Karyotypic variation in the Andean rodent Phyllotis xanthopygus (Waterhouse, 1837) (Rodentia, Cricetidae, Sigmodontinae)
Karyotypic variation in the Andean rodent Phyllotis xanthopygus (Waterhouse, 1837) (Rodentia, Cricetidae, Sigmodontinae)
复制标题
安第斯啮齿动物 Phyllotis xanthopygus 的核型变异（Waterhouse，1837）（啮齿目、仓鼠科、Sigmodontinae）
作者：
C. Labaroni;Matías M. Malleret;A. Novillo;A. Ojeda;D. Rodriguez;P. Cuello;R. Ojeda;Dardo Martí;C. Lanzone
摘要Phyllotis xanthopygus （Waterhouse, 1837）是南美洲安第斯地区特有的一种啮齿动物。尽管它在阿根廷的地理分布很广，但很少有个体在细胞遗传学水平上进行了研究，只能通过常规染色。在这项工作中，利用固体染色、c带和碱基特异性荧光染料对阿根廷样品进行了染色体表征。分析了在胡胡伊省、卡塔马卡省和门多萨省北部和南部收集的22个标本。所有研究标本均为2n=38，多为双臂常染色体，常染色体为稳中心或亚稳中心。基本数在70和72之间变化。这些变化是由于在门多萨南部和胡胡伊的个体中存在染色体异型性。c -带显示在大多数染色体中存在组成性异染色质的近中心块。参与异型现象的外中心染色体在群体内和群体间的异染色质数量差异很大。此外，用荧光标记（DAPI和chromomycin A3）显示不同群体染色体中AT和GC富集区域的同源定位。然而，异型染色体对之间的比较表明，这种变异可能是复杂染色体重排的结果，可能涉及到异色片段的扩增和/或缺失。这些结果与分子研究一致，表明该分类单元群体内部和群体之间的遗传变异。
Abstract Phyllotis xanthopygus (Waterhouse, 1837) is an Andean rodent endemic to South America. Despite its wide geographical distribution in Argentina, few individuals have been studied on the cytogenetic level and only through conventional staining. In this work, chromosome characterization of Argentine samples of this species was performed using solid staining, C-banding and base-specific fluorochromes. Twenty two specimens were analyzed, collected in the provinces of Jujuy, Catamarca, and the north and south of Mendoza. All studied specimens showed 2n=38, having mostly the bi-armed autosomes, metacentric or submetacentric. Fundamental Number varied between 70 and 72. These changes were due to the presence of chromosome heteromorphisms in individuals from southern Mendoza and Jujuy. C-banding revealed pericentromeric blocks of constitutive heterochromatin in most chromosomes. Acrocentric chromosomes involved in heteromorphisms showed high variation in the amount of heterochromatin within and among populations. Additionally, banding with fluorochromes (DAPI and chromomycin A3) revealed homologous localization of AT and GC rich regions among chromosomes of the different populations analyzed. Comparisons among heteromorphic pairs suggested, however, that the variation might be the result of complex chromosome rearrangements, involving possibly amplifications and/or deletions of heterochromatic segments. These results are in accordance with molecular studies that indicate genetic variability within and among the populations of this taxon.