| Abstract: | In experiments with females of lines with an impaired DNA repair systems mei-9 (impaired excision repair) and mei-41 (impaired postreplicative repair), a method of successive irradiation by X-rays (1000 R) and hyperthermia (+37 degrees C) action was used for the purpose of defining a moment when DNA repair takes place in oogenesis. Repair in mature mei-41 oocytes judged of by synergism effect of the both factors acting was ascertained to take place right after X-raying (prior to DNA replication) and being absent at the fertilization period (at the time of or after DNA replication). DNA repair in mei-9 females was not registered in both cases. On the basis of these facts, it is suggested that coordination of various DNA repair systems is necessary for damaged chromosomes to be repaired. It is also concluded that the method used can be regarded as an effective technique in the study of mutation process. |
