Exceptionally high levels of recombination across the honey bee genome
Exceptionally high levels of recombination across the honey bee genome
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DOI：
10.1101/gr.5680406
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发表时间：
2006-11-01
期刊：
影响因子：
7
通讯作者：
Page, Robert E., Jr.
中科院分区：
文献类型：
--
作者：
Beye, Martin;Gattermeier, Irene;Page, Robert E., Jr.
利用蜜蜂基因组序列的第一稿和改进的遗传图谱来分析显示出比之前分析的高等真核生物基因组高10倍的重组水平(19 cM/Mb)的基因组。异常高的重组率分布在整个基因组中，但变化幅度为两个数量级。关于重组的染色体、序列和基因参数的分析表明，局部重组率与到端粒的距离、GC含量和低重组基因组所描述的简单重复数有关。重组率并不随染色体大小而降低。在蜜蜂基因组中，每对减数分裂平均有5.7个重组事件。这与范围广泛的分类群形成了鲜明的对比，这些分类群具有统一的重组频率，每对染色体约1.6。在染色体配对过程中，过量的重组活性并不支持重组在稳定同源染色体对中的机械作用。重组率与基因大小有关，这表明内含子在低重组区域较大，并可能提高这些区域的选择效率。在高重组基因组中存在极少数转座子和没有反转录转座子。我们为异常高的全基因组重组率提出了进化论解释。
The first draft of the honey bee genome sequence and improved genetic maps are utilized to analyze a genome displaying 10 times higher levels of recombination ( 19 cM/Mb) than previously analyzed genomes of higher eukaryotes. The exceptionally high recombination rate is distributed genome-wide, but varies by two orders of magnitude. Analysis of chromosome, sequence, and gene parameters with respect to recombination showed that local recombination rate is associated with distance to the telomere, GC content, and the number of simple repeats as described for low-recombining genomes. Recombination rate does not decrease with chromosome size. On average 5.7 recombination events per chromosome pair per meiosis are found in the honey bee genome. This contrasts with a wide range of taxa that have a uniform recombination frequency of about 1.6 per chromosome pair. The excess of recombination activity does not support a mechanistic role of recombination in stabilizing pairs of homologous chromosome during chromosome pairing. Recombination rate is associated with gene size, suggesting that introns are larger in regions of low recombination and may improve the efficacy of selection in these regions. Very few transposons and no retrotransposons are present in the high-recombining genome. We propose evolutionary explanations for the exceptionally high genome-wide recombination rate.