Abstract: Chromosome aberrations were analyzed with the interspecific in vit ro fertilization system between human spermatozoa and zona2f ree hamster oocytes. The study was divided into three groups : cont rol , whole2body irradiation was taken from two individuals had exposed to 60Co 6 or 7 year ago ; and in vit ro irradiation with model at same doses. The f reqqency of sperm chromosome aberrations in the group of in vit ro radiation was much higher than that one of whole2body radiation with the same dose ( P < 0. 01) . Most of the st ructural abnormalities of chromosome observed in both radiation groups were breakage. The proportion of rejoining2type aberrations to breakage2type ones in whole2body irradiation group was significantly higher than that in vit ro one. The rate of Y2sperm to X2sperm in whole2body group was significantly higher than that in cont rol and in vit ro one. The result s indicated that the genetic harm in different stages of spermatogenesis and their irradiation sensitivity were two different concept s. The analysis of rejoining type aberration in human sperm may be especially important for assessing genetic effect s of radiation. The difference between the proportion of Y2Sperm to X-sperm in whole2body radiation group suggest that X2Linkage dominant Lethal mutations may be induced.

Key words: 60Co whole2body irradiaton, model dose, in vit ro irradiation, human sperm chromosome aberration.