Anostomidae are a neotropical fish family rich in number of species. Cytogenetically, they show a conserved karyotype with 2n = 54 chromosomes, although they present intraspecific/interspecific variations in the number and chromosomal location of repetitive DNA sequences. The aim of the present study was to perform a comparative description of the karyotypes of two populations of Leporinusfriderici Bloch, 1794 and three populations of Leporellusvittatus Valenciennes, 1850. We used conventional cytogenetic techniques allied to fluorescence in situ hybridization, using 18S ribosomal DNA (rDNA) and 5S rDNA, a general telomere sequence for vertebrates (TTAGGG)n and retrotransposon (RTE) Rex1 probes. The anostomids in all studied populations presented 2n = 54 chromosomes, with a chromosome formula of 32m + 22sm for L.friderici and 28m + 26sm for L.vittatus. Variations in the number and location of the 5S and 18S rDNA chromosomal sites were observed between L.friderici and L.vittatus populations and species. Accumulation of Rex1 was observed in the terminal region of most chromosomes in all populations, and telomere sequences were located just on all ends of the 54 chromosomes in all populations. The intraspecific and intergeneric chromosomal changes occurred in karyotype differentiation, indicating that minor chromosomal rearrangements had present in anostomid species diversification.

中文翻译：

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Leporinusfriderici和Leporellusvittatus种群（Characiformes，Anostomidae）之间的比较细胞遗传学：专注于重复的DNA元素。

拟蝇科是一个新热带鱼类科，种类丰富。在细胞遗传学上，它们显示出保守的核型，具有2n = 54条染色体，尽管它们在重复DNA序列的数量和染色体位置上存在种内/种间差异。本研究的目的是对1850年的两个Leporinusfriderici Bloch和三个Leporellusvittatus Valenciennes的核型进行比较描述。我们使用18S核糖体DNA（rDNA）技术结合了传统的细胞遗传技术，进行了荧光原位杂交。 ）和5S rDNA（脊椎动物（TTAGGG）n和逆转座子（RTE）Rex1探针的通用端粒序列）。在所有研究的种群中，乙酰胺类动物呈现2n = 54条染色体，对于L.friderici而言，其染色体公式为32m + 22sm，而对于L.则为28m + 26sm。维塔图斯。在弗氏乳杆菌和vittatus种群和物种之间观察到了5S和18S rDNA染色体位点的数量和位置的变化。在所有种群的大多数染色体的末端区域都观察到Rex1的积累，端粒序列恰好位于所有种群的54条染色体的所有末端。种内和属间染色体变化发生在核型分化中，表明在Anantosmid物种多样化中存在较小的染色体重排。端粒和端粒序列恰好位于所有种群的54条染色体的所有末端。种内和属间染色体变化发生在核型分化中，表明在Anantosmid物种多样化中存在较小的染色体重排。端粒和端粒序列恰好位于所有种群的54条染色体的所有末端。种内和属间染色体变化发生在核型分化中，表明在Anantosmid物种多样化中存在较小的染色体重排。