Mutations Flashcards
What is a mutation?
Heritable alteration in gene or chromosome
and
the process that produces the alteration
What are the types of causes of mutations?
Exogenous causes
Endogenous causes
What are the types of exogenous causes of mutations?
Ionising radiation
Chemicals
Anti-cancer agents
What are the types of endogenous causes of mutations?
DNA replication defects
Transposable elements
How are mutations caused?
DNA damage
and then defective DNA repair
What are transposable elements?
Sections of DNA that can move as one unit to random sites in rest of DNA
Are transposable elements longer or shorter than genes?
Longer than genes
Do transposable elements exist in the free form?
No
they’re always contained in DNA molecules
Are transoposable elements more likely to move into longer genes or shorter genes?
More chance of them moving into longer genes
How can transposable elements cause mutations?
Can transpose into genes
disrupt gene
product product is dysfunctional
Can transpose into promoter region of gene
activate gene when it shouldn’t be
How can transposable elements have no effect?
If transpose into non-coding sections of DNA
or introns
What are the types of mutations?
Micro
Macro
What is the difference between micro and macro mutations?
Micro - few bases affeced
Macro - whole areas of chromosomes affected
What are the types of micro mutations?
Substitution
Insertion
Deletion
What are the types of macro mutations?
Translocation
Inversion
Duplication
Deletion
What are the types of substitution mutations?
Transition/transversion
Mis-sense/nonsense/silent/non-stop
What is a transition substitution mutation?
Base change to same type of base
- purine to purine
- pyrmidine to pyrimidine
What is a transversion substitution mutation?
Base change to different type of base
- purine to pyrimidine
- pyrimidine to purine