Plant Sciences Department and Committee on Genetics, University of Arizona, Tucson, Arizona 85721.
Genetics. 1983 Nov;105(3):723-31. doi: 10.1093/genetics/105.3.723.
Cytological observations of quadrivalents of heterozygous translocations in Gossypium hirsutum L. demonstrate that, in addition to alternate-1 and alternate-2 orientations, a third alternate orientation (alternate-3), which occurs as a three-dimensional, V-type configuration, can be identified.-Two additional types of disjunctions, the centromere orientations of which are rotational modifications of either adjacent or alternate configurations, were also observed in quadrivalents of a translocation heterozygote. These two types are rare, and both appear in the form of the Roman numeral X . The X and the alternate-3 types also occur in quadrivalents of an autoploid of G. hirsutum.-The two X types, along with adjacent-1, adjacent-2, alternate-1 and alternate-2 orientations, represent the six possible types of planar 2 x 2 random orientation of the four centromeres of a quadrivalent. Including the three-dimensional alternate-3 type, there are seven types of orientation.
棉种异源易位四价体的细胞学观察表明，除了交替-1 和交替-2 取向外，还可以识别出第三种交替取向（交替-3），它呈三维 V 型构型。在易位杂合体的四价体中，还观察到了两种额外的分离类型，其着丝粒取向是相邻或交替构型的旋转修饰。这两种类型很少见，都以罗马数字 X 的形式出现。X 和交替-3 类型也出现在棉属同源四倍体的四价体中。X 型有两种，与相邻-1、相邻-2、交替-1 和交替-2 取向一起，代表四价体四个着丝粒的二维 2x2 随机取向的六种可能类型。包括三维交替-3 类型，共有七种取向类型。
