Following with the discussion on mutagens, we took on chemicals that cause mutations through a variety of mechanisms (base analogs, nucleotide-altering chemicals, and chemicals that bind to DNA). We provided examples on their mechanism of action and on how they may affect the phenotype.
Then we discussed types of mutations at the nucleotide sequence level. We described the three main categories: nucleotide substitutions, insertion/deletions (indels), and allelic expansions (a.k.a dynamic mutations). We explained how they happen, when they alter the phenotype, and when and why they can be considered (or not) frameshift mutations.
We mentioned the mechanisms that cells have in place to fight off mutations (proofreading mechanism and repair systems) but details will be considered next week.
On Monday: Exam 2...!
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