Mutations (L1)

• What are mutations defined as?

  Alterations in the genetic material of a cell or virus
• How can mutations be inherited?

  They can be inherited changes in the genetic material, where genes shift from one allele form to another
• What is a gene?

  A sequence of DNA or RNA in the genome that directly encodes functional molecules, such as RNA or proteins
• What is the basis of spontaneous mutation?

  Natural changes in the genetic material essential for generating genetic diversity, crucial for natural selection
• What is the approximate rate of spontaneous mutation?

  Approximately 3 new mutations per $10^8$ base pairs per generation
• How many new mutations are roughly found in each human child?

  About 200 new mutations
• How is net mutation calculated?

  Net mutation is calculated as DNA damage minus repair
• What role do DNA repair mechanisms play in mutation rates?

  They work to reduce the overall mutation rate
• How can net mutation rate be increased?

  By sunbathing
• Where is the mutation rate increased?

  Inside the soma
• What types of mutations affect protein-coding regions?

  • Point mutations (Silent, Nonsense, and Missense mutations)
  • Frameshift mutations (Insertion and Deletion mutations, also known as Indels)
• What is the impact of most mutations on phenotype?

  Most mutations have no impact on the phenotype
• Why do most mutations not cause noticeable changes in an organism?

  Because they affect non-coding regions of DNA or occur in genes that do not impact important functional aspects
• What percentage of the genome is crucial for function?

  1. 2%
• What do exons represent in the genome?

  Exons are the parts of the DNA that encode for proteins
• What are the differences between dominant and recessive mutations?

  • Dominant mutations:
  • Expressed in the phenotype with one copy (heterozygote behavior)
  • Recessive mutations:
  • Require two copies (homozygous state) to be expressed phenotypically
  • Can remain hidden in a population until two carriers mate
• Why must we prevent incest in relation to recessive mutations?


  Because we carry 1-2 recessive harmful mutations that could cause death