Random arrangement of chromosomes in a radial metaphase configuration

During metaphase II of spermatogenesis the chromosomes of the grasshopper, Melanoplus femurrubrum (De Geer), are arranged at the periphery of the metaphase plate in what has been termed the radial metaphyse configuration. Cells at this stage contain two long, three short, and either six or seven chromosomes of medium length. The arrangement of the chromosomes in the metaphase plate was analyzed by counting the number of medium-sized chromosomes which separated the two long chromosomes. In the 351 cells analyzed the frequencies of cells with the various types of arrangements agreed closely with those expected from a random arrangement of the chromosomes in the metaphase plate. The possible role of chromosome-to-chromosome connectives in the arrangement of the chromosomes in the radial configuration is discussed.Supported by Grant GB 23665 from the National Science Foundation Washington, D.C.