Chapter 5 - The genome

Abstract

In eukaryotes, the genes in the nucleus are distributed between a set of different chromosomes which makes up the genome, the complete set of genes, which are the functional units of heredity. The human genome, which contains 3.3 × 109 nucleotides, is distributed over 23 pairs of chromosomes. Since all of our cells have the same genome sequence, the shared and constant genome sequence acts differently in different cell types, responds to the environment, and changes throughout our lives. Therefore, the genetic information in the genome defines all the RNA and protein molecules, and directs when, in what types of cells, and in what quantity each protein is to be made. In this chapter, we review the bacterial and viral genome. Furthermore, we discuss the DNA packaging pattern inside eukaryotic cells, the chromosome structure, genome features, and genome evolution and its mechanism.