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Flashcards in DNA recombination Deck (19)
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1
Q

what is required for homologous recombination?

A

two DNA molecules must share extended regions of nearly identical nucleotide sequences

2
Q

what are the 2 main functions of homologous recombinations?

A

1- introduction of genetic variation

2- repair of damaged DNA

3
Q

when does homologous recombination occur with the highest frequency?

A

meiosis

4
Q

hat will facilitate the formation of double strand breaks in homologous recombination?

A

Spo11 and Mre11 nuclease complex

5
Q

what “facilitates” homologous recombination?

A

RecA

6
Q

what will prevent recombination between poorly matched sequences?

A

mismatch proof-reading machinery

7
Q

what is gene conversion?

A

loss of 1 allele and gain of another; there is always a small amount of distortion and if it is repaired, gene conversion will result

8
Q

what is site specific recombination?

A

involves genetic exchange at particular, short, DNA sequence

9
Q

what guides site specific recombination?

A

recombinases

10
Q

what is VDJ recombination?

A

mode of site specific recombination, joining of V and J DNA regions during the production of immunoglobulins and TCRs in immature B/T lymphs

11
Q

describe the process of VDJ recombination

A

VDJ recombinase is the collection of enzymes used
initial steps by RAG1 and RaG2 (recombinations activating gene)
enzymes recognize recombination signal sequence (RSS) and induce cleavage at the site

12
Q

what is DNA transposition?

A

movement of a short DNA segment from one location to another

13
Q

3 major classes of transposons

A

DNA transposons
retroviral transposons
non-retroviral transposons

14
Q

what enzymes is used in DNA transposons?

A

transposase

15
Q

what enzyme is used in retroviral retrotransposons?

A

reverse transcriptase, integrase

HIV

16
Q

what enzyme is used with non-retroviral retrotransposons?

A

reverse transcriptase and endonuclease

LINEs, SINEs

17
Q

what is the effect of a transposon in the middle of an exon?

A

non-functional product

18
Q

what is the effect of a transposon in the promoter/regulatory element?

A

transcription activation or suppression

19
Q

what is the effect of a transposon in an intron?

A

no effect