Читать книгу Snyder and Champness Molecular Genetics of Bacteria - Tina M. Henkin - Страница 127

The discussion of the replication and structure of the bacterial genome ignores the complexity of the sequences and the functions they encode. Advances in DNA-sequencing technologies are drastically reducing both the time it takes to sequence DNA and the cost of DNA sequencing. We are now at a time when determining the genomic sequence of a newly discovered bacterium is often one of the earliest steps in trying to fully characterize the functions of a new species. In addition, there are also a large number of studies where DNA from a particular environment or a consortium of organisms is chosen for DNA sequencing instead of that of a single organism derived from pure culture. Bacterial and archaeal genomes are in some ways more amenable to genome analysis than eukaryotic genomes because they are relatively small, ranging from ca. 0.5 megabases (Mb) for some obligate parasites to around 10 Mb for some free-living bacteria. They contain few introns and much less repetitive DNA than eukaryotic genomes. Chapter 13 deals with ideas for how genomes are structured and the tools we use to study them.