Genetics Department, Iowa State University, Ames, Iowa 50011.
Genetics. 1980 Apr;94(4):969-78. doi: 10.1093/genetics/94.4.969.
The timing of mutator activity of Mu in maize was tested in three ways: (1) by allelism tests of phenotypically similar male-transmitted mutants, (2) by studying the clustering of phenotypically similar mutants as demonstrated by ear maps and the subsequent allelism tests of these mutants, and (3) by the induction of somatic sectors in Mu plants heterozygous for plant and endosperm marker genes. Allelism tests of phenotypically similar mutants in outcrosses of Mu plants as males established that 18.6% were allelic and that premeiotic mutants are induced. This conclusion was supported by ear maps of Mu-bearing plants, which revealed sectors of seeds that produced plants bearing phenotypically similar allelic mutants. The smallness of these sectors indicated that the premeiotic activity of Mu that gave rise to them occurred very late. The lack of visible sectors in mature sporophytic, endosperm and aleurone tissue in plants carrying Mu supports the conclusion that the mutator activity of Mu does not occur throughout the ontogeny of the plant and seems to be restricted to a time shortly before and/or during meiosis.
我们通过三种方法来测试 Mu 在玉米中的突变剂活性的时间：（1）表型相似的雄性传递突变体的等位基因测试，（2）通过耳图谱研究表型相似的突变体的聚类，以及随后对这些突变体的等位基因测试，以及（3）通过 Mu 植物的体细胞组织的诱导，这些 Mu 植物杂合有植物和胚乳标记基因。在 Mu 植物作为雄性的杂交中，表型相似的突变体的等位基因测试表明，有 18.6%是等位基因的，并且诱导了减数分裂前的突变体。这一结论得到了携带 Mu 的植物的耳图谱的支持，该图谱揭示了产生具有表型相似等位基因突变体的植物的种子区域。这些区域的小尺寸表明，导致它们的 Mu 的减数分裂前活性发生得非常晚。携带 Mu 的植物的成熟孢子体、胚乳和糊粉层组织中没有可见的区域，这支持了 Mu 的突变剂活性不是在植物的整个个体发生过程中发生的结论，而且似乎仅限于减数分裂前和/或减数分裂期间的很短时间。
