Chromosomal inversions are among the primary drivers of genome structure evolution in a wide range of natural populations. Although there is an impressive array of theory and empirical analyses that have identified conditions under which inversions can be positively selected, comparatively little data are available on the fitness impacts of these genome structural rearrangements themselves. Because inversion breakpoints can disrupt functional elements and alter chromatin domains, the precise positioning of an inversion’s breakpoints can strongly affect its fitness. Here, we compared the fine-scale distribution of low-frequency inversion breakpoints with those of high-frequency inversions and inversions that have gone to fixation between Drosophila species. We identified a number of differences among frequency classes that may influence inversion fitness. In particular, breakpoints that are proximal to insulator elements, generate large tandem duplications, and minimize impacts on gene coding spans which are more prevalent in high-frequency and fixed inversions than in rare inversions. The data suggest that natural selection acts to preserve both genes and larger cis-regulatory networks in the occurrence and spread of rearrangements. These factors may act to limit the availability of high-fitness arrangements when suppressed recombination is favorable.

中文翻译：

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细尺度位置效应塑造黑腹果蝇中反转断点的分布。

染色体倒位是各种自然种群中基因组结构进化的主要驱动因素之一。尽管有大量令人印象深刻的理论和经验分析确定了可以积极选择倒置的条件，但关于这些基因组结构重排本身的适应性影响的数据相对较少。由于反转断点会破坏功能元素并改变染色质域，因此反转断点的精确定位会强烈影响其适应性。在这里，我们比较了低频反转断点与高频反转和已在果蝇之间固定的反转断点的精细分布物种。我们确定了可能影响反转适应度的频率类别之间的许多差异。特别是，靠近绝缘体元件的断点会产生大量的串联重复，并将对基因编码跨度的影响最小化，这在高频和固定倒位中比在罕见倒位中更为普遍。数据表明，自然选择的作用是在重排的发生和传播中保护基因和更大的顺式调节网络。当抑制重组是有利的时，这些因素可能会限制高适应性安排的可用性。