Horizontal Gene Transfer and CRISPR/Cas Flashcards
Mutation
Heritable change in DNA sequence
Alleles
Alternate forms of genes
Mutation can give rise to new ____.
Phenotypes
Vertical gene transfer: what is it, what domain of life can use it
Sexual reproduction: new combinations of genes arise when gates from parents fuse
Eukarya
How do bacteria and archaea generate genetic variability without sexual reproduction?
Horizontal gene transfer
Horizontal gene transfer: how it works
Genes are transferred from one independent organism to another
3 mechanisms of horizontal gene transfer
Conjugation
Transduction
Transformation
Conjugation
DNA transfer through direct cell-cell contact
What 2 things does conjugation require?
Pili
Plasmids
Conjugation is the major mode of spreading what kind of genes?
Antibiotic resistance
Plasmids: single or double stranded DNA? Linear or circular?
Double stranded, circular
Do plasmids rely on chromosomes, or are they separate?
Separate/ extrachromosomal
Plasmids carry genes that confer _____.
Advantage
Plasmids can be transferred by ______.
Conjugation
Plasmids are replicons. What does that mean?
They have their own ori
Episomes
Plasmids that exist with or without integrating into chromosome
Well-known example of conjugative plasmid: name and species that has it
F (fertility) factor
E. coli
Conjugation can also be referred to as _____.
Mating
Step 1 of conjugation
Pilus extension from donor (F+) to recipient (F-)
Step 2 of conjugation
Pilus retracts
F factor begins replication and transfer
Step 3 of conjugation
Plasmid-encoded endonuclease nicks one strand of F factor
F factor is replicated and transferred
Single strand enters recipient
Step 4 of conjugation
New complementary strand is made through rolling circle replication in both donor and recipient
Hfr cell: what does Hfr stand for?
High frequency of recombination
An Hfr cell does what with the F factor plasmid? What does this mean for gene transfer?
Integrates it into chromosome
Integrated F factor can also be excised out of chromosome, taking part of chromosome with it