| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2005: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2004: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
Development of a new system for the detection of genetic effect caused by ionizing radiation has been attempted. 500 mouse genomic DNA samples for Southern blot hybridization analyses have been prepared in a parallel research project for investigating the genetic effect of ionizing radiations by direct DNA sequencing analyses at the specific mouse genomic loci.
Southern analyses of each mouse DNA sample was performed at ten STS loci (130568, 131443, 141035, 142454, 144547, 161305, 178225, 185566, 186223, and 225927), two genomic gene loci (Aprt and Hprt), and a hyper-variable tandem repeat locus (Ms6-hm), where also direct DNA sequencing analysis has been performed. As a result, any changes in size of restriction fragments have not been observed at the STS loci and the genomic gene ones in the offspring of the parents exposed to 1 or 3 gray of gamma ray. On the other hand, a new mutation was detected by the direct DNA sequencing analysis at the UniSTS 178225 where any size shifts of restriction fragments have not been observed. Surprisingly, any size shifts of restriction fragments have also not been observed at the Ms6-hm hyper-variable tandem repeat locus in the same mouse. These results suggested that the direct DNA sequencing analysis was a powerful research tool for the detection of the genetic effect caused by ionizing radiation. Also the results suggested that the occurrence of dynamic mutation at the hyper-variable tandem repeat Ms6-hm locus may not be very useful for detecting the genetic effect of mutagens, because this did not necessarily correspond to the occurrence of a new mutation somewhere else.
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