Departamento de Ciências Biológicas, Centro de Ciências Humanas e Naturais, Universidade Federal do Espírito Santo, Vitória, ES Brazil.
Genet Mol Biol. 2009 Apr;32(2):301-5. doi: 10.1590/S1415-47572009005000031. Epub 2009 Mar 13.
Juliomys is a small rodent from the family Cricetidae which inhabits the Atlantic forest and forests from Argentina to eastern Brazil. The three species recognized so far have different karyotypes. In this paper, we describe a new karyotype with 2n = 32, FN = 48 found in Juliomys specimens from a high-altitude area in the Atlantic forest of southern Brazil. The karyotype was analyzed after G- and C-banding and silver staining of the nucleolus organizer regions (Ag-NOR) and its G-banding patterns were compared with those of the newly described species Juliomys ossitenuis (2n = 20, FN = 36). The 2n = 32 karyomorph presented peculiar features and was very different from those of the other species of the genus: J. pictipes (2n = 36, FN = 34), J. rimofrons (2n = 20, FN = 34) and J. ossitenuis (2n = 20, FN = 36). Differences were mostly due to centric and tandem fusions, pericentric inversion and loss of heterochromatin. The karyotype represents a powerful tool to differentiate Juliomys species and our data suggest that the karyotype described herein belongs to a new species.
侏囊鼠属是仓鼠科的一种小型啮齿动物，分布于大西洋森林和阿根廷至巴西东部的森林中。目前已确认的三个物种具有不同的核型。本文描述了一种新的核型，2n=32，FN=48，发现于巴西南部大西洋森林高海拔地区的侏囊鼠标本中。核型经过 G 带和 C 带以及核仁形成区（Ag-NOR）的银染分析，并与新描述的物种侏囊鼠 ossitenuis（2n=20，FN=36）的 G 带模式进行了比较。2n=32 的核型表现出独特的特征，与该属的其他物种非常不同：J. pictipes（2n=36，FN=34）、J. rimofrons（2n=20，FN=34）和 J. ossitenuis（2n=20，FN=36）。差异主要归因于着丝粒和串联融合、着丝粒中心倒位和异染色质丢失。该核型是区分侏囊鼠物种的有力工具，我们的数据表明，本文所描述的核型属于一个新物种。
