Laboratório de Citogenética de Peixes, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP 13565-905, Brazil.
Secretaria de Estado de Educação de Mato Grosso-SEDUC-MT, Cuiabá, MT 78049-909, Brazil.
Int J Mol Sci. 2019 Jun 16;20(12):2944. doi: 10.3390/ijms20122944.
We present the first cytogenetic data for and with the aim of (1) investigating evolutionary events within and their relationships with other Lebiasinidae genera and (2) checking the evolutionary relationships between Lebiasinidae and Ctenoluciidae. Both species have a diploid number 2n = 36 with similar karyotypes and microsatellite distribution patterns but present contrasting C-positive heterochromatin and CMA banding patterns. The remarkable interstitial series of C-positive heterochromatin occurring in is absent in . Accordingly, shows the ribosomal DNA sites as the only GC-rich (CMA) regions, while shows evidence of a clear intercalated CMA banding pattern. In addition, the multiple 5S and 18S rDNA sites in contrast with single sites present in . Comparative genomic hybridization (CGH) experiments also revealed a high level of genomic differentiation between both species. A polymorphic state of a conspicuous C-positive, CMA, and (CGG)n band was found only to occur in females, and its possible relationship with a nascent sex chromosome system is discussed. Whole chromosome painting (WCP) and CGH experiments indicate that the species examined and share similar chromosomal sequences, thus supporting the relatedness between them and the evolutionary relationships between the Lebiasinidae and Ctenoluciidae families.
我们呈现了 和 的首例细胞遗传学数据，旨在：(1) 研究 和其他 Lebiasinidae 属内的进化事件及其关系；(2) 检查 Lebiasinidae 和 Ctenoluciidae 之间的进化关系。这两个物种的二倍体数均为 2n=36，具有相似的核型和微卫星分布模式，但存在着明显不同的 C 带阳性异染色质和 CMA 带模式。 在 中出现的显著的 C 带阳性间带系列在 中不存在。相应地， 仅显示 rDNA 位点为富含 GC（CMA）的区域，而 显示出明显的插入 CMA 带模式的证据。此外， 在 中存在多个 5S 和 18S rDNA 位点，而 在 中则只有单个位点。比较基因组杂交（CGH）实验也揭示了两个物种之间存在高水平的基因组分化。只有在 雌性中发现了一种明显的 C 带阳性、CMA 和（CGG）n 带的多态状态，其可能与新生的性染色体系统有关，对此进行了讨论。全染色体涂染（WCP）和 CGH 实验表明，所检查的 和 具有相似的染色体序列，因此支持它们之间的亲缘关系以及 Lebiasinidae 和 Ctenoluciidae 科之间的进化关系。
