| Abstract: | The dose-response relationships of the induction of structural change in chromosomes after X-irradiation of spermatogonia have been determined from analyses of synaptonemal complexes in pachytene spermatocytes and from air-dried preparations of metaphase I. The dose-response curves were superficially the same shape, with a peak yield of cells containing a multivalent at 4 Gy, although only in the pachytene data was there any statistically significant hump. The pachytene preparations were much more sensitive, revealing nearly twice the proportion of cells containing multivalents than found at metaphase. |
