Spermatogenic delay and increased chiasma frequency in T70H/+ male mice with hydroxyurea–Trenimon limited spermatocyte populations

Abstract

T(1;13)70H/+ male mice were treated with hydroxyurea (HU) and Trenimon (T). This karyotype offers excellent possibilities for estimating number and position of chiasmata and segregation in meiotic anaphase I. By their cell-killing action during spermatogenesis, HU and T produce large gaps in the spermatogenic line. The surviving population between the gaps was analysed at diakinesis – metaphase I and metaphase II. We found by autoradiography a considerable retardation of the development from resting primary spermatocytes (RPS) to metaphase I and II as compared to untreated T70H/+ males. Furthermore we found increased chiasma frequencies in diakinesis – metaphase I (MI) and reduced nondisjunction frequencies at anaphse I as a result of the treatments applied. The latter effect could not be explained by the increased chiasma frequency.Key words: translocation, spermatogenesis, chiasmata, segregation, mouse, hydroxyurea.