Telomere DNA shortening during each round of cell division, due to the end replication problem and as a result, limit the proliferative potential of normal somatic cells.

端粒dna在细胞增殖过程中因为末端复制问题而逐代缩短，因此，限制了正常体细胞的增殖能力。

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However, he said this proved that replication stress was the problem and that new tools could be developed to tackle it.

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