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Flashcards in #2 Deck (37):
1

Every cell has a what

Identical copy of the DNA

Except erythrocytes

2

23 pairs of chromosomes=

46 total

3

How many pairs of autosomal chromosomes are there

22 pairs

4

How many pairs of sex chromosomes?

1 pair

5

XX

Female

6

XY

Male

7

What is locus

Lolci
Site on gene on a DNA strand

8

About how many genes in humans

35,000-45,000

9

DNA sampling

Slough off cells with DNA continuously
-blowing nose, brushing teeth, combing hair

10

During DNA sampling

CSI must wear masks & suits so as to not contaminate crime scene

11

DNA contamination can also occurs with mortuary tools so

Do DNA sampling before body is moved

12

Keep all samples

Separate

13

FTA Cards

Used to obtain a sample of DNA from liquid or tissue sources

14

FTA cards

Contain chemicals that lyse cells & immobilize & stabilize DNA & rna

Other chemicals preserve DNA & rna
Can be stored at room temp

15

FTA cards continued

Press against liquids, squash blood clots onto surface, drop liquids on cards

16

DNA profiling is

Sequencing an individuals dna

17

How to use DNA profiling

1) Use markers - specific genes w/ known loci used in test
2) DNA fingerprinting not the most accurate term
-all fingerprints are unique even for twins
- DNA is not 100% unique:identical twins have the same
3) DNA experts talk about probability of match, not definite match (1:10,000,000,000)

18

Exclusion def

DNA of a suspect not matching the evidence
Helps rule out suspect, release innocent persons

19

Inconclusive

DNA profile doesn't work
-contamination
- DNA degradation
- further analysis is needed to determine guilt or innocence

20

Inclusion def

A positive DNA match
State the random match probability -pm
Markers not linked - inherited independently

21

Profile limitations

DNA can degrade
Full profile can't be obtained
Close relatives share many Markers
From the same sub-population
Groups that intermarry share many markers too

22

Prosecuters fallacy

Assuming guilt based salely on statistical evidence.
DNA found at a crime scene therefore there is a 1:10,000,000,000 that this person could be innocent

23

Defense attorney fallacy

Assuming innocent based solely on statistical evidence
If pm is 1 in 1 million, & MN pop. Is 5 million the 4 other people could be the perpetrator

24

Profiling Applications steps

1) identify victims & assdilants of homicide & rape
2) minor crimes: Bulgary, car theft, hate mail, etc.
3) paternity tests
4) family relationships for visas/asylum
5) insurance comp. use for car accidents
-prove who was where during the accident

25

Polymerase Chain Reactions (PTC)

-Developed by Kary Mullis in 1983
-isolates & amplifies(copies) specific sequences of DNA
- does not affect surrounding reactions
- need flanking sequences of DNA
-build a DNA Primer to onneal(attach) to DNA sample
- Primer provides the 3-OH for DNA polymerase to bind to

26

DNA Primer

2 primers used
1 for each template strand

27

DNA polymerase

Use Taq DNA polymerase

28

Thermus acquaticus def

Bacterium found in hot springs at yellow stone national park

29

Taq DNA polymerase is

Able to withstand high temps w/ out dying
-allows PCR to happen w/out interruption

30

D1S80- Locus

Position on chromosome where a gene or a non-coding region can be found

31

MonomOrphic

All humans have essentially identical DNA sequence at that locus

32

Polymorphic

DNA sequence at locus varies among individuals

33

Variations at a locus are called

Alleles

34

D1S80 is found on

Chromosome 1

35

Chromosome 1 is a

Non coding region
No proteins are made

High degree of polymorphism

36

On chromosome 1 for D1S80

1) 29 different alleles at this locus
2) known as a variable number of Tandem respects(VNTRS)
3) repeating set of base pairs
In this case 16 nucleotides
4) the number repeats varies between individuals. This is what we are determining in the lab. 435 combinations
From 14-41 repeats.

37

Steps to D1S80

1) isolate DNA
Use sterile swap to collect cheek DNA
Mix w/ quick extract DNA solution to isolate & separate the DNA
2) PCR
Need: -DNA polymerase( Taq polymerase)
- 4 nucleotides(dATP, dGTP, dCTP,dTTP)
- DNA template(your check DNA)
- suitable conditions
- DNA Primer

3) analysis of D1S80 using gel electrophoresis
-transfer DNA from PCR tube to gel
- run gel
- analyze results