CHROMOSOME CHANGES IN RAT EMBRYOS FOLLOWING X-IRRADIATION.

A study was made of chromosome changes in rat embryos after exposure to teratogenic doses of x-rays. Two methods were used for chromosome analysis: a direct method permitting analysis of chromosomes soon after removal of the embryos from the uterus, and a method in which the embryonic cells were first grown in tissue culture for several days after removal, before they were processed. The direct method proved superior to the tissue culture method for demonstrating early chromosome changes. A half day after irradiation a high incidence of chromosomal aberrations was found which dropped rapidly and returned to almost normal values after several days.