NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.
Brown TA. Genomes. 2nd edition. Oxford: Wiley-Liss; 2002.
The primary function of a genome is to specify the biochemical signature of the cell in which it resides. In Part 2 we saw that the genome achieves this objective by the coordinated expression of genes and groups of genes, resulting in maintenance of a proteome whose individual protein components carry out and regulate the cell’s biochemical activities. In order to continue carrying out this function, the genome must replicate every time that the cell divides. This means that the entire DNA content of the cell must be copied at the appropriate period in the cell cycle, and the resulting DNA molecules must be distributed to the daughter cells so that each one receives a complete copy of the genome. This elaborate process, which spans the interface between molecular biology, biochemistry and cell biology, is described in Chapter 13.
Normally we think of replication as producing two identical copies of the genome, this being a requirement if the daughter cells are to have the same biochemical capabilities as the parent cell. In a general sense, genome replication does result in identical copies, but over time the genome undergoes change, nucleotide sequence alterations accumulating as a result of mutations, occasional errors in replication, and sequence rearrangements caused by recombination and related events.
In Chapter 14, you will learn how these sequence alterations occur and how some of them are repaired. You will realize that the accumulation of unrepaired sequence alterations is the basis for evolution of the genome, which in turn underlies the evolution of organisms, although in a complex manner that is not yet fully understood. These evolutionary themes are explored in the last two chapters of Genomes. Chapter 15 examines how molecular evolution has resulted in the vast variety of genomes present in the different organisms alive today, and Chapter 16 explains how the techniques of molecular phylogenetics can be used to make comparisons between the sequences of genes and of entire genomes, enabling evolutionary relationships to be inferred.
Chapter 13. Genome Replication
Chapter 14. Mutation, Repair and Recombination
- How Genomes Replicate and Evolve - GenomesHow Genomes Replicate and Evolve - Genomes
Your browsing activity is empty.
Activity recording is turned off.
See more...