Arias-Sardá Cristina, Quigley Sarah, Farré Marta
School of Biosciences, University of Kent, Canterbury, UK.
Mol Ecol. 2024 Dec;33(24):e17197. doi: 10.1111/mec.17197. Epub 2023 Nov 8.
Studying when and where gross genomic rearrangements occurred during evolution is key to understanding changes in genome structure with functional consequences that might eventually lead to speciation. Here we identified chromosome rearrangements in ruminants, a clade characterized by large chromosome differences. Using 26 genome assemblies, we reconstructed five ancestral karyotypes and classified the rearrangement events occurring in each lineage. With these reconstructions, we then identified evolutionary breakpoints regions (EBRs) and synteny fragments. Ruminant karyotype evolution is characterized by inversions, while interchromosomal rearrangements occurred preferentially in the oldest ancestor of ruminants. We found that EBRs are depleted of protein coding genes, including housekeeping genes. Similarly, EBRs are not enriched in high GC regions, suggesting that meiotic double strand breaks might not be their origin. Overall, our results characterize at fine detail the location of chromosome rearrangements in ruminant evolution and provide new insights into the formation of EBRs.
研究在进化过程中基因组重排发生的时间和地点，是理解基因组结构变化及其功能后果（最终可能导致物种形成）的关键。在这里，我们鉴定了反刍动物中的染色体重排，反刍动物是一个以巨大染色体差异为特征的进化枝。利用26个基因组组装数据，我们重建了五种祖先核型，并对每个谱系中发生的重排事件进行了分类。通过这些重建，我们随后鉴定了进化断点区域（EBRs）和同线片段。反刍动物核型进化的特征是倒位，而染色体间重排优先发生在反刍动物最古老的祖先中。我们发现EBRs中缺乏蛋白质编码基因，包括管家基因。同样，EBRs在高GC区域也不富集，这表明减数分裂双链断裂可能不是其起源。总体而言，我们的结果详细描述了反刍动物进化中染色体重排的位置，并为EBRs的形成提供了新的见解。
