PDF(Pubmed)
Abstract：
Recombination is responsible for breaking up haplotypes, influencing genetic variability, and the efficacy of selection. Bird genomes lack the protein PR domain-containing protein 9, a key determinant of recombination dynamics in most metazoans. Historical recombination maps in birds show an apparent stasis in positioning recombination events. This highly conserved recombination pattern over long timescales may constrain the evolution of recombination in birds. At the same time, extensive variation in recombination rate is observed across the genome and between different species of birds. Here, we characterize the fine-scale historical recombination map of an iconic migratory songbird, the Eurasian blackcap (Sylvia atricapilla), using a linkage disequilibrium-based approach that accounts for population demography. Our results reveal variable recombination rates among and within chromosomes, which associate positively with nucleotide diversity and GC content and negatively with chromosome size. Recombination rates increased significantly at regulatory regions but not necessarily at gene bodies. CpG islands are associated strongly with recombination rates, though their specific position and local DNA methylation patterns likely influence this relationship. The association with retrotransposons varied according to specific family and location. Our results also provide evidence of heterogeneous intrachromosomal conservation of recombination maps between the blackcap and its closest sister taxon, the garden warbler. These findings highlight the considerable variability of recombination rates at different scales and the role of specific genomic features in shaping this variation. This study opens the possibility of further investigating the impact of recombination on specific population-genomic features.
摘要：
重组负责分解单倍型，影响遗传变异，以及选择的功效。鸟类基因组缺乏含有蛋白质PR结构域的蛋白质9，这是大多数后生动物重组动力学的关键决定因素。鸟类的历史重组图显示，在定位重组事件方面存在明显的停滞。这种在长时间尺度上高度保守的重组模式可能会限制鸟类重组的进化。同时,在整个基因组和不同鸟类之间观察到重组率的广泛差异。这里,我们描述了标志性的迁徙鸣鸟的精细比例历史重组图，欧亚黑帽（Sylviaatricapilla），使用基于连锁不平衡的方法来解释人口统计。我们的结果揭示了染色体之间和内部的可变重组率，与核苷酸多样性和GC含量呈正相关，与染色体大小呈负相关。重组率在调控区显着增加，但不一定在基因体增加。CpG岛与重组率密切相关，尽管它们的特定位置和局部DNA甲基化模式可能会影响这种关系。与反转录转座子的关联根据特定的家族和位置而变化。我们的结果还提供了黑帽与其最接近的姐妹分类单元之间重组图的异质性染色体内保守性的证据，花园莺.这些发现强调了不同规模的重组率的相当大的变异性以及特定基因组特征在塑造这种变异中的作用。这项研究为进一步研究重组对特定群体基因组特征的影响提供了可能性。
