Maw H, Wallace S S, Margulies L
Department of Microbiology and Immunology, New York Medical College, Valhalla 10595.
Radiat Res. 1988 Sep;115(3):503-14.
The possible interaction between X-ray- and transposon-induced chromosome damage was monitored in the P-M system of hybrid dysgenesis in Drosophila melanogaster. One- to two-day-old F1 dysgenic males originating from a cross between M strain females and P strain males were irradiated with 5.5 Gy (550 rad) or used as controls to monitor X-Y translocations and transmission ratio distortion. Two 3-day sperm broods were sampled for the former and two 4-day broods for the latter to detect damage induced in the most radiosensitive cells. F1 nondysgenic males derived from M female to M male crosses (controls) were treated identically. X-Y chromosome translocations induced by P element mobility alone declined sharply with a decrease in temperature (18 versus 21 degrees C) and they were significantly reduced with aging of hybrid males from brood 2, 4-8 days of age, to brood 3, 7-11 days of age. No significant increase in translocations was observed when X irradiation and P-M dysgenesis were combined, showing no interaction between damages induced by the two mutator systems. In contrast, interaction was observed in transmission ratio distortion which was significantly increased by X irradiation of hybrid males derived from both reciprocal M X P and P x M crosses. The preferential elimination of P element-bearing autosomes occurred when either spermatocytes or spermatids were irradiated. An aging effect was also observed, resulting in less distortion in 9- to 14-day-old dysgenic males compared to 5- to 10-day-old hybrids.
在果蝇杂交不育的P-M系统中监测了X射线和转座子诱导的染色体损伤之间可能的相互作用。将源自M品系雌蝇与P品系雄蝇杂交的1至2日龄F1不育雄蝇用5.5 Gy（550拉德）进行辐照，或用作对照以监测X-Y易位和传递率畸变。对前者采集两批3日龄的精子，对后者采集两批4日龄的精子，以检测在最放射敏感细胞中诱导的损伤。对源自M雌蝇与M雄蝇杂交（对照）的F1非不育雄蝇进行相同处理。仅由P元件移动性诱导的X-Y染色体易位随着温度降低（18摄氏度对21摄氏度）而急剧下降，并且随着杂交雄蝇从第2批（4至8日龄）到第3批（7至11日龄）的老化而显著减少。当X射线照射与P-M不育相结合时，未观察到易位的显著增加，表明这两种诱变系统诱导的损伤之间没有相互作用。相反，在传递率畸变中观察到了相互作用，来自正反交M×P和P×M杂交的杂交雄蝇经X射线照射后传递率畸变显著增加。当精母细胞或精子细胞受到照射时，会优先消除携带P元件的常染色体。还观察到了老化效应，与5至10日龄的杂种相比，9至14日龄的不育雄蝇的畸变较少。
