的结合伴随着异源双链体的形成。修复异源双链中的错配通常会导致称为基因转换的过程中的单核苷酸取代。在不同的生物体中，基因转换被证明是GC偏向的;也就是说，在这个过程中，W（A或T）S（G或C）取代比SW取代更有可能。在这里，我们表明，短的非编码indel，达到固定物种之间的插入/缺失率与重组率在果蝇，智人，和酿酒酵母正相关。这种相关性是由于在高重组区域中插入的固定率增加和缺失的固定率降低。D.全基因组indel多态性和趋异性数据。melanogaster排除了突变偏好和选择是这种趋势的原因，指出插入偏好的基因转换是最可能的解释。单核苷酸indel的插入偏好最强，并随indel长度的增加而降低。在高重组率的区域，这种偏差导致固定的短插入超过缺失高达约5倍，并显著影响DNA片段的进化。
Recombination between homologous loci is accompanied by formation of heteroduplexes. Repairing mismatches in heteroduplexes often leads to single nucleotide substitutions in a process known as gene conversion. Gene conversion was shown to be GC-biased in different organisms; that is, a W(A or T)S(G or C) substitution is more likely in this process than a SW substitution. Here, we show that the insertion/deletion ratio for short noncoding indels that reach fixation between species is positively correlated with the recombination rate in Drosophila melanogaster, Homo sapiens, and Saccharomyces cerevisiae. This correlation is both due to an increase of the fixation rate of insertions and decrease of the fixation rate of deletions in regions of high recombination. Whole-genome data on indel polymorphism and divergence in D. melanogaster rule out mutation biases and selection as the cause of this trend, pointing to insertion-biased gene conversion as the most likely explanation. The bias toward insertions is the strongest for single-nucleotide indels, and decreases with indel length. In regions of high recombination rate this bias leads to an up to approximate to 5-fold excess of fixed short insertions over deletions, and substantially affects the evolution of DNA segments.