Chap 12 - Gene Mutation

Front 1

Mutation Rate

Back 1

The number of times mutation alters a particular gene gene per replication cycle or per generation

Front 2

Base-pair Substitution Mutation

Back 2

The replacement of one nucleotide base pair by another

Front 3

Transition Mutation

Back 3

One purine replaces another, e.g. A replaces G

OR

One pyrimidine replaces another, e.g. T replaces C

Front 4

Transversion Mutation

Back 4

A pyrimidine is replaced by a purine, or vice-versa, e.g. A replaces C, or G replaces T

Front 5

Silent Mutation

Back 5

A base-pair substitution producing an mRNA codon specifying the same amino acid sequence as the wild-type mRNA

Front 6

Missense Mutation

Back 6

A base-pair substitution that results in an amino acid change to the protein

Front 7

Nonsense mutation

Back 7

A base-pair substitution that creates a stop codon in place of a codon specifying an amino acid

Front 8

Frameshift mutation

Back 8

Insert or deletion of one or more base pairs in the coding sequence resulting in the alteration of the reading frame of the resulting mRNA

Front 9

Regulatory Mutation

Back 9

Mutation in non-coding region of DNA

Front 10

Promoter Mutation

Back 10

Mutation that alters consensus sequence nucleotides and interferes with efficient transcription initiation

Front 11

Splicing Mutation

Back 11

A mutation altering the normal splicing pattern of a pre-mRNA

Front 12

Cryptic Splice Site Mutation

Back 12

A base-pair substitution that creates a new splice site, altering translation

Front 13

Forward Mutation

Back 13

Any mutation!

Front 14

Reversion / Reverse mutation

Back 14

Mutation that converts a mutant to a wild-type

Front 15

Intragenic reversion

Back 15

A reversion that occurs through mutation elsewhere in the same gene

Front 16

Spontaneous Mutation

Back 16

Uninduced mutation, usually produced through errors during DNA replication

Front 17

Tautomer

Back 17

Two forms of the same compound which differ by positions of a hydrogen atom

Front 18

Pyrimidine Dimer

Back 18

Covalent bond between two pyrimidines

Front 19

DNA Repair Mechanisms

Back 19

Mismatch Repair

Nucleotide Base Excision Repair

Nucleotide Excision Repair

Direct Repair of UV-Induced Photoproducts

UV Repair

Front 20

ATM

Back 20

Protein that senses DNA damage and induces production of p53

Front 21

p53

Back 21

Protein that controls cell cycle

Front 22

NHEJ

Back 22

Non-Homologous End Joining, an error-prone repair process in which damaged nucleotides are removed and blunt ends of strands are joined.

Front 23

SDSA / Synthesis-Dependent Strand Annealing

Back 23

Perfect repair of double-strand breaks after DNA replication, using the intact sister chromatid to repair the damaged one

Front 24

Homologous Recombination

Back 24

The exchange of genetic material between homologous molecules of DNA

Front 25

Holliday Model

Back 25

Model of meiotic recombination

Front 26

Spo11

Back 26

Protein that initiates meiotic recombination

Front 27

Meiotic Crossing Over & Double Holliday Junction Formation - 8 steps

Back 27

1. Spo11 creates double-strand break in on DNA duplex
2. Mrx digests some DNA creating single-strand segments
3. XRCC3 & Rad51c assemble strand-exchange nucleotide filaments
4. The strand-exchange filaments promote strand invasion
5. Strand invasion creates a D-loop and the first heteroduplex region
6. Strand extension by DNA polymerase displaces D loop DNA, which pairs with complementary single-stranded DNA to form the second heteroduplex region
7. Strand extension and ligation fills the single-stranded gap in the strand paired with D-loop DNA
   1. Double Holliday Junctions form after the nick is sealed

Front 28

East-West cut of Holliday junction produces . . .

Back 28

?? One possible pattern for resolving a Holliday Junction to separate homologous chromosomes before meiotic anaphase ??

Front 29

North-South cut of Holliday junction produces . . .

Back 29

?? One possible pattern for resolving a Holliday Junction to separate homologous chromosomes before meiotic anaphase ??

Front 30

Mismatch Repair

Back 30

DNA repair process that repairs non-complementary base pairs that occur through errant DNA replication or through nucleotide base modification, restoring normal complementary base pairing

Front 31

Deamination

Back 31

A DNA lesion resulting in the loss of an amino group from a nucleotide base

Front 32

Double-strand break repair

Back 32

Following phosphodiester bond breakage on both strands of a DNA duplex, a mechanism of DNA damage repair

Front 33

Induced Mutation

Back 33

Mutations generated by exposure to physical, chemical, or biological mutagens

Front 34

RecBCD Pathway

Back 34

3 Bacterial proteins that cut DNA and facilitate homologous recombination

Front 35

Displacement Loop (D loop)

Back 35

During DNA damage repair and homologous recombination, the displacement of a single-strand of DNA by strand invasion.

Front 36

Photoreactive repair

Back 36

A mechanism of DNA damage repair in bacteria that uses light in the visible part of the spectrum to provide the energy to remove the damage done by ultraviolet irradiation

Front 37

Translesion DNA synthesis

Back 37

Utilizing a bypass polymerase, a mechanism for replicating DNA in the presence of damage that blocks replication by the common polymerase

Front 38

Point Mutation

Back 38

A DNA lesion at a defined location. Usually either a base pair substitution or the insertion or deletion of a small number of base pairs

Front 39

Base Excision Repair

Back 39

DNA repair that excises a damaged nucleotide base and then replaces the entire nucleotide

Front 40

Photoproduct

Back 40

a DNA lesion produced by exposure to UV light

Front 41

Nucleotide Base Analog

Back 41

A compound with a size and shape that mimics a natural nucleotide base

Front 42

Bypass Polymerase

Back 42

A group of DNA polymerases that are unstable and synthesize short regions of DNA under conditions in which the main DNA polymerase is unable to function, such as when faced with DNA lesions that block replication.

AKA Translesion DNA Polymerase

Front 43

Strand Slippage

Back 43

A mutational event leading to increased or decreased numbers of repeating nucleotides in newly synthesized DNA. Caused by slippage of DNA polymerase on the template strand or slippage of the newly synthesized strand on DNA Polymerase

Front 44

Aberrant Ratio

Back 44

In fungi, a ratio of haploid spore genotypes within a single ascus indicating gene conversion

Front 45

Ames Test

Back 45

Lab method to determine whether a compound or one of its breakdown products is mutagenic

Front 46

Nucleotide Excision Repair

Back 46

DNA repair in which a segment of one strand containing damaged nucleotides is excised and replaced

Front 47

Bulky Adduct

Back 47

Large chemical groups added to nucleotides by alkylating agents

Front 48

Blotting (in gel electrophoresis)

Back 48

Transferring proteins or nucleic acids from an electrophoresis gel to a permanent membrane or filter

Front 49

Mutagen

Back 49

A chemical, physical or biological agent capable of damaging DNA and creating a mutation

Front 50

Holliday Junction

Back 50

A DNA structure that forms during meiotic recombination in which single strands are crossed over between nonsister chromatids of homologous chromosomes

Front 51

UV Repair

Back 51

DNA repair system that corrects lesions caused by exposure to ultraviolet irradiation

Front 52

Apurinic (AP) site

Back 52

The location of a nucleotide that has lost its purine base

Front 53

BRCA1-Associated Genome Surveillance Complex (BASC)

Back 53

Protein that surveys the genome for mutations at the G1 - to S-phase cell cycle checkpoint

Front 54

DNA Intercalating Agents

Back 54

Mutagenic compounds of a size and shape that allow them access to the space between nucleotide base pairs, distorting the DNA duplex and potentially causing insertion or deletion mutations

Front 55

Double Holliday Junction (DHJ)

Back 55

An intermediate structure temporarily connecting chromatids of homologous chromosomes that form during homologous recombination

Front 56

Suppressor Mutation

Back 56

A mutation whose effect is to reverse the effect of another mutation, restoring wild-type function

Front 57

Second-site Reversion

Back 57

A specific type of reversion taking place at a location separate from the site altered to generate the original mutation

Front 58

Gene Conversion

Back 58

Repair of mismatched (non-complementary) DNA nucleotides in heteroduplex DNA that forms during meiotic recombination. One allele is switched for another allele already in the genotype

Front 59

Strand Invasion

Back 59

During synthesis-dependent strand annealing and meiotic recombination, the entry of the 3' end of a displaced DNA into the intact sister chromatid

Front 60

Heteroduplex DNA

Back 60

A DNA duplex created during homologous recombination by combining complementary strands of DNA from non-sister chromatids.

Front 61

Homologous Recombination

Back 61

Exchange of genetic information between homologous DNA molecules