Meta‐analysis of chromosome‐scale crossover rate variation in eukaryotes and its significance to evolutionary genomics

Understanding the distribution of crossovers along chromosomes is crucial to evolutionary genomics because the crossover rate determines how strongly a genome region is influenced by natural selection. Nevertheless, generalities in the chromosome-scale distribution of crossovers have not been investigated formally. We fill this gap by synthesizing joint information on genetic and physical maps across 62 animal, plant, and fungal species. Our quantitative analysis reveals a strong and taxonomically wide-spread reduction of the crossover rate in the center of chromosomes relative to their peripheries. We demonstrate that this pattern is poorly explained by the position of the centromere, but find that the magnitude of the relative reduction in the crossover rate in chromosome centers increases with chromosome length. That is, long chromosomes often display a dramatically low crossover rate in their center whereas short chromosomes exhibit a relatively homogeneous crossover rate. This obse...解析染色体沿线交叉互换（crossover）的分布模式，对进化基因组学研究至关重要，因为交叉互换率直接决定了基因组区域受自然选择作用的强度。然而，学界尚未针对染色体尺度下交叉互换分布的通用规律开展正式的系统性研究。本研究通过整合62种动物、植物与真菌的遗传图谱与物理图谱联合数据，填补了这一研究空白。我们的定量分析结果显示，相较于染色体外周区域，染色体中部的交叉互换率存在显著降低的现象，且这一规律在多个分类群中广泛存在。研究表明，该分布模式难以通过着丝粒（centromere）的位置加以解释，但我们发现，染色体中部交叉互换率的相对降低幅度随染色体长度的增加而增大：换言之，长染色体的中部往往呈现出极低的交叉互换率，而短染色体的交叉互换率则相对均匀一致。这一观测