棕色田鼠的细胞遗传学研究

Cytogenetic Studies of Brown Field-Mouse

本文首次报道棕色田鼠(Microtus mandarinus)的核型,核型公式为2n=50=2(M,T)+2SM+44T+♀XX(M,SM);♂XY(SM,ST)。发现第一对常染色体及X性染色体存在多态现象。在所研究的15只雌性个体中有7只雌性个体的细胞中只有1条X性染色体,性染色体组成为XO型,核型公式为2n=49=2(M,ST)+2SM+44T+XO。其中X性染色体不同于雄体中的X(SM),为M类型。本文提出的棕色田鼠3种核型与Brown等人(1964)提出的Microtus oregoni的3种核型(XO、YO、XY)有异。本文还阐述了染色体多态产生的机制和探讨了XO型个体发生的机理及其繁殖。

The karyotype of Brown Field-Mouse (Microtus mandarinus) is reported in this paper. The formula of karyotypes is:2?= 50 = 2(M,T) + 2SM + 44T + XX(M,SM)XY(SM,ST). The first pair of the autosomes and the X-chromosomes show polymorphism. Only one X-chromosome can be found in the seven out of the fifteen female specimens studied. The formula of its karyotypes is 2n = 49 = 2(M,ST)+2SM + 44T + XO. The X-chromosomes of these seven specimens are metacentric, and are different from the X(that is SM) of normal male, these are tha type M. Three kinds of karyotypes of Microtus mandarinus studied in this paper are different from the karyotypes (XO,OY,XY) of M. oregoni siudied by Brown et al. (1964). The mechanism of generation of chromosomal polymorphism is discussed. Individual ontogenesis mechanism of the type XO and its reproduction are also discussed.