A comparative study of the frequencies of radiation-induced chromosome aberrations in somatic and germ cells of the Rhesus monkey (Macaca mulatta).

Frequencies of radiation-induced chromosome aberrations in spermatogonia, peripheral blood lymphocytes and bone-marrow cells of the rhesus monkey (Macaca mulatta) and in human blood lymphocytes, were determined at different exposures of X-rays. The dose-response curve for the induction of reciprocal translocations in spermatogonia suggested a "hump" at about 200 rad. The absolute frequencies of chromosome aberrations in somatic and germ cells of the rhesus monkey were low in comparison with most other mammalian species and the ratio between aberrations in the two tissues was 25 to 1 at the 100 rad level. Although the numbers of "effective chromosome arms" in man and rhesus monkeys are similar (81 vs. 83), the rhesus monkey showed a lower rate of induction of dicentrics in blood lymphocytes than man at all doses, reaching statistical significance at the 300 rad level.