Recombination Flashcards
In mitosis, homologous double strand break repair preferentially utilizes the _______ chromatid as repair template and exhibits a bias toward _____ recombination.
sister, noncrossover
in meiosis, homologous recombination preferentially utilizes the _____ chromatid as repair template and generates _____ recombinants.
homologous, both crossover and noncrossover
In the Holliday model of genetic recombination:
regions of heteroduplex DNA are generated by branch migration of Holliday junctions
Recombination is initiated by a double strand break on one of the participating chromatids in what model?
DSBR model of genetic recombination
The broken ends are extensively resected to create lengthy single strand regions in what model?
DSBR
following transfer of 3’ ends to form D loops, synthesis of new DNA from the 3’ ends is required to repair the gaps in what model?
DSBR
regions of heteroduplex DNA are generated by branch migration of Holliday junctions in what model?
DSBR
resolution of double Holliday junctions is biased so that only crossover products are generated in what model?
DSBR
enzyme that has both DNA helicase activity and single-strand endonuclease activity
RecBCD enzyme
A linear duplex molecule and a single strand circular molecule that is identical to one of the strands of the duplex can or cannot be paired with RecA?
can
a circular duplex molecule and a linear single strand molecule that is identical to one of the strands of the duplex can or cannot be paired by RecA?
can
Two identical circular duplex molecules, one of which contains a short gap in one strand can or cannot be paired by RecA?
can
Two identical circular duplex molecules, one of which contains a nick in one strand can or cannot be paired by RecA?
cannot
A full-length duplex chromosome ( could be millions of base pairs) and a 20 base single strand oligonucleotide that matches a 20 base stretch of one strand of the chromosome can or cannot be paired by RecA?
can
What kind of filaments are about 1.5 times as long as naked DNA, require single-strand DNA to initiate, are helicases consisting of about six ___ monomers per helical turn, contain binding sites for two DNA molecules?
RecA filaments
Holliday junctions are recognized and bound by:
RuvC and RuvA
Holliday junctions are generated by the enzymatic activity of:
RecA
Holliday junctions are cleaved by the enzymatic activity of:
RuvC
What is the doughnut shaped hexamer with ATPase activity which can rotate a DNA duplex and pull it through its central pore?
RuvB
In meiotic recombination, the enzyme responsible for inducing double strand breaks.
Spo11
In meiotic recombination, the enzyme responsible for resecting double strand breaks and generating long single-strand ends.
MRX
In meiotic recombination, the enzymes responsible for pairing and strand transfer are:
DMC1 and Rad51
What enzymes are involved in the meiotic SDSA pathway?
MRX, DMC1, Rad51, Spo11
SDSA pathway is thought to be important for generating non-crossover recombinants in:
mitosis and meiosis
What happens when DNA polymerases encounter a nick in the template strand?
DNA replication pauses adjacent to the nick, creating a DSB. Recombination enzymes such as Rad51 are recruited and DSBR restores the replication fork.
True or false: In meiotic recombination, gene conversion can result either from mismatch repair of heteroduplexes, or from extension of 3’ ends after D-loop formation
True
True/False: The SDSA pathway yields gene conversions but not crossovers whereas the DSBR pathway yields both gene conversions and crossovers
True
True/ False: In DSBR pathway, one of the two participating chromatids is unaltered by the recombination event, whereas in the SDSA pathway, in general, both participating chromatids are altered by the recombination event.
False
In gene conversion, a pair of alleles segregates at an unequal ratio, such as 3:1, 1:3, 5:3, or 3:5
True
Non-mendelian segregation of alleles is a hallmark of genetic recombination
True
