Mutation and Repair

Question 1

Skipped strand Mispairing

Answer 1

During DNA replication newly synthesized DNA containing repetitive sequences can misalign with template

Mispairing can occur on:
1. Newly synthesized strand
2. Template strand

***Mispairing is a mistake that can happen every time DNA repeats

Question 2

Mispairing on Newly sythesized strands

Answer 2

Repetative regions in new strand can align with themselves instead of the temple – creates a bubble in dsDNA

Occurs if the same template region is repeated two times

Result: Get expansion in number of repeated sequences in the newly synthesized strands

Question 3

What happens after new misaligned dsDNA

Answer 3

New dsDNA undergoes second round of DNA replication – NOW both strands act as template for DNA synthesis

One strand – n = 6 repeats –> Now a template and DNA polymerase will make 6 repeats

New strand – n = 8 repeats because of mispairing during replication –> If replicated then the new DNA will have 8 repeats

Question 4

Expansion vs. Contraction

Answer 4

Expansion is more common than contraction

Contraction = lose repeats –> Occurs if misalign template

Expansion = get more repeats –> Occurs if misalign new sythesized DNA

Question 5

Mispairing in Template

Answer 5

Mispairing can cause bubble in template = DNA polymerase can’t read part of the templaye (won’t read the part in the bubble

Result: Contraction – Newly synthesized DNA has fewer repeats

***In another round of replication = can get shorter track of repeats

Question 6

What does expansion/contraction explain

Answer 6

Nucleotide repeat expansion/contraction = epxlains how many short polymorphic sequences in genome are provided

Question 7

Polymorphic sequences

Answer 7

Sequence that has different forms/alleles in different individuals

Question 8

Where do most nucleotide repeats occur

Answer 8

Most of the time nucleotide repeats occur in regions that don’t have genes = have little consequence on phenotype

Issue: Nucleotide repeats can occur in genes –> interfere with transcription/translation or protein function
- Repeats can occur in different regions of gene

Question 9

Use of repeats

Answer 9

Used as molecular markers in lineage studying

Question 10

Class of disorders from repeats

Answer 10

Trinucleotide repeat disorders –> caused by expansion of 3 BP repeats

Image:
If in coding sequence = get extra coding = get extra Amino Acids

If in introns = affects splicing = translation is affected

Question 11

Huntingtons disease

Answer 11

Trinucelotide repeat disorder
Autosomal Dominant
Caused by Expansion of CAG sequence in HTT gene
- CAG = codon for Glutamine
Poly Q repeat
Abnormal HTT protein –> Leads to cell death
Symptons begin between 30 - 50 – Include Mood swings + Insteady Gait + Jerky Body movelments + Speech Loss + Dementia + Death

***Has varaible penetrance

Question 12

Abnormality in Huntingtons

Answer 12

Normal – 5 - 35 HTT repeats (HTT gene has a small number of repeats = no symptoms)

Pathogenic – 36 - 250 Repeats
- Have varaible penetrace in the lower range

Question 13

What determins huntingtons symptoms

Answer 13

Symtoms are correlated with the # of repeats
- Less repeats = may not have symtons = varaible penetance

More repeats = can develope more + More severes symtomes + might show symtoms earlier
- More repeats = more likley to have slippage = start having symtoms younger down pedigree + more severe

Question 14

Huntington protein

Answer 14

Works in nueron in brain –> Expansion of CAG repeats = increase the number of codons for Glutamine (Glutamine = Q) –> Have Poly Q repeat
- Expansion of Glutamine resdiues = causes protein to misfold = brain cell death

Question 15

Gene Anticipation

Answer 15

Describes the phenomon when a genetic disorder is passed on to the next generation and the symtoms become apparaent at an ealier age in each generation
- Individuals with lower numbers of repeats may not show symtoms or they may show them at an older age – with each generation there have been more opertunities for DNA replication and slipped strand pairing – leading to offsrping with more repeats + more sever symptomes + earlier onset
- Each time you replicate = increase the chance you will make a mistake = deeper in pedigree = more likley to make mistakes
- Slippage does NOT have to hapen each time but can
- More repeats = more likley to have slippage = start having symtoms younger down pedigree + more severe

Example – Huntington
Image – Start with 55 reaptes –> passes reapeats to half of kids (have slippage – get more repeats –> passed 85 and 75 repeats to kids) –> Kidds passed to kidds (Passed 90 and 250 – big expansion)
- Some individuals with repeats do not have symptoms BUT pass to kids that have expansions and have huntingtons
- Indiviuals with repeats pass to half their kids
- Pass down mutatnt allele BUT they often have expansion events = increase in number of repeats in kids with mutant allele

Question 16

Where does Insulin come from

Answer 16

Insulin = produced by the pancreus

Diabetics = mutations in production of insulin –> they need to inject insulin

Human insulin can be made in E.coli + Yeast + human cells lines –> Have a plasmid (that can replicate itself) –> In the plasmid have heme fpr human insulin –> The cells make insulin – Can isolate insulin from the cells
- The E.coli are now considered recombinant organisms because they have DNA from other organsim

Question 17

What cells can be used to make insulin

Answer 17

E. Coli + Yeast + Human Cell lines

Question 18

Use of PCR + Inulin + Plasmids

Answer 18

Use PCR to amplify the insulin gene from human DNA THEN clone it into a bacterial Plasmid

Overall – Insert the human insulin gene –> Amplify the gene then clone into bacteria

Steps:
Cut plasmid to produce sticky ends–> Insert Insulin gene – Glue the sticky ends together –> Put recombinant plasmid in E.Coli

Question 19

Answer 19

dATP – Primer is extended 5’ –> 3’ – nucleotides get added to 3’ end of the primer

Question 20

What does DNA polymerase need

Answer 20

Needs dsDNA and 3’ end –> Adds nucleotides to 3’ end

Question 21

Answer 21

ANSWER: B and C

AT C – Goes 5’ –> 3’

AT B – Goes 5’ –> 3’

D = not right because would be 3’ - 5’ (5’ - 3’ would be awauy from yellow)
A = not right because 5’ - 3’ would be away from yellow

Question 22

Fowards vs. Reverse primer

Answer 22

Both go inward towrds the sequnece you are amplifying
- Fowards = Comes from left (goes right)
- Reverse = Comes from right (Goes left)

Fowards = Identical to the 5’ - 3’ template strand (Identical to the top strand)
- Binds to bottom strand
Reverse = Identical to the 3’-5’ strand but in reverse = reverse compliment of the 5’ - 3’ strand (reverse complement of top strand)
- Reverse = binds to top strand

Question 23

Example Reverse and foward primer

Answer 23

Question 24

Number of strands after X number of PCR cycle

Answer 24

After 1 cyles – Have 2 strands of dsDNA (One with orginal + One with new strand)

After 2 cycles – Have 4 strands
- One of the strand

Question 25

Length of building things on orginal template

Answer 25

Anything being built on orginal template = Longer than desired product BUT it is ok because these get diluted - Because primer binds to ONE strand = will go on forcever on other side Doesn't happen from newly synthesized because dsDNA of ONLY newly synethesied = only stops at where the primers marked it = doesn't go on forever - Does not go on forever because stops because the newly synthesized are from the primer end = won't go on forever

Question 26

Restriction enzymes

Answer 26

Cut DNA at specific sequences -- bind to specific sequence and cute DNA at that site - Bind to dsDNA at specific sequences and cit the DNA leaving single stranded overhangs WHEN they cut = they cut so there is overhang - Cut = get 2 peices + have sticky overhang

Question 27

Why have overhang

Answer 27

It is hard to stick 2 blunt ended peices of DNA together -- hard to get blunt ends to stick together --> overhamgs are more likley to stick together = RE cut so have sticky ends If we add a restriction enzyme recognition seqneces to the end of PCR product we will have a much easier time getting teh PCR product to stick in the plasmid

Question 28

RE + PCR

Answer 28

If we add a restriction enzyme recognition seqneces to the end of PCR product we will have a much easier time getting teh PCR product to stick in the plasmid - Restiction enzyme is used to cut at the end of the gene = get sticky ends = easy to get to stick together with plasmid

Question 29

Different restriction enzymes

Answer 29

Different restriction enzymes recognize and cleave different sequnces - All cut in different places Some = produce sticky ends and some produce blunt ends - Usually use ones that make sticky ends

Question 30

Answer 30

Example application of question -- if you wanted to add sticky ends at PCR = wanted to add in extra DNA that does not match template to get places for RE to cut Answer: Add to the 5' end of primer because DNA polymerase adds DNA to 3' end of primer - DNA polymerase adds nucleotoides to the 3' end IF have a sequence that does not match template THEN DNA polymerase might not be able to add Adding DNA that is not on template -- add to the 5' end of the primer -- IF you have enough DNA at the 3' end of the template -- DNA polymerase can sit on the dsDNA and add nucleotides to it IF you do not give polymerase enough dsDNA eher it can add nucleotodes then it will not add nucleotides -- SO you add DNA at the tail end of primer because as long as have enough primer to tenplate (enough dsDNA for polymerase to hold onto) = can get DNA polymerase to add - Add to the 5' end to give Polymerase enough dsDNA to be able to hold onto to be able to add more nucleotides

Question 31

Answer 31

ANSWER: Ligase Ligase = smoothers kinks after DNA replication - Can glue PCR product into plasmid

Question 32

Recombinant insulin plasmid (process image)

Answer 32

PCR --> Restriction Enzymes --> Ligase --> Ends get recombinant plasmid

Question 33

PCR + restcition enzymes

Answer 33

PCR adds the restriction enzyme binding site THEN you are able to add the restriction enzyme ***Part of primer is still there after add restriction enzyme

Question 34

DNA repair take home message

Answer 34

1. DNA mutations occur during DNA replication and DNA damage -- mistakes are a fact of life - Every time replicate DNA introduce mistakes 2. Mutations in DNA and repair pathways can lead to disease (Especially cancers) OR beneficial evolutionary changes

Question 35

Halmark of cancers

Answer 35

Mutations

Question 36

How many DNA repair pathways exist

Answer 36

At least 6 --> There is cross talk between these repair pathways Understanding DNA repair mechanisms is an active area of research

Question 37

What do gene editting technologies rely on

Answer 37

Gene editting technologies (SUCH AS CRISPR) rely on DNA repair pathways

Question 38

Are all mutations bad?

Answer 38

NO -- NOT all mutations are bad 1. Mutations are how we learn how cells workd 2. Can be used for evolution

Question 39

Mutations between parents and offspring

Answer 39

There are 100 nucleotide mutations between patents and offspring due to mistakes in DNA replications -- MINOR source of mutations - Mistakes due to DNA polymerase

Question 40

Mutations due to DNA polymerase

Answer 40

Sometimes DNA polymerase makes mistakes - Minor source of mutations MOST enzymes do one job BUT DNA polyymerase does more than one job -- It makes DNA + senses mistakes + Has EXOnucleoase activity = NOT a major source of mutations

Question 41

DNA polymerase jobs

Answer 41

MOST enzymes do one job BUT DNA polyymerase does more than one job -- It makes DNA + senses mistakes + Has EXOnucleoase activity - Multifunctional enzyme --> Adds nucleotides + Senses probelm + Cleaves probelm off

Question 42

DNA Polymerase correction

Answer 42

Proof reads + Exonuclease activity -- Polymerase has repair mechansims -- looks to see if the nucleotide is right -- IF there is a mistake it can move to another domain of the enzyme --> can cut off mistake --> Add new nucelotides Proofreading -- DNA polymerase inspects each nucleotide that it inserts Exonuclease activity -- IF Polymerase senses an error it will remove that nucleotide and try again ***Sometimes errors get through

Question 43

How does DNA polymerase proofread

Answer 43

Looks to see if the helix forms correctley

Question 44

Exonucelase acivity

Answer 44

Removing nucleotides (FROM END OF DNA)

Question 45

Error prone regions

Answer 45

Repetitive regions OFTEN varaible region because DNA polymerase is prone to making mistakes

Question 46

Errors in repetative regions

Answer 46

Can occur if DNA slips -- expands and contracts DNA Error = slippage --> Slippage gets incorporated into the next generation In Nasacnt DNA -- the new ssDNA can bind to instelf --> form a hairpun loop (stem loop) - New DNA binds to itself NOT The template - Result: Expands DNA - region binds to complementray on same ssDNA --> Get loop of DNA -- WHEN that DNA is used again it will become a template and NOW has extra nucelotides

Question 47

Trinucleotode disorders

Answer 47

1. Huntingtons Disease 2. Fragile X Syndrome 3. Freidrich's Ataxis Caused because region is being expanded

Question 48

How many groups are added in trinucelotide repeat regions

Answer 48

Usually groups of three are added

Question 49

Expansion Vs. Contraction

Answer 49

You can get slippage in the new strand or template strand Expansion = because of Newly synthesized DNA Contraction = because of template (lose repeats) Expansion = MORE COMMON

Question 50

Where can slippage/expansion + contraction occur

Answer 50

Can occur in coding or non-coding regions --> Can cause phenotype or not - Can cause disease

Question 51

Is DNA polymerase more likley to make mistakes in genes than non-coding regions

Answer 51

NO -- DNA polymerase is NOT more likley to make mistakes in genes than non-coding regions -- Polymerase doesn't care what DNA is being replicated

Question 52

UV Light + DNA

Answer 52

UV light = causes distortions to DNA helix + Interferes with DNA replication + Gene expressions Occurs when have 2 T next to each other --> When UV light hits = causes covalent bonds between aromatic rings Causes BULGE in DNA

Question 53

Suncreen

Answer 53

Zinc Oxide -- reflects UV Light Oxybenzone -- Obsorbes UV light --> Prevents from hitting DNA To be effective need sheild --> Most effeicient = out a TON on ***Wear suncreen

Question 54

Main sources of mutations

Answer 54

1. UV light 2. ROS

Question 55

ROS

Answer 55

Reactice oxygen species --> Natural byproduct of mitocondrial Pxydative Phosphorylation (because the electrons go other places -- the electrons that espace react with H2O or O2 --> get radicals --> radicals damage DNA - INflamation can increase mitocondrial ROS production DNA damage by ROS: 1. Modified bases (Example -- get C --> U) 2. Nicks in phosphate backbone -- get breaks in backbone 3. Double strand breaks -- get breaks in backbone (Very common) - Big problem -- lose of chunk of DNA

Question 56

Double strand breaks

Answer 56

Very common -- 10-50 every day Causes: 1. ROS 2. Ionizing radiation (UV) 3. Chemicals 4. Physical stress on chromosomes 5. Errors in DNA repair

Question 57

Antixidants

Answer 57

ROS = a signalling mocleule --> VERY important -- sometimes you want genes to be ready to be turned on -- ROS keeps them primed and ready to go BUT wants low levels of ROS Don't overload systems with antioxidants (need them to keep genes primed)

Question 58

DNA repair pathways

Answer 58

1. Mismatch repair (MMR) -- cut out a bunch of nucleptides --> refill area --> Seal nicks 2. Direct Repair -- If have damage to nucleotide -- gets rid of modification 3. Nucelotide Excision Repair (NER) -- cut out a bunch of nucleptides --> refill area --> Seal nicks 4. Base Excision Repair (BER) -- Have nucleotide you don't want --> cut it out --> Put new nucelotide in --> Seal Nick 5. Non-homologous end joining (NHEJ) -- when have double strand breaks --> takes 2 blunt ends and glues together - If have overhang will fill over hang to get blunt ends 6. Homolgous recombination (HR) -- Use recombination to copy from other chromosome (copy what is on dad chromsome onto mom's chromosome)

Question 59

What happens when DNA is not repaired

Answer 59

When mistakes are not repaired = they result in permanent (sometimes heritable change) Mistakes in somatice = can cause cell to misfunction Mistakes in Germ line = passed on to next generation

Question 60

How doe NER and MMR sense Issues

Answer 60

Sense because of change in DNA shape

Question 61

Mismatch Repair in DNA replication

Answer 61

MMR proteins follow DNA polymerase during DNA replication to fix what DNA polymerase did not SOME MMR proteins bind to the replisome (bind to sliding clamps loader)

Question 62

Mismatch repair

Answer 62

Fixes Mismatches (Example G-T) Process: 1. A mismatch on the new strand is first detected 2. Restrictino enzymes cut the DNA -- EXOnucleoases resect the wrong nucleotides and a few more -- leaving a gap 3. DNA polymerase resythesizes the DNA in the gap 4. Ligases seal the gap to remove the nick

Question 63

How do MMR enzymes know which strand is new and which strand is old?

Answer 63

Old DNA = often methylated (has CH3 groups) --> MMR proteins use methylation state to decide which is the correct template strand IMAGE = knows to cut strand with G because methylation patterns

Question 64

Nucleotide excision repair

Answer 64

Overall: recognize bulges and misshapen DNA structure - Fixing multiple bases NOT just one Process: A segment of the DNA containing the misshapen is removed THEN refilled

Question 65

What does direct repair fix

Answer 65

Chemical modification on nucleotide bases Chemical modifications can occur on nucleotide bases --> these modifications can interfere with DNA replication/expression Direct repair enzymes recognize and remove these medications

Question 66

Direct repair

Answer 66

Fixes chemical modification on nucleotide bases --> Enzymes recignize + remove these enzymes NOTE -- DOES NOT INTERUOPT THE PHOSPHATE BACKBONE

Question 67

Direct repair enzymes

Answer 67

There are many direct repair enzymes that each recognize a different type of modification

Question 68

Base Excision repair

Answer 68

Overall: Fixes mismatches or chemical modifications to a base by removing and replacing a SINGLE nucleotide ONLY 1 nucleotide is removed and replaces CUTS AND REPAIRS PHOSPHATE BACKBONE

Question 69

BER enzymes

Answer 69

1. Glycosylases -- recognize specific base pairing mistakes and remove the base leaving a hole There are >20 different glycosylases in the cells 2. AP ENDOnucleoases -- remove the sugar phosphate backbone 3. DNA polymerase adds a new nucleotide 4. Ligase seals the nick

Question 70

Issue in Base Excision Repair

Answer 70

BER is not always good at determining which nucleotide is the correct nucleotide = sometimes the fix leads to a permanent mutation ***New permanent mutation can be introduced

Question 71

What does NHEJ repair

Answer 71

Double strand breaks

Question 72

What can double strand breaks make

Answer 72

ds breaks can produce different types of overhands 1. 5' overhangs 2. 3' overhans 3. 5' and 3' overhangs

Question 73

NHEJ

Answer 73

Overall: Fixes double strand breaks Process: NHEJ fills in or removes overhangs to produce blunt ends --> THEN NHEJ will ligate the blunt ends together Enzymes = Polymerases + Nucleases (exonuclease) + Ligases

Question 74

Issue in NHEJ

Answer 74

the dsDNA breaks is repaired BUT there are always INDELS (Insertions or deletions)

Question 75

Homologous repair

Answer 75

Overall: Fix double strand breaks Process: 1. resect a larger portion of DNA 2. Using homologous chromosome as a template for new DNA synthesis 3. The repaired chromosome now contains a sequence that is identical to homologous chromosome IMAGE -- A part of the blue chromosome now contains a copy of the sequence from the red chromosome ***ALSO called Homologous direct repair

Question 76

What can fix double strand breaks

Answer 76

1. NHEJ 2. Homologous repair

Question 77

Potential result of Homologous recombination

Answer 77

Can lead to LOSS of heterozygosity A part of the blue chromosome now contains a copy of the sequence from the red chromosome -- leads to loss of blue chromosome = loss of heterozygosity

Question 78

What can occur during homologous recombination

Answer 78

Crossovers can occur = reorganizes maternal and paternal alleles --> Form of mitotic recombination

Question 79

Xeroderma pigmentosum

Answer 79

Indiviuals are particular sensitive to sunlight

Question 80

What repair pathways is likley damaged in Xeroderma pigmentosum

Answer 80

Nucleotide Excision repair -- BECAUSE NER fixes bulges (UV light causes bulges) -- cuts bulge --> Synthesize DNA --> ligates Causes by 1 of 7 enzymes mutated in NER --> get a bulge from the dimer -- bulge is what NER recognizes and fixes

Question 81

What type of enzyme cuts damaged DNA

Answer 81

Endo and exo nucleases acivity Endo --> cuts DNA in the middle of the strand (cut in middle of chain) Exo --> Cuts at the end of DNA chain (starts at the end of DNA chain and cits away nucleotides)

Question 82

What enzyme makes blunt ends in NHEJ

Answer 82

Exonuclease -- at break = goes from end = EXO THEN to fill in = use polymerase Exonuclase + polymerase = part of NHEJ

Question 83

Deamination

Answer 83

Spontaneous deamination of Cystine produces Uracil ***High protein diets can also lead to deamination

Question 84

What repair pathway fixes deamination

Answer 84

Base Excision Repair --> Have glycosylases -- each one recongnizes a certain mismatch - Glycosylases = makes a hole BER --> Glycosylases = takes out one base -- makes a hole --> Another enzyme sees hole --> takes out backbone --> polymerase fills in nucleotide in hole --> Ligate smooths gaps - To cut nucleotide backbone = need endonuclease (because in middle) Can't have direct repair or mismatch repair --> Choose BER first but if mismatch finds it it will do it -- can have overlap

Question 85

Inversions

Answer 85

When regions of chromosome are reordered -- often the result of mistake in DNA repair

Question 86

What does NHEJ always produce

Answer 86

1. NHEJ = produces indels --> almost never get the same DNA (Always have some bases added or removed) - If chews away DNA = get deletion -- can have deletion on one side and inseration on the other Can lead to different frames 2. Can get inversions -- if peice gers flipped and glued together inverted = get inversion

Question 87

What repair pathway is making a mistake in inversions

Answer 87

NHEJ OR Homologous recombination (More so NHEJ) NHEJ = finds ends of double strand break and makes blunt ends --> Need the 1st chrosmome to be broken -- Ends don't need to match = can get inversion - double strand break makes overhangs -- NHEJ = makes blunt ends --> fills in overhang of exonuclease chews ends up

Question 88

Pericentric vs. Paracentric inversion

Answer 88

Pericentric = around centromere Paracentric = only on one side of centromere -- on one arm of a centromere

Question 89

Affect of inversions

Answer 89

Most often they do not alter phenotypes BUT may alter gebe regulation - because most of the genome is non-coding - Regulatpry region might not be affected often = no affect in inversion

Question 90

Position effect in inversions

Answer 90

When gene regulation is alterted due to inversion or transolation Inversion can have an affect if interupts a gene or a gene regulatory region - If affects gene regulatory region = gene is there but not being turned on correctly

Question 91

Potential affect of inversions

Answer 91

Inversions can affect fertility -- inversions often lead to gametes that are not viable = reduced fertility IF have inversion = homologous chrosomes can't recombine well --> can get a loop (loop around to match --> THEN they align with a loop in the chromosome and then recombination happens END - get a gamete with extra/missing genes - Get deletions + duplications in offspring - Not an issue in mom/dad (inversion does not affect them) BUT get gametes that might not be viable 2nd affect -- can get recombination that produces dicentric chromosome -- has 2 centromeres - The dicentric chromosome = doesn't work in cell division --> chromosome will break

Question 92

Mistakes in Homologous Recombination + NHEJ

Answer 92

Can lead to chromosomal rearangments Example -- 1. Translocation 2. Non-allelic homologous recombination

Question 93

Translocations

Answer 93

Cut and exchange --> No cost or gains JUST peice from one chromosome going to other chromosome - Was on one chromosome and is put on the other chromsome

Question 94

Familial downsyndrome

Answer 94

Caused by transolaction that fuses chromosome 14 and 21 --> get 3 copies of chromsome 21 = downs syndrome - Caused by translocation Have chromosome 21 and 1 area of chromsome 21 and have chromsome 14 --> fuse together --> the indiviuals is normal but 3 chromosome can't line up correctly --> have 3 possibilities for gametes (IMAGE) Can get 2 copies of 14 or 1 copy of 14 or 3 copies of 14 --> ALL are not viable - Carrier - has reduced fertility and 1/3 of kids will have downs syndrome - Carrier = phenotypically normal

Question 95

Answer 95

Weird that the individual got liver disease because they are Bb When sequence the person -- we see they are bb What happened -- they had homologous recombination --> had a ds break and fixed it by homologous recombination --> used the other chromsome as a template for repair (coped sequence from other chromome) - End = got rid of B alleles -- fixed double strand break by copying other chrosmome -- THEN they became homozygous bb = got liver disease - b is copied in place of B

Question 96

Non-allelic homologous recombination

Answer 96

Sometimes homolgous recombination can occur between the "wrong" repetative sequneces -- results in deletions and duplications (CNVs) - Not recombing at the right spot

Question 97

Simple vs. Reciprical translocations

Answer 97

Question 98

Effect of translocations

Answer 98

If the translation is balanced (no genes are lost or gained) = there is typically no effect on phenotype BUT there can be effects in offspring

Question 99

Foward primer

Answer 99

Binds to 3' strand Complementary to 3' strand = identical to 5' strand

Question 100

Foward primer

Answer 100

Binds to 3' strand Complementary to 3' strand = identical to 5' strand

Question 101

Reverse primer

Answer 101

Bind to 5' strand Matched the reverse of the 3' strand -- reverse complement of 5' strand

Question 102

Microsatilites

Answer 102

Human genome contains 50,000 - 100,000 dinucleotide microsatilites Microsatolites analysis using PCR is used for forensics + Paternity testing + cancer diagnosis + linkage studies