Mutations Mutations Any change in the DNA sequence
- Slides: 8
Mutations
Mutations • Any change in the DNA sequence of an individual • Mutations in reproductive cells can be incorporated into new offspring; these could be beneficial, harmful, or even fatal. • Mutations in body cells can affect the functionality of the cell or cause cancer.
• Mutagens are any agent that can cause a change in DNA: X rays, cosmic rays, UV light, nuclear radiation, chemicals like asbestos, benzene and formaldehyde
• Point mutations affect the shape of a protein by changing one base in the sequence, e. g. sickle cell anemia. • Frameshift mutations affect every amino acid that occurs after the insertion or deletion; effectively, changing the protein that is created.
Chromosomal Alterations • Chromosomal mutations are structural mutations in chromosomes. • Chromosomal mutations are usually fatal, or they cause sterility. • Some alterations are spontaneous.
• Deletion is when part of a chromosome is “cut out” • Insertion is when part of a chromatid breaks off and is added to its sister.
• Inversion is when part of a chromosome breaks off and reinserts itself backwards. • Translocation is when part of a chromosome breaks off and reattaches to a different chromosome.
DNA Repair • Cells have DNA “proofreaders” and “editors”. • They fix incorrect DNA sequences. • They are not perfect.
