Selker E U, Cambareri E B, Jensen B C, Haack K R
Institute of Molecular Biology, University of Oregon, Eugene 97403.
Cell. 1987 Dec 4;51(5):741-52. doi: 10.1016/0092-8674(87)90097-3.
Introduction of DNA into Neurospora crassa can lead to sequence instability in the sexual phase of the life cycle. Sequence instability was investigated by using a set of strains transformed with single copies of a plasmid including host sequences, Neurospora sequences deleted from the host genome, and foreign sequences. The sequences already represented in the host were rearranged at high frequency in a cross. In general, both elements of the duplication, that from the plasmid and that from the host, became rearranged, whether or not they were linked. Unique sequences were left unaltered. Cytosine residues in the rearranged sequences typically became methylated de novo. Results from tetrad analyses indicated that the rearrangements occur before meiosis, during a stage between fertilization and karyogamy. We suggest that this previously unrecognized genetic process, RIP (rearrangement induced premeiotically), may contribute diversity for evolution and also maintain the gross organization of the genome.
将DNA导入粗糙脉孢菌会导致其生命周期有性阶段的序列不稳定。通过使用一组用包含宿主序列、从宿主基因组中缺失的脉孢菌序列以及外源序列的单拷贝质粒转化的菌株来研究序列不稳定情况。宿主中已存在的序列在杂交中高频重排。一般来说，重复的两个元件，即来自质粒的和来自宿主的，无论是否连锁，都会发生重排。独特序列保持不变。重排序列中的胞嘧啶残基通常会从头甲基化。四分体分析结果表明，重排在减数分裂之前发生，即在受精和核融合之间的阶段。我们认为这种以前未被认识的遗传过程，即减数分裂前诱导重排（RIP），可能为进化贡献多样性，同时也维持基因组的总体组织。
