All DNA testing is based on

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Forensic DNA, DNA matching
All DNA testing is based on the observation that
every persons genome is different from everyone
elses
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Types of DNA Functional Single copy genes -
Otx Gene families similar genes at
multiple loci ie. actins, keratins,
histones Tandem gene family arrays
rRNA Non-coding functional sequences
telomeres, repeats (TTAGGG) at tips of
chromosomes
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Non-functional DNA sequences Highly repetitive
centromeric DNA DNA found in/near centromere
(but not involved with kinetochore attachment) VN
TRs 15-100 bp tandem repeats - number of
repeats is highly variable, - useful as DNA
fingerprints Transposed sequences RNA origin,
inserted in genome by retroviruses. Spacer
DNA what is left
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300-fold difference between the genome sizes of
yeast and mammals, but only a modest 4-5-fold
increase in overall gene number
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Functional Importance
Histones Tubulins Otx (Transcription
factors regulate gene expression) Alba wing
color polymorphism VNTR sequences
Rate of sequence evolution
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To identify differences, you can perform a
southern blot cut the DNA with a restriction
enzyme that recognizes and cuts specific
sequences, run the cut DNA on a gel, probe it
with a sequence that binds the VNTR
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(No Transcript)
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To identify differences, you can perform a
polymerase chain reaction, which requires much
less DNA. The reaction makes many copies of the
VNTR from a very small amount of DNA. It is The
method of choice in forensics
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The Polymerase Chain Reaction (PCR)
Suspects DNA
Conserved sequence
More DNA
Conserved sequence
More DNA
VNTRs
Primers that match Conserved sequence
Primer 2
Primer 1
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The Polymerase Chain Reaction (PCR)
Conserved sequence
Conserved sequence
VNTRs
1) Melt DNA heat it to 95 degrees C.
2) Cool to allow primers to bind DNA
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3) DNA polymerase binds double stranded DNA
4) DNA synthesis
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5) Melt DNA
6) Cool and allow primers to bind
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7) DNA synthesis
8) Melt DNA, allow primers to bind, DNA synthesis
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(No Transcript)
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You must know how much variation there is in the
population for the sequence you are using as a
fingerprint
Only a little false positives
Use many loci to reduce the possibility of false
positives
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D2s44 locus  - a highly variable locus   There
are 28 different alleles of the D2s44 locus   so
for two people to have the identical genotype if
all the alleles are equally common
1/28 1/28 .0013 or 13 in 1000  
if you test 10 genes, each with 28
alleles   .0013 .0013.. (.0013)10 a very
small chance of a false positive
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The human genome project established in 1990 as
a joint venture of over 12 countries

• Goals
• Map the 22 autosomes, X and Y
• Identify our genes (30,000 - 40,000)
• Sequence our genome (3 billion nucleotides)
• Sequence and map other model organisms
• Develop computing technologies to analyze data
• Disseminate information, consider ethical
• Implications ie. GATTACA, Health Insurance

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• Whose DNA?
• two males
• three females
• includes a Caucasian, African American,
• Hispanic, and Asian

Hoped to have 1/3 of the genome sequenced by 2001
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Method for cloning the Human genome
New, faster strategy shotgun cloning
developed by Craig Venter, skips restriction
mapping. the project was finished in 2001
EcoRI cut
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Shotgun Cloning
1) Isolate human chromosome
2) Isolate DNA from chromosome
3) Shear DNA into bits, clone bits into bacterial
plasmids
4) Sequence bits
5) Find and align overlapping sequence
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• 95 does not code for protein!
• 31 shared with yeast
• 40 with nematode roundworms
• 50 with fruit flies
• 90 with mice

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Human proteome project is next What is the
function of all these sequences?