DNA replication is the process by which a molecule of DNA is duplicated. When a cell divides, it must first duplicate its genome so that each daughter cell winds up with a complete set of chromosomes.
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DNA replication is probably one of the most amazing tricks that DNA does. If you think about it, each cell contains all of the DNA you need to make the other cells. And we start out from a single cell and we end up with trillions of cells. And during that process of cell division, all of the information in a cell has to be copied, and it has to be copied perfectly. And so DNA is a molecule that can be replicated to make almost perfect copies of itself. Which is all the more amazing considering that there are almost three billion base pairs of DNA to be copied. And replication uses DNA polymerases which are molecules specifically dedicated to just copying DNA. Replicating all of the DNA in a single human cell takes several hours of just pure copying time. At the end of this process, once the DNA is all replicated, the cell actually has twice the amount of DNA that it needs, and the cell can then divide and parcel this DNA into the daughter cell, so that the daughter cell and the parental cell in many case are absolutely genetically identical.
Lawrence C. Brody, Ph.D.
Chief & Senior Investigator, Genome Technology Branch; Head, Molecular Pathogenesis Section
Dr. Brody investigates the genetics of breast cancer and neural tube defects. As chief of the NHGRI Genome Technology Branch's Molecular Pathogenesis section, he is interested in studying genetic mutations that lead to perturbations in normal metabolic pathways and cause disorders such as cancer and birth defects. His laboratory investigates mutations in two breast cancer-linked genes, breast cancer gene 1 (BRCA1) and breast cancer gene 2 (BRCA2). Dr. Brody's laboratory was among the first to report that women carrying BRCA1 or BRCA2 mutations have a higher risk of developing both breast and ovarian cancer than women without such mutations.