Montgomery E A, Huang S M, Langley C H, Judd B H
Laboratory of Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709.
Genetics. 1991 Dec;129(4):1085-98. doi: 10.1093/genetics/129.4.1085.
Ectopic recombination between interspersed repeat sequences generates chromosomal rearrangements that have a major impact on genome structure. A survey of ectopic recombination in the region flanking the white locus of Drosophila melanogaster identified 25 transposon-mediated rearrangements from four parallel experiments. Eighteen of the 25 were generated from females carrying X chromosomes heterozygous for interspersed repeat sequences. The cytogenetic and molecular analyses of the rearrangements and the parental chromosomes show: (1) interchromosomal and intrachromosomal recombinants are generated in about equal numbers; (2) ectopic recombination appears to be a meiotic process that is stimulated by the interchromosomal effect to about the same degree as regular crossing over; (3) copies of the retrotransposon roo were involved in all of the interchromosomal exchanges; some copies were involved much more frequently than others in the target region; (4) homozygosis for interspersed repeat sequences and other sequence variations significantly reduced ectopic recombination.
散布重复序列之间的异位重组会产生对基因组结构有重大影响的染色体重排。对黑腹果蝇白色基因座侧翼区域的异位重组进行的一项调查，从四个平行实验中鉴定出25种转座子介导的重排。这25种重排中有18种是由携带散布重复序列杂合X染色体的雌性产生的。对重排和亲本染色体的细胞遗传学和分子分析表明：（1）染色体间和染色体内重组体的产生数量大致相等；（2）异位重组似乎是一个减数分裂过程，受染色体间效应刺激的程度与正常交叉大致相同；（3）反转录转座子roo的拷贝参与了所有染色体间的交换；在目标区域，一些拷贝比其他拷贝参与的频率要高得多；（4）散布重复序列的纯合性和其他序列变异显著降低了异位重组。
