Margulies L, Briscoe D I, Wallace S S
Mutat Res. 1986 Aug;162(1):55-68. doi: 10.1016/0027-5107(86)90071-0.
The combined effect of X-irradiation and transposon mobility on the frequencies of X-linked recessive lethals and dominant lethals was investigated in female hybrids in the P-M system of hybrid dysgenesis. X-linked lethals were measured in G2 hybrid dysgenic females whose X chromosome was derived from the M X P cross. To test for additivity or synergism, the mutation rate in irradiated dysgenic females was compared to that of unirradiated females as well as to irradiated nondysgenic hybrid females derived from M X M crosses. Eggs collected for 2 days after irradiation, were represented by the more radiation-sensitive A and B oocytes (about 75%) and the least sensitive C oocytes (about 25%). The production of X-linked lethal events in X-irradiated dysgenic females was 8.1%, as compared to 4.5% in dysgenic controls and 3.4% in irradiated, nondysgenic controls, demonstrating an additive effect of radiation and dysgenesis-induced genetic damage. The effect of irradiation on sterility of dysgenic hybrid females was a negative one, resulting in 20% less sterility than expected from an additive effect. The combined effect of radiation and dysgenesis on dominant lethality tested in A, B and C oocytes of the same hybrid females was synergistic. Egg broods collected for 3.5 days after irradiation showed that significantly more damage was induced in the presence of ionizing radiation in dysgenic females than in their nondysgenic counterparts. This effect was most obvious in B and C oocytes. The synergism observed may be related to the inability of cells to repair the increased number of chromosome breaks induced both by radiation and transposon mobility.
在杂种不育的P-M系统中，研究了X射线照射和转座子移动性对雌性杂种中X连锁隐性致死率和显性致死率的综合影响。在G2杂种不育雌性中测量X连锁致死率，其X染色体来自M×P杂交。为了测试加性或协同作用，将经照射的不育雌性的突变率与未照射的雌性以及来自M×M杂交的经照射的非不育杂种雌性的突变率进行比较。照射后2天收集的卵，由辐射敏感性较高的A和B卵母细胞（约75%）和敏感性最低的C卵母细胞（约25%）组成。经X射线照射的不育雌性中X连锁致死事件的发生率为8.1%，而不育对照为4.5%，经照射的非不育对照为3.4%，这表明辐射和不育诱导的遗传损伤具有加性效应。照射对不育杂种雌性不育的影响是负面的，导致不育率比加性效应预期的低20%。在同一杂种雌性的A、B和C卵母细胞中测试的辐射和不育对显性致死率的综合影响是协同的。照射后3.5天收集的卵群显示，不育雌性中存在电离辐射时比非不育雌性诱导的损伤明显更多。这种效应在B和C卵母细胞中最为明显。观察到的协同作用可能与细胞无法修复由辐射和转座子移动性诱导的增加的染色体断裂数量有关。
