The effect of exposure rate on translocation induction in somatic and germ cells of the mouse (Mus musculus).

The effect of exposure rate on translocation induction in spermatogonia, scored as multivalents in descending spermatocytes and bone-marrow cells of the mouse (Mus musculus) was investigated 65--100 days after X-ray and gamma-ray exposures of 400 R. In the range of exposure rates studied there was a decreased in frequency in bone-marrow cells from 17.1% at 130 R/min to 4.6% at 0.0287 R/min. In spermatogonia the frequency dropped from 6.7% at 130 R/min to 1.9% at 0.0287 R/min. The data obtained for both tissues fitted a straight line when plotted against the logarithm of the exposure rate. The ratios between aberration frequencies in bone-marrow cells and spermatogonia, with a mean value of 2.74, were independent of exposure rate.