13: Mechanisms of Microbial Genetics (Part B)
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- 13.1: Mutations
- A mutation is a heritable change in the DNA sequence of an organism. The resulting organism, called a mutant, may have a recognizable change in phenotype compared to the wild type, which is the phenotype most commonly observed in nature. A change in the DNA sequence is conferred to mRNA through transcription, and may lead to an altered amino acid sequence in a protein on translation.
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- 13.2: How Asexual Prokaryotes Achieve Genetic Diversity
- How then do organisms whose dominant reproductive mode is asexual create genetic diversity? In prokaryotes, horizontal gene transfer (HGT), the introduction of genetic material from one organism to another organism within the same generation, is an important way to introduce genetic diversity. HGT allows even distantly related species to share genes, influencing their phenotypes.
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- 13.3: Gene Regulation - Operon Theory
- Genomic DNA contains both structural genes, which encode products that serve as cellular structures or enzymes, and regulatory genes, which encode products that regulate gene expression. The expression of a gene is a highly regulated process. Whereas regulating gene expression in multicellular organisms allows for cellular differentiation, in single-celled organisms like prokaryotes, it ensures that a cell’s resources are not wasted making proteins that the cell does not need at that time.
Thumbnail: DNA Double Helix. (Public Domain; Apers0n).