减数分裂是真核生物有性繁殖所必需的一个生命过程，其重组导致了父母本染色体之间DNA的交换，从而增加后代的遗传差异。减数分裂重组主要包括DNA双链断裂、加工、合成和连接，最终形成交换和非交换。其中，DNA合成是减数分裂重组中必不可少的一个环节。
当前减数分裂的重组模型只包括了DNA前导链的合成，而DNA合成相关基因在减数分裂中的作用还未有报道。迄今为止，减数分裂重组是否需要DNA后随链的合成更不清楚。本研究主要通过分子遗传学和细胞生物学等方法，分析了拟南芥DNA后随链合成的重要因子RFC1，发现该基因突变显著降低了植物的育性、减少了同源二价体形成的数目、非同源染色体间有明显的相互作用、形成大量多价体，最终导致染色体的不正常分离。将rfc1与重组不同通道的相关突变体杂交进行遗传分析，表明RFC1作用在交换的主要通道干涉敏感性途径。此外，突变体中剩下的交换表现出干涉不敏感，且依赖于该途径中起主要作用的MUS81的功能。
由此提出，减数分裂重组主要通道中间体dHJ的形成需要DNA后随链的合成，同时纠正了近30年来科学家一直认为，减数分裂重组DNA合成环节环节只需要DNA前导链。由于RFC1在多种生物中都有高度保守的单拷贝同源基因，暗示dHJ的形成需要DNA后随链的合成是一个保守的环节。相关结果发表在PLoS Genetics上。（生物谷Bioon.com）
doi: 10.1371/journal.pgen.1003039
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The DNA Replication Factor RFC1 Is Required for Interference-Sensitive Meiotic Crossovers in Arabidopsis thaliana
Wang Y, Cheng Z, Huang J, Shi Q, Hong Y, Copenhaver GP, Gong Z, Ma H.
During meiotic recombination, induced double-strand breaks (DSBs) are processed into crossovers (COs) and non-COs (NCO); the former are required for proper chromosome segregation and fertility. DNA synthesis is essential in current models of meiotic recombination pathways and includes only leading strand DNA synthesis, but few genes crucial for DNA synthesis have been tested genetically for their functions in meiosis. Furthermore, lagging strand synthesis has been assumed to be unnecessary. Here we show that the Arabidopsis thaliana DNA REPLICATION FACTOR C1 (RFC1) important for lagging strand synthesis is necessary for fertility, meiotic bivalent formation, and homolog segregation. Loss of meiotic RFC1 function caused abnormal meiotic chromosome association and other cytological defects; genetic analyses with other meiotic mutations indicate that RFC1 acts in the MSH4-dependent interference-sensitive pathway for CO formation. In a rfc1 mutant, residual pollen viability is MUS81-dependent and COs exhibit essentially no interference, indicating that these COs form via the MUS81-dependent interference-insensitive pathway. We hypothesize that lagging strand DNA synthesis is important for the formation of double Holliday junctions, but not alternative recombination intermediates. That RFC1 is found in divergent eukaryotes suggests a previously unrecognized and highly conserved role for DNA synthesis in discriminating between recombination pathways
