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早期研究认为,染色体DNA的复制,是通过DNA聚合酶的催化作用,以DNA为直接模板进行核苷酸聚合的过程。这一过程要求复制叉单向移动,而且所有的DNA聚合酶的合成方向均为从5′→3′末端.这种看法曾使人们迷惑不解。后来发现,新合成的DNA双链之一,即前导链,是沿5′→3′方向连续合成,正与起始点的移动方向一致。而另一条链,即后随链,则沿5′→3′方向作不连续合成,与复制叉的移动方向完全相反。后随链不连续合成过程包括:RNA的启动,引物的去除,缺口的填补,
Early studies suggest that chromosomal DNA replication is catalyzed by DNA polymerase and that DNA is used as a direct template for nucleotide polymerization. This process has led to puzzlement that the fork must move unidirectionally and that all DNA polymerases are synthesized from the 5 ’to the 3’ end. It was later found that one of the newly synthesized DNA double strands, the leading strand, was synthesized continuously in the 5 ’→ 3’ direction and was in the same direction as the starting point. While the other chain, that is, the following chain, is synthesized discontinuously in the 5 ’→ 3’ direction in exactly the same direction as the transfer fork. Follow-chain discontinuous synthesis processes include: RNA initiation, primer removal, gap filling,