Volobouev V T, Aniskin V M
Laboratoire de Zoologie, Mammifères et Oiseaux, Muséum National d'Histoire Naturelle, Paris, France.
Chromosome Res. 2000;8(4):295-304. doi: 10.1023/a:1009223210737.
Comparative G- and C-banding analysis in three species of rice rats, namely Oryzomys megacephalus from Peru and French Guiana, O. yunganus (Peru) and O. nitidus (Bolivia) was carried out. It revealed that Peruvian O. megacephalus (2N = 52, NFa = 62) and that from French Guiana (2N = 54, NFa = 64) differ from each other by one Rb translocation and one heterochromatic arm addition/deletion. Three further Rb translocations separate them from O. yunganus (2N = 58, NFa = 62). Only 16 out of 39 autosomal pairs of O. nitidus (2N = 80, NFa = 86) shared homologous banding patterns with O. yunganus, 4 of which were involved in tandem translocations to form the larger chromosomes in two other taxa. The study suggests that O. megacephalus, O. yunganus and O. laticeps studied previously form a monophyletic group in good agreement with earlier molecular and morphological data. By contrast, the limited homologous banding patterns found between them and O. nitidus cast doubt on its belonging to the same phylogenetic lineage. In the light of available chromosomal and molecular data, the significance of intra- and interspecies karyotypic variability within Oryzomys and its relevance to systematics and phylogeny of the genus are discussed.
对三种稻鼠进行了比较G带和C带分析，这三种稻鼠分别是来自秘鲁和法属圭亚那的巨头稻鼠、秘鲁的永氏稻鼠和玻利维亚的亮稻鼠。结果显示，秘鲁的巨头稻鼠（2N = 52，NFa = 62）和法属圭亚那的巨头稻鼠（2N = 54，NFa = 64）因一次罗伯逊易位和一次异染色质臂的增减而彼此不同。另外三次罗伯逊易位将它们与永氏稻鼠（2N = 58，NFa = 62）区分开来。亮稻鼠（2N = 80，NFa = 86）的39对常染色体中只有16对与永氏稻鼠具有同源带型，其中4对参与串联易位，在另外两个分类群中形成了更大的染色体。该研究表明，先前研究的巨头稻鼠、永氏稻鼠和宽头稻鼠形成了一个单系群，这与早期的分子和形态学数据高度一致。相比之下，它们与亮稻鼠之间有限的同源带型使人怀疑亮稻鼠是否属于同一系统发育谱系。根据现有的染色体和分子数据，讨论了稻鼠属种内和种间核型变异的意义及其与该属系统学和系统发育的相关性。
