DNA Mutations Study Notes

DNA Mutations Overview

  • Definition: Mutations are heritable changes in genetic information.

Types of Mutations

  • Categories:

    1. Gene mutations: Changes in a single gene.

    2. Chromosomal mutations: Changes involving whole chromosomes.

Gene Mutations

  • Point mutations: Changes in one or a few nucleotides; occur during replication.

  • Frameshift mutations: Shift reading frame after the mutation due to insertion or deletion.

  • Substitution: Changes one base, often affecting a single amino acid.

  • Insertions: Adds bases, shifting codon groupings.

  • Deletions: Removes bases, also shifting codon groupings.

Chromosomal Mutations

  • Changes in number or structure of chromosomes: Can alter gene location or copy number.

  • Types:

    1. Deletion: Loss of all or part of a chromosome.

    2. Duplication: Extra copies of all or part of a chromosome.

    3. Inversion: Reverses direction of parts of a chromosome.

    4. Translocation: Part of one chromosome breaks and attaches to another.

Effects of Mutations

  • Vary widely: can be neutral, beneficial, or harmful.

  • Some mutations produce proteins with new/altered functions.

  • Causes: Errors in genetic processes or environmental factors.

  • Point mutations occur due to replication errors (approx. 1 in 10 million bases).

  • Accumulation of small changes over time can affect organisms significantly.