What is an Ames test?
STANDARD TEST TO determine if a new compound is mutagenic
Forward Mutation
A mutation that alters a wild-type allele and generates a mutant
Reverse mutation
alters a mutant and reverts the DNA to its original state
true reversion
A type of mutation that exactly reverses the effect of the original mutation
intragenic reversion
A second mutation within a single gene that restores wild-type function
Second site reversion
A specific type of reversion taking place at a location separate from the originally altered site to restore the wildtype
How does strand slippage occur
when DNA polymerase temporarily detaches from the template strand in regions with repetitive sequences.
What is the consequence of strand slippage
can lead to mutations such as insertion, deletion, in repetitive DNA sequences, causing a frameshift mutation.
What is depurination
removal of a and g from the backbone of DNA
deamination
removal of amino groups such as guanine, cytosine, and adenine
base excision repair
fixes single damaged bases
mismatch repair
corrects mismatch repairs or fixes small insertions/deletions occurring during DNA replication
why is transletion DNA synthesis highly error prone
The polymerase used lacks proofreading and intrinsically error prone
Non-homologous end joining
rapid, error-prone repairing pathway that directly liagtes broken DNA ends, often resulting in insertion or deletion
Synthesis-dependent strand annealing
more accurate, homology-directed repair pathway that uses a homologous template to synthesize new DNA
Terminal inverted repeats
identical sequences at the end of the DNA molecule in opposite orientation
Flanking direct repeats
identical sequences at the ends of mobile genetics but are in the same orientation
Somatic mutations
found in non-reproductive cells, after conception, not passed down genetically, affects a singular individual
Germline mutations
found in reproductive cells, during conception, can be passed down genetically
Transition
more common, change of base with the same base
trans version
substitution of base with a different base
nonsense mutation
creates a premature stop codon
What does the fluctuation test tell us about mutations
it tells us that they are random and that they don’t happen due to the presence of an selective agent
Do beneficial mutations arise in response to environmental pressures or randomly
Randomly
