Single molecule analysis of genome replication

所有细胞都含有生物体DNA的完整拷贝，即生命的遗传蓝图，被包装成称为染色体的离散单位。由于新细胞需要遗传物质的拷贝，因此在细胞分裂之前，染色体必须被完整而准确地复制。我们的研究旨在确定细胞如何确保每条染色体的复制在细胞分裂前完成。我们的实验数据揭示了数以百万计的细胞群体中染色体复制的平均模式——即先复制、后复制的区域，以此类推。然而，在初步数据中，我们发现单个细胞并不按照这种“平均”模式复制它们的染色体；单细胞的DNA复制模式被群体的平均值所掩盖。因此，DNA复制过程中的罕见问题，包括完成复制的延迟，目前还不能轻易检测到。因此，我们正在开发新的方法来直接测量DNA在单分子中的复制。在一种方法中，我们正在使用一种变革性的单分子测序技术来检测数千个长分子中的DNA复制模式。此外，我们将利用最新的成像技术来直接观察整个染色体中的DNA复制。这些互补的方法将首次揭示单个染色体上DNA复制的模式。这一点很重要，因为在单个细胞分裂中，一条染色体上的单个DNA复制错误可能导致包括癌症在内的基因组疾病。

All cells contain a complete copy of the organism's DNA, the genetic blueprint of life, packaged into discrete units called chromosomes. Since new cells need a copy of the genetic material, the chromosomes must be completely and accurately replicated before the cell can divide. Our research aims to determine how cells ensure that the replication of each chromosome is completed before cell division. Our experimental data have revealed the average pattern of chromosome replication in populations of millions of cells - that is the regions that are replicated first, second and so on. However, in preliminary data we have discovered that individual cells do not replicate their chromosomes with this 'average' pattern; the pattern of DNA replication in single cells is hidden by the population average. Consequently rare problems during DNA replication, including delays in completing replication, cannot currently be readily detected. Therefore, we are developing novel methods to directly measure DNA replication in single molecules. In one approach, we are using a transformative single-molecule sequencing technology to detect the pattern of DNA replication in thousands of long molecules. In addition, we will make use of recent advances in imaging technologies to directly visualise DNA replication in whole chromosomes. These complementary approaches will, for the first time, reveal the pattern of DNA replication on individual chromosomes. This is important because a single DNA replication error on one chromosome in a single cell division can give rise to genomic disorders, including cancer.