Nash W G, O'Brien S J
H & W Cytogenetic Services, Inc., Sterling, VA.
Cytogenet Cell Genet. 1987;45(3-4):206-12. doi: 10.1159/000132455.
Trypsin G-banded karyotypes of eight species of Ursidae were prepared from retrovirus-transformed skin fibroblast cultures. The banding patterns of all bears are highly conserved, even though their diploid numbers range from 42 to 72. A comprehensive analysis of the homologous banding patterns within the Ursidae and with a hypothesized ancestral carnivore karyotype permitted the reconstruction of three significant chromosomal reorganization events that occurred during the evolution of the modern ursids. The first was a multichromosomal fissioning away from the biarmed (2n = 44) primitive carnivore karyotype, leading to six species of the Ursinae subfamily (2n = 78). The second was a comprehensive chromosome fusion in the lineage that led to the Ailuropodinae (giant panda) subfamily (2n = 44). The third event was a second, independent, but less extensive, centromeric fusion occurring in the line that led to the Tremarctinae (spectacled bear) subfamily (2n = 52). Ursidae karyotypes are not only highly conserved within the family but also exhibit extensive chromosome banding homology with other carnivore families.
从逆转录病毒转化的皮肤成纤维细胞培养物中制备了八种熊科动物的胰蛋白酶G带核型。尽管所有熊的二倍体数在42到72之间，但它们的带型高度保守。对熊科动物内部同源带型以及假定的原始食肉动物核型进行综合分析，使得能够重建现代熊科动物进化过程中发生的三个重要染色体重组事件。第一个事件是从双臂（2n = 44）原始食肉动物核型发生多染色体裂变，产生了熊亚科的六个物种（2n = 78）。第二个事件是在导致大熊猫亚科（2n = 44）的谱系中发生了全面的染色体融合。第三个事件是在导致眼镜熊亚科（2n = 52）的谱系中发生了第二次独立但程度较小的着丝粒融合。熊科动物的核型不仅在科内高度保守，而且与其他食肉动物科表现出广泛的染色体带型同源性。
