mutations

• Mutation


  A change that occurs in our DNA sequence, either due to mistakes when the DNA is copied or as the result of environmental factors such as UV light and cigarette smoke
• Protein synthesis


  1. Transcription

  2. Translation
• Codon

  Sequence of three nucleotides in mRNA that specifies a particular amino acid
• Mutation

  An anomaly in the genes caused by incorrect copying of mRNA during transcription
• Mutagen

  An agent that causes alteration in the DNA and can lead to permanent mutations in the DNA sequence
• Point mutation


  A type of mutation where one single nucleotide base is deleted, added or altered
• Frameshift mutation


  A mutation where the normal sequence of codons is disorganized by the insertion or deletion of one or more nucleotides, given that the number added or deleted is not a multiple of three
• Silent mutation

  A type of point mutation where a nucleotide base is altered but the same amino acid is produced
• Nonsense mutation


  A type of point mutation that results in the formation of a stop codon due to the substitution of one nitrogenous base
• Missense mutation


  A type of point mutation where one nitrogenous base is replaced and the result is an altered codon but does not form a stop codon
• Conservative mutation


  A type of missense mutation where the new amino acid formed has the same properties as the one that was supposed to be produced
• Non-conservative mutation


  A type of missense mutation where the new amino acid formed has different properties than the one that was supposed to be produced
• Silent mutation happens when a nitrogenous base is altered but the same amino acid is produced
• Many codons can code for the same amino acid
• Frameshift mutation

  Leads to the abnormal protein with an improper amino acid sequence that can be either longer or shorter than the normal protein
• Types of chromosomal mutations


  • Deletion
  • Duplication
  • Inversion
  • Insertion
  • Translocation
• Sickle cell anemia is caused by a single substitution mutation in the gene responsible for hemoglobin production
• Albinism is caused by the deletion of the tyrosinase gene
• Cystic fibrosis is most commonly caused by a deletion mutation that affects the CFTR gene
• Down syndrome is caused by a translocation during meiosis that transfers most of chromosome 21 onto chromosome 14