PDF(Pubmed)
Abstract：
Recently, hypotheses regarding the evolutionary patterns of ribosomal genes in ant chromosomes have been under discussion. One of these hypotheses proposes a relationship between chromosomal location and the number of rDNA sites, suggesting that terminal locations facilitate the dispersion of rDNA clusters through ectopic recombination during meiosis, while intrachromosomal locations restrict them to a single chromosome pair. Another hypothesis suggests that the multiplication of rDNA sites could be associated with an increase in the chromosome number in Hymenoptera due to chromosomal fissions. In this study, we physically mapped rDNA sites in 15 new ant species and also reviewed data on rDNA available since the revision by Teixeira et al. (2021a). Our objectives were to investigate whether the new data confirm the relationship between chromosomal location and the number of rDNA sites, and whether the increase in the chromosome number is significant in the dispersion of rDNA clusters in ant karyotypes. Combining our new data with all information on ant cytogenetics published after 2021, 40 new species and nine new genera were assembled. Most species exhibited intrachromosomal rDNA sites on a single chromosome pair, while three species showed these genes in terminal regions of multiple chromosome pairs. On one hand, the hypothesis that the chromosomal location of rDNA clusters may facilitate the dispersion of rDNA sites in the ant genome, as previously discussed, was strengthened, but, on the other hand, the hypothesis of chromosomal fission as the main mechanism for dispersion of ribosomal genes in ants is likely to be refuted. Furthermore, in certain genera, the location of rDNA sites remained similar among the species studied, whereas in others, the distribution of these genes showed significant variation between species, suggesting a more dynamic chromosomal evolution.
摘要：
最近,关于蚂蚁染色体中核糖体基因进化模式的假设一直在讨论中。这些假设之一提出了染色体位置和rDNA位点数量之间的关系，表明末端位置通过减数分裂期间的异位重组促进rDNA簇的分散，而染色体内位置将它们限制为单个染色体对。另一个假设表明，由于染色体分裂，rDNA位点的增殖可能与膜翅目中染色体数量的增加有关。在这项研究中,我们在15个新的蚂蚁物种中对rDNA位点进行了物理映射，并回顾了自Teixeira等人修订以来可用的rDNA数据。（2021a）。我们的目标是调查新数据是否证实了染色体位置和rDNA位点数量之间的关系，以及染色体数目的增加是否显著影响蚂蚁核型rDNA簇的分散。将我们的新数据与2021年后发布的有关蚂蚁细胞遗传学的所有信息相结合，组装了40个新物种和9个新属。大多数物种在单个染色体对上表现出染色体内rDNA位点，而三个物种在多个染色体对的末端区域显示了这些基因。一方面,假设rDNA簇的染色体位置可能促进rDNA位点在蚂蚁基因组中的分散，如前所述，加强了，但是,另一方面,染色体裂变是核糖体基因在蚂蚁体内分散的主要机制的假说可能会被驳斥。此外，在某些属中，rDNA位点的位置在所研究的物种中保持相似，而在其他人中，这些基因的分布显示出物种之间的显著差异，表明染色体进化更加动态.
