Visualization of kinetochores in mammalian meiotic preparations and observations of argentophilic differences between mitotic and meiotic kinetochores.

Brief staining with AgNO3 was found to differentially stain the kinetochores of chromosomes from diakinesis - metaphase I and metaphase II nuclei of mammals. The results differ from those of Giemsa-stained or C-banded preparations as the silver-stained meiotic kinetochores are clearly distinguishable from both constitutive heterochromatin and euchromatin. Silver-staining is presented as a valuable method for the staining of meiotic material because it allows for the positive identification of centromeric position and orientation with respect to chiasmata. The nonargentophilic nature of the centromere (kinetochore) region of spermatogonial metaphase chromosomes in some species suggests a fundamental structural difference between mitotic and meiotic kinetochores.