Abstract: The karyotypes were studied in 794 bone marrow cells from 11 Citellus dauricus (6 males and 5 females). The chromosome numbers of each cell were counted and analysed 89.17 per cent of 794 counted cells had the di-ploid number(2n= 36). The relative length, arm ratio and centromere index of each chromosome were calculated by measurements of 20 haploid chromosome sets(10 cells of each sex).The length and the size of the sex-chromosomes was very different from the autosomes. The results indicated that the X-chromosome was the largest one and the Y-chromosome was the smallest one in a diploid chromosome set.It was not difficult to find secondary constriction to occur regularly in certain regicrs cf lorg aim cf chromosome 10.

Key words: Ground squirrel, Citellus dauricus, Karyotype, Chimaera, Breakage of chromosome, Idiogram, Secondary constriction, Reciprocal translocation

摘要： 达乌尔黄鼠(Citellus dauricus)是分布于我国北方、蒙古和苏联等区域的一种中型啮齿动物。其染色体组型在国内文献中尚未见有报道,在国外文献中亦未见有详细报道。为此我们采用骨髓细胞染色体直接制片方法,并参考达乌尔黄鼠染色体的C分带和G分带(将另文报道,对其核型进行了分析研究,现报道如下。

关键词: 达乌尔黄鼠, 染色体组型, 嵌合体, 染色体断裂, 染色体组型模式图, 次缢痕, 相互易位