Chapter 11 recombination Flashcards
_______ is the exchange of genetic material between homologous DNA molecules
homologous recombination
In bacteria, and similarly in archaea, homologous recombination occurs during _______ and, as a consequence of double-strand break repair
conjugation
In eukaryotes, homologous recombination occurs during _______
prophase I of meiosis
the _______ pathway is the system of homologous recombination in bacteria
RecBCD
What is the process of the RecBCD pathway of recombination? (3)
1) Rec A protein binds to double stranded break
2) Rec BCD attatches leading to single strand invasion and D loop formation
3) Ruv AB and Ruv C bind and complete recombination
What proteins are needed to carry out double stranded break model of meiotic recombination part 1?
1) Spo11
2) Mrx and Exol
3) Rad51 and Dmc1
What is the process of double-stranded break model of meiotic recombination? part 1
1) Spo11 generates an asymmetric double-strand cut in one of the chromatids
2) Mrx and Exol digest single strands
3) Rad51 and Dmc1 facilitate strand invasion and D loop formation
4) Holliday junction created
What proteins are needed to carry out double stranded break model of meiotic recombination part 2?
1) Rad52
2) Rad 59
3) DNA polymerase
4) Ligase
What is the process of double-stranded break model of meiotic recombination? part 2
1) Rad52 and Rad59 assist DNA synthesis of the invading strand
2) the 3’ end of the invading stand joins to the 5’ end of its original chromatid by ligation
3) non-sister chromatids are now connected by double Holliday junctions
A _______ is double-stranded DNA formed from single-stranded pieces of DNA of different homologs
heteroduplex
Holliday Junction Resolution can occur two ways:
1) Same sense resolution
2) opposite sense resolution
In _______ two N/S cuts or two E/W cuts occur and DNA outside the flanking markers to not recombine
same sense resolution
in _______ 1 N/S cut and 1 E/W cut occurs and results in major changes in chromosome segments, ends swap
opposite sense resolution
Which is more common, same sense or opposite sense resolution?
opposite sense
_______ are DNA sequences that can move within the genome by an enzyme-driven process
transposable genetic elements
transposable genetic elements are moved within the genome by _______
transposition
What are the two ways that transposable genetic elements move?
1) excision
2) duplication
A transposable element can cause a mutation if it inserts into a wild-type allele and disrupts its function, this is called _______
insertional inactivation
What are the two elements that all transposable elements have in common?
1) terminal inverted repeats
2) flanking direct repeats
What is the process of transposition?
1) staggered cuts are made by transposase
2) double-stranded transposable element is inserted into the new site
3) DNA is replicated to fill single-stranded gaps
_______ transpose as DNA sequences and may be replicative or non-replicative
DNA transposons
________ are composed of DNA but transpose through an RNA intermediate
retrotransposons
the RNA of a retrotransposon is copied back into DNA by _______
reverse trancriptase
_______ excises a transposable element from one position and inserts it into a new location
non-replicative transposition
- cut and paste
______ are simple transposable elements containing terminal inverted repeats surrounding a gene encoding transposase
insertion sequences
_______ carry a transposase gene, two flanking IS elements, and one or more additional genes
composite transposons
_______ carry a transposase gene, and one or more additional genes but lack IS elements
non-composite transposons
Nearly _______ of the human genome is composed of transposable DNA
half
_______ infect eukaryotic cells and have genomes composed of single-stranded RNA
retroviruses
The gene(s) carried on retrotransposons are flanked by _______
long terminal repeats
the viral genes _______ and _______, encoded by the integrated virus, are needed to produce new retroviral particles: _______ encodes reverse transcriptase
gag
env
pol
Many types of _______ are found in yeast; these can cause insertional mutations
ty retrotransposons
multiple forms of _______ elements are found in the drosophilia genome
copia
_______ and _______ are relatively abundant and can cause mutation in humans
Long Interspersed elements (LINEs)
Short Interspersed elements (SINEs)
_______ are particularly common LINEs
L1 Elements
_______ are the most common of the SINEs and actively generate mutation
Alu Elements
