Meiotic gene conversion and crossing over between dispersed homologous sequences occurs frequently in Saccharomyces cerevisiae.
Meiotic gene conversion and crossing over between dispersed homologous sequences occurs frequently in Saccharomyces cerevisiae.
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DOI：
10.1093/genetics/115.2.233
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发表时间：
1987-02
期刊：
影响因子：
3.3
通讯作者：
M. Lichten;R. Borts;James E. Haber
中科院分区：
文献类型：
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作者：
M. Lichten;R. Borts;James E. Haber
我们研究了正常leu2位点上的两个确定的leu2异等位基因和插入到其他四个基因组位置的含leu2质粒中的两个leu2异等位基因之间的减数分裂重组。在二倍体中，两个leu2标记存在于亲本同源物的等位基因位置上，leu2 +孢子的频率变化了38倍，以位置依赖的方式。这些结果表明，一个遗传区间内的重组可以通过该区间外至少2.7 kb的序列来调节。从二倍体中也恢复了Leu2+减数分裂分离，其中Leu2标记为一个异源等位基因，另一个Leu2异源等位基因插入到另一个基因组位置。这些异位相互作用的产物，在分散的leu2拷贝之间只有2.2 kb的同源性，恢复的频率与在相应的等位基因杂交中观察到的频率相当。这种高频率的异位减数分裂重组在杂交中被观察到，重组的伴侣可能在等位基因位置上配对。此外，这些异位重组中有很大一部分（22-50%）与侧翼序列的交叉有关。
We have examined meiotic recombination between two defined leu2 heteroalleles present at the normal LEU2 locus and in leu2-containing plasmids inserted at four other genomic locations. In diploids where the two leu2 markers were present at allelic locations on parental homologs, the frequency of Leu2+ spores varied 38-fold, in a location-dependent manner. These results indicate that recombination in a genetic interval can be modulated by sequences at least 2.7 kb outside that interval. Leu2+ meiotic segregants were also recovered from diploids where LEU2 was marked with one heteroallele, and the other leu2 heteroallele was inserted at another genomic location. These products of ectopic interactions, between dispersed copies of leu2 sharing only 2.2 kb of homology, were recovered at a frequency comparable to that observed in corresponding allelic crosses. This high frequency of ectopic meiotic recombination was observed in crosses where both recombining partners could potentially pair with sequences at an allelic position. In addition, a significant fraction (22-50%) of these ectopic recombinants were associated with crossing over of flanking sequences.