Recombination drives the evolution of GC-content in the human genome
Recombination drives the evolution of GC-content in the human genome
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DOI：
10.1093/molbev/msh070
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发表时间：
2004-06-01
影响因子：
10.7
通讯作者：
Duret, L
中科院分区：
文献类型：
--
作者：
Meunier, J;Duret, L
揭示导致类群之间或基因组中性取代模式变化的进化力量是识别功能序列特征的一个主要问题。哺乳动物基因组显示出 GC 含量（等容线）的大规模区域差异，但对该结构起源的替代过程知之甚少。我们分析了 14.3 Mb 灵长类非编码区的中性取代模式。我们表明，序列进化的GC含量与交叉率（特别是在雌性中）密切相关（r(2) = 0.16，P小于或等于2 10(-16)）。这表明重组驱动了人类碱基组成的进化（可能通过有偏差的基因转换过程）。目前的取代模式与过去非常不同，导致我们基因组的等容线结构发生重大改变。这种非平衡情况表明，重组率的变化在进化过程中相对频繁地发生，可能是核型重排的结果。这些结果对于理解多种有性生物中替代过程的空间和时间变化以及检测 DNA 序列中自然选择的标志具有重要意义。
Unraveling the evolutionary forces responsible for variations of neutral substitution patterns among taxa or along genomes is a major issue in the identification of functional sequence features. Mammalian genomes show large-scale regional variations of GC-content (the isochores), but the substitution processes at the origin of this structure are poorly understood. We have analyzed the pattern of neutral substitutions in 14.3 Mb of primate noncoding regions. We show that the GC-content toward which sequences are evolving is strongly correlated (r(2) = 0.16, P less than or equal to 2 10(-16)) with the rate of crossovers (notably in females). This demonstrates that recombination drives the evolution of base composition in human (probably via the process of biased gene conversion). The present substitution patterns are very different from what they had been in the past, resulting in a major modification of the isochore structure of our genome. This non-equilibrium situation suggests that changes of recombination rates occur relatively frequently during evolution, possibly as a consequence of karyotype rearrangements. These results have important implications for understanding the spatial and temporal variations of substitution processes in a broad range of sexual organisms, and for detecting the hallmarks of natural selection in DNA sequences.