BIOSC 0160 Lecture Notes - Lecture 16: Point Mutation, Missense Mutation, Allele Frequency
25 Oct 2017
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Lecture 16: process of evolution: resistance to antibiotics, mycobacterium tuberculosis: non-motile (does not swim around, doesn"t have flagella), rod-shaped, spreads through tiny droplets in the air. The small particles can be caught in air currents and can be spread throughout a room. In the late 1980"s, rates of tb started to surge. One reason was hiv, and the other was due to evolution of drug-resistant strains: tb in one patient"s body was completely resistant to rifampin. There was a single point mutation in rpob (tcg to ttg). Missense mutation. rpob encodes the beta subunit of rna poly: under normal conditions, mutant forms of rna poly do not work as well as the normal form. They have a small population, and their transcription and translation was slower than normal bacteria. Are not dominant in the population since they grow more slowly: antibiotic therapy kills normal bacteria, but the mutants are resistant and grow slowly but persist in the environment.
