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Molecular Basis of Heredity: Part 2. Genomes

Author(s): Raye L. Alford, PhD

Prokaryotic Genomes

There are two domains of prokaryotes: bacteria and archaea. Members of these groups do not have a cell nucleus or organelles bounded by membranes. Although there are exceptions, bacterial genomes do not typically have introns. On the other hand, the genes of organisms in the domain Archaea are sometimes a bit more complex and can have introns and other structural and regulatory elements similar to those found in eukaryotes. Prokaryotic genome sizes can vary widely. Some may be as small as a a few hundred thousand base pairs or as large as several million base pairs.