Everitt Turid, Rönneburg Tilman, Elsner Daniel, Olsson Anna, Liu Yuanzhen, Larva Tuuli, Korb Judith, Webster Matthew T
Medical Biochemistry and Microbiology, Uppsala University, 751 23 Uppsala, Sweden.
Evolutionary Biology and Ecology, University of Freiburg, D-79104 Freiburg, Germany.
Genome Res. 2025 May 2;35(5):1124-1137. doi: 10.1101/gr.279180.124.
Meiotic recombination is a fundamental evolutionary process that facilitates adaptation and the removal of deleterious genetic variation. Social Hymenoptera exhibit some of the highest recombination rates among metazoans, whereas high recombination rates have not been found among nonsocial species from this insect order. It is unknown whether elevated recombination rates are a ubiquitous feature of all social insects. In many metazoan taxa, recombination is mainly restricted to hotspots a few kilobases in length. However, little is known about the prevalence of recombination hotspots in insect genomes. Here we infer recombination rate and its fine-scale variation across the genomes of two social species from the insect order Blattodea: the termites and We used linkage disequilibrium-based methods to infer recombination rate. We infer that recombination rates are close to 1 cM/Mb in both species, similar to the average metazoan rate. We also observe a highly punctate distribution of recombination in both termite genomes, indicative of the presence of recombination hotspots. We infer the presence of full-length genes in the genomes of both species, which suggests recombination hotspots in termites might be determined by , as they are in mammals. We also find that recombination rates in genes are correlated with inferred levels of germline DNA methylation. The finding of low recombination rates in termites indicates that eusociality is not universally connected to elevated recombination rate. We speculate that the elevated recombination rates in social Hymenoptera are instead promoted by intense selection among haploid males.
减数分裂重组是一个基本的进化过程，它有助于适应和消除有害的遗传变异。社会性膜翅目昆虫在后生动物中表现出一些最高的重组率，而在该昆虫目的非社会性物种中尚未发现高重组率。尚不清楚重组率升高是否是所有社会性昆虫的普遍特征。在许多后生动物类群中，重组主要局限于长度为几千碱基的热点区域。然而，关于昆虫基因组中重组热点的普遍性知之甚少。在这里，我们推断了来自蜚蠊目的两种社会性昆虫基因组的重组率及其精细尺度的变异：白蚁 和 。我们使用基于连锁不平衡的方法来推断重组率。我们推断这两个物种的重组率都接近1厘摩/兆碱基，与后生动物的平均速率相似。我们还观察到两种白蚁基因组中的重组分布都高度分散，这表明存在重组热点。我们推断这两个物种的基因组中都存在全长 基因，这表明白蚁中的重组热点可能像在哺乳动物中一样，由 决定。我们还发现基因中的重组率与推断的生殖系DNA甲基化水平相关。白蚁中重组率低的发现表明，真社会性并非普遍与重组率升高相关。我们推测，社会性膜翅目昆虫中重组率升高反而受到单倍体雄性之间强烈选择的促进。
