Recombination Review Deck Flashcards Preview

CSF Block 5 > Recombination Review Deck > Flashcards

Flashcards in Recombination Review Deck Deck (22)
Loading flashcards...
1
Q

what is required for 2 DNA molecules to undergo homologous recombination?

A

they must share an extended region of nearly identical DNA

2
Q

what are the 2 “uses” of homologous recombination?

A

genetic variation

repair of damaged DNA

3
Q

what protein will enable DNA single strand to pair with homolog?

A

RecA protein

4
Q

what formation is unique to homologous recombination?

A

double holliday junction

5
Q

what are the 2 possible outcomes of homologous recombination?

A

crossing over- exchange large regions of DNA

no crossing over- only regions between holliday junctions are swapped

6
Q

what is gene conversion?

A

gene conversion is loss of 1 allele and gain of another (not same as crossing over)

7
Q

when does gene conversion occur?

A

when there is no crossing over, if there is repair of the small amount of distortion that occurs in the process

8
Q

8 steps in homologous recombination

A
  • homologs align
  • double stranded DNA break
  • RecA
  • strand invasion
  • strand elongation
  • holliday junctions
  • endonucleases cut at junctions
  • crossing over or no crossing over
9
Q

when does homologous recombination occur at the highest frequency?

A

meiosis

10
Q

describe site-specific recombination

A

occurs at a particular DNA sequence, extensive homology not required

11
Q

what enzymes guide site specific recombination?

A

recombinases

12
Q

what are the 2 important types of site specific recombination discussed?

A

horizontal gene transfer- MRSA

VDJ recombination

13
Q

what is VDJ recombination?

A

generation of antibody and T cell diversity in the immune response

14
Q

what enzymes/genes are involved with VDJ recombination? 4

A

VDJ recombinase
recombination activating gene 1/2 (RAG1/2)
recombination signal sequence (RSS)

15
Q

what is involved with DNA transposition?

A

short segments of mobile DNA with the capacity to move from one location to another

16
Q

3 classes of transposons

A
  • DNA transposons
  • retroviral transposons
  • non-retroviral transposons
17
Q

what enzyme is used by DNA transposons?

A

transposase

18
Q

what enzymes are used by retroviral transposons?

A

reverse transcriptase, integrase

19
Q

what enzyme are used by non-retroviral transposons?

A

reverse transcriptase, endonuclease

20
Q

what are examples of non-retroviral transposons?

A

LINEs, SINEs

21
Q

where can transposons insert?

A

middle of exon = non-functional protein
promoter = transcription activated
intron = no effect

22
Q

what type of transposition is assoc with hemophilia?

A

L1 LINE element in the gene for factor 8