Frequency of Dicentric Bridges in Meiosis in the Grasshopper Gesonia punctifrons , Produced by Different Dosages of X-Rays

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Abstract
Dicentric bridges have never been observed in non-irradiated material from this sp. Male grasshoppers were irradiated with doses varying from 40r to 320r, and the frequency of dicentric bridges observed in the testes at anaphase of 1st meiosis. The percentage of bridges is directly proportional to dosage, and the frequency remains rather constant at different hours after irradiation. The authors conclude that each dicentric bridge, accompanied in each case by a chromosome fragment, was caused by a single hit and a single break prior to chromosome duplication, with subsequent "healing" of the broken ends of the chromatids after duplication.