Mutations

My AP Biology Thoughts Unit 6 Gene Expression and Regulation

Welcome to My AP Biology Thoughts podcast, my name is Arthur Kim and I am your host for episode # 111 called Unit 6 Gene Expression and Regulation: Mutations. Today we will be discussing what genetic mutations are, the different types, as well as some of the possible effects.

Segment 1: Introduction to Mutations

• A mutation is any change to a sequence of DNA.
• They’re not always bad, as some mutations can arise that result in a more favorable phenotype.
• Mutations can also occur on the scale of chromosomes, often as a result in errors in meiosis.

Segment 2: More About Mutations

• On a strand of DNA, there are two main types of mutations that can occur.
• Point mutations are the result of swapping one base pair for another.
• Very often, these aren’t a big deal because only one amino acid will be affected or possibly unaffected since oftentimes more than one codon produces the same amino acid. In many cases, the protein that the mutated strand codes for will still be functional.
• Frameshift mutations are the result of an insertion or deletion of a base pair in a strand of DNA.
• These are often detrimental because they completely change the codons in an entire sequence of mRNA. As a result, the protein will be synthesized with completely different amino acids than what they’re supposed to be.
• This causes the protein to be nonfunctional.
• Frameshift mutations are the cause of several deadly genetic diseases such as Tay Sachs and cystic fibrosis.
• At the level of chromosomes, the types of mutations that can occur are deletions (part of the chromosome is lost), duplications (an extra copy of a part of a chromosome), inversions (the orientation of a segment of a chromosome is flipped), and translocation (two chromosomes exchange components).

Segment 3: Connection to the Course

• Genetic mutations are one of the main sources of variation within the gene pool. As a result, mutations are what allow for evolution to occur in populations, bringing about the diversity of life on Earth we see today.

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Music Credits:

• "Ice Flow" Kevin MacLeod...