Araújo Naiara Pereira, Kuhn Gustavo Campos Silva, Vieira Flávia Nunes, Morcatty Thaís Queiroz, Paglia Adriano Pereira, Svartman Marta
Laboratório de Citogenômica Evolutiva, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627-Pampulha, 31270-901 Belo Horizonte, MG, Brazil.
Laboratório de Ecologia e Conservação, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627-Pampulha, 31270-901 Belo Horizonte, MG, Brazil.
Int J Genomics. 2017;2017:5935380. doi: 10.1155/2017/5935380. Epub 2017 Aug 15.
South American Akodontini rodents are characterized by a large number of chromosome rearrangements. Among them, the genus has been extensively analyzed with classical and molecular cytogenetics, which allowed the identification of a large number of intra- and interspecific chromosomal variation due to Robertsonian rearrangements, pericentric inversions, and heterochromatin additions/deletions. In order to shed some light on the cause of these rearrangements, we comparatively analyzed the karyotypes of three Akodontini species, (2n = 14, FN = 19), (2n = 24, FN = 42), and (2n = 34, FN = 34), after GTG- and CBG-banding. The karyotypes differed by Robertsonian rearrangements, pericentric inversions, centromere repositioning, and heterochromatin variation. Genome comparisons were performed through interspecific fluorescent in situ hybridization (FISH) with total genomic DNAs of each species as probes (GISH). Our results revealed considerable conservation of the euchromatic portions among the three karyotypes suggesting that they mostly differ in their heterochromatic regions. FISH was also performed to assess the distribution of telomeric sequences, long and short interspersed repetitive elements (LINE-1 and B1 SINE) and of the endogenous retrovirus mysTR in the genomes of the three species. The results led us to infer that transposable elements have played an important role in the enormous chromosome variation found in Akodontini.
南美洲的阿科东鼠属啮齿动物的特点是存在大量染色体重排。其中，该属已通过经典细胞遗传学和分子细胞遗传学进行了广泛分析，这使得能够识别由于罗伯逊重排、臂间倒位和异染色质增减而导致的大量种内和种间染色体变异。为了阐明这些重排的原因，我们在进行GTG和CBG显带后，对三种阿科东鼠属物种（阿氏鼠2n = 14，FN = 19；圣氏鼠2n = 24，FN = 42；黑腹鼠2n = 34，FN = 34）的核型进行了比较分析。这些核型在罗伯逊重排、臂间倒位、着丝粒重新定位和异染色质变异方面存在差异。通过以每个物种的总基因组DNA作为探针进行种间荧光原位杂交（FISH）（基因组原位杂交，GISH）来进行基因组比较。我们的结果显示，三种核型的常染色质部分有相当程度的保守性，这表明它们的主要差异在于异染色质区域。还进行了FISH以评估端粒序列、长短散在重复元件（LINE-1和B1 SINE）以及内源性逆转录病毒mysTR在这三个物种基因组中的分布。结果使我们推断，转座元件在阿科东鼠属中发现的巨大染色体变异中发挥了重要作用。
