Introduction to mutations
What is a mutation?
heritable change in genome
True or False: Bacteria cannot transfer DNA.
FALSE
Wild-type strains are isolated from where?
nature
True or False: selectable mutations confer an advantage
TRUE (ex. antibiotic resistance)
What is a mutation that causes a change in only one base pair?
point mutation
What is a mutant?
an organism carrying a mutation
What type of bacterial DNA transfer takes place with the use of a phage?
transduction
What is a mutant?
a cell or virus derived from the wild-type strain that carries a nucleotide sequence (genotype change)
True or False: Nonselectable mutations confer an advantage.
FALSE, even though they may lead to a phenotypic change it requires laborious, time consuming screening
Spontaneous mutations
What is horizontal gene transfer?
genetic exchange that can combine and accumulate multiple changes or transfer new genes
What type of DNA transfer takes place with the formation of a bridge?
conjugation
True or False: Phenotypes are ALWAYS altered when making mutants.
FALSE
Which is preferred selection or screening?
Selection, easier to see mutant
What type of mutations are caused environmentally or deliberately?
Induced mutations
What two things fuel evolution?
mutations and genetic exchange
What type of DNA takes place with uptake of free DNA from the environment?
Transformation
How is the phenotype change of a mutant designated?
Capital letter and two lowercase (ex. His+)
Auxotrophs typically have a what type of requirement compared to a prototroph?
nutritional environment (ex. His+ or His-)
What type of growth accumulates mutations quickly in prokaryotes?
exponential growth
Transformation takes place with the use of ____ containing DNA for a cell to uptake free DNA.
vesicles
How is the genotype of a mutant designated?
three lower case then capital letter (ex. hisC)
What can you have as a control when screening for nutritional auxotrophs?
complete medium sample for all colonies to grow
What are the three types of base-pair substitutions?
missense, nonsense, and silent mutations