Kim J S, Rose A M
Genome. 1987 Jun;29(3):457-62. doi: 10.1139/g87-079.
We have studied the effect of gamma radiation on recombination frequency for intervals across the cluster of linkage group I in Caenorhabditis elegans. Recombination frequency increased approximately twofold across the dpy-5-unc-13 interval after treatment with 2000 rads (1 rad = 10 mGy) of cobalt 60 gamma radiation. Several factors affecting the magnitude of the increase have been characterized. Recombination frequency increased more with higher doses of radiation. However, the increase in recombination frequency with increasing dose was accompanied by a reduced average number of progeny from radiation-treated individuals. The amount of the increase was affected by meiotic stage, age at the time of treatment (premeiotic), and radiation dose. The increase in recombination was detectable in the B brood and remained elevated for the remainder of egg production. X-chromosome nondisjunction was also increased by radiation treatment. A high frequency of the recombinant progeny produced with radiation treatment were sterile unlike their nonrecombinant siblings. When parameters affecting recombination frequency are held constant during treatment, chromosomal regions of high gene density on the meiotic map increased more (fourfold) than an adjacent region of low gene density (no increase). The greatest increase was across the dpy-14-unc-13 interval near the center of the gene cluster. These results may suggest that the physical length of DNA per map unit is greater within the cluster than outside.
我们研究了γ辐射对线虫I连锁群簇中各区间重组频率的影响。用2000拉德（1拉德 = 10毫戈瑞）的钴60γ辐射处理后，dpy - 5 - unc - 13区间的重组频率增加了约两倍。已对影响增加幅度的几个因素进行了表征。辐射剂量越高，重组频率增加得越多。然而，随着剂量增加，重组频率的增加伴随着辐射处理个体后代平均数量的减少。增加的幅度受减数分裂阶段、处理时的年龄（减数分裂前）和辐射剂量的影响。在B代中可检测到重组的增加，并且在剩余的产卵过程中一直保持升高。辐射处理也增加了X染色体不分离。与未重组的同胞不同，经辐射处理产生的高频率重组后代是不育的。当处理过程中影响重组频率的参数保持恒定时，减数分裂图谱上基因密度高的染色体区域增加得更多（四倍），而相邻的基因密度低的区域则没有增加。最大的增加发生在基因簇中心附近的dpy - 14 - unc - 13区间。这些结果可能表明，基因簇内每图谱单位的DNA物理长度比外部更大。
