recombination site

The using of co-transformation system, site-specific recombination system ( FLP/ FRT? Cre/ lox? R/ RS and Gin/ gix systems) and transposable element system ( Ac/ Ds transposable element system) in breeding marker-free transgenic plants were reviewed in this paper.

本文综述了共转化系统、位点特异性重组系统（包括FLP/FRT、Cre/lox、R/RS及Gin/gix系统）和转座子系统（Ac/Ds转座子系统）在培育无选择标记转基因植物中的应用。

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Construction of FLP/ frt site-specific recombination system for monocotyledonous plants

单子叶植物的FLP/frt位点特异性重组系统的构建

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Gene targeting is a rising technology in molecular biology, which is defined as the introduction of exogeneous DNA to specific site in genome by homologous recombination, and consequently change the hereditary character of the cell.

基因打靶技术是一项新兴的分子生物学技术，是利用外源DNA与受体细胞染色体DNA上的同源序列之间发生重组，并整合在预定位点上，从而改变细胞遗传特性的方法。

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Conclusion Repeat sequence and strong topoisomerase ⅱ cleavage site around the breakpoint may predispose double-strand DNA breaks and recombination, which, in addition to the nonhomologous end-joining mechanism, may contribute as important factors to the gene deletion.

结论推测重复序列、断裂点附近较强的拓扑异构酶Ⅱ酶切位点关联易引起基因的断裂重组，加上非同源末端连接修复机制等综合因素可能是导致基因缺失的重要原因。

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Compared to those of two previously reported cases abroad, we found that the breakpoint may be situated in the topoi-somerase ⅱ cleavage site. A working model has been proposed for the mechanism of DNA illegitimate recombination in t ( 15; 17).

与以前国外所报道的二例病例进行了比较，发现断裂点可能处于拓扑异构酶Ⅱ裂解位点，由此，我们对t（15；17）中DNA异常重组的机制提出了一个工作模型。

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