Di-Nizo Camilla Bruno, Ferguson-Smith Malcolm Andrew, Silva Maria José de J
Instituto Butantan, Laboratório de Ecologia e Evolução, São Paulo, SP, Brazil.
Cambridge Resource Centre for Comparative Genomics, Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom.
Genet Mol Biol. 2020 Nov 13;43(4):e20200149. doi: 10.1590/1678-4685-GMB-2020-0149. eCollection 2020.
Rodents of the genus Cerradomys belong to the tribe Oryzomyini and present high chromosome variability with diploid numbers ranging from 2n=46 to 60. Classical cytogenetics and fluorescence in situ hybridization (FISH) with telomeric and whole chromosome-specific probes of another Oryzomyini, Oligoryzomys moojeni (OMO), were used to assess the karyotype evolution of the genus. Results were integrated into a molecular phylogeny to infer the hypothetical direction of chromosome changes. The telomeric FISH showed signals in telomeres in species that diverged early in the phylogeny, plus interstitial telomeric signals (ITS) in some species from the most derived clades (C. langguthi, C. vivoi, C. goytaca, and C. subflavus). Chromosome painting revealed homology from 23 segments of C. maracajuensis and C. marinhus to 32 of C. vivoi. Extensive chromosome reorganization was responsible for karyotypic differences in closely related species. Major drivers for genomic reshuffling were in tandem and centric fusion, fission, paracentric and pericentric inversions or centromere repositioning. Chromosome evolution was associated with an increase and decrease in diploid number in different lineages and ITS indicate remnants of ancient telomeres. Cytogenetics results corroborates that C. goytaca is not a junior synonym of C. subflavus since the karyotypic differences found may lead to reproductive isolation.
塞拉多鼠属（Cerradomys）的啮齿动物属于稻鼠族（Oryzomyini），其染色体变异性高，二倍体数范围为2n = 46至60。利用经典细胞遗传学以及用另一种稻鼠族动物莫氏稻鼠（Oligoryzomys moojeni，OMO）的端粒和全染色体特异性探针进行的荧光原位杂交（FISH），来评估该属的核型进化。研究结果被整合到分子系统发育中，以推断染色体变化的假设方向。端粒FISH在系统发育早期分化的物种的端粒中显示出信号，并且在一些来自最衍生分支（朗氏塞拉多鼠（C. langguthi）、维氏塞拉多鼠（C. vivoi）、戈氏塞拉多鼠（C. goytaca）和淡黄塞拉多鼠（C. subflavus））的物种中显示出间质端粒信号（ITS）。染色体涂染揭示了马拉卡茹塞拉多鼠（C. maracajuensis）和马林塞拉多鼠（C. marinhus）的23个片段与维氏塞拉多鼠的32个片段具有同源性。广泛的染色体重组导致了近缘物种的核型差异。基因组重排的主要驱动因素是串联和着丝粒融合、裂变、臂间和臂内倒位或着丝粒重新定位。染色体进化与不同谱系中二倍体数的增加和减少相关，并且ITS表明存在古老端粒的残余。细胞遗传学结果证实，戈氏塞拉多鼠不是淡黄塞拉多鼠的次异名，因为所发现的核型差异可能导致生殖隔离。
