2006-2007 Regents Biology

Aim: How can we analyze DNA?

Do Now:

1. What are the advantages of selective breeding? Give an example.

Hw:

2006-2007 Regents Biology

Aim: How can we model the technique of gel electrophoresis?

Pre-Lab Questions

1. What happens to DNA prior to electrophoresis?

2.How is DNA separated in gel electrophoresis?

3. How are the bands DNA arranged in the gel?

Hw: Read pgs. 173-174 Answer Regents Practice B 12 on pg. 184, Part C 20 on pg. 185. Read pgs. 80 & 81 Define theory, fossil record, geologic time.

2006-2007 Regents Biology

BiotechnologyGel Electrophoresis

Regents Biology

Many uses of restriction enzymes… Now that we can cut DNA with

restriction enzymes… we can cut up DNA from different

people… or different organisms… and compare it

why? forensics medical diagnostics paternity evolutionary relationships and more…

Regents Biology

Comparing cut up DNA How do we compare DNA fragments?

separate fragments by size

How do we separate DNA fragments? run it through a gelatin gel electrophoresis

How does a gel work?

Regents Biology

Gel electrophoresis A method of separating

DNA in a gelatin-like material using an electrical field DNA is negatively charged when it’s in an electrical

field it moves toward the positive side

+–

DNA

“swimming through Jello”

Regents Biology

DNA moves in an electrical field… so how does that help you compare DNA

fragments? size of DNA fragment affects how far it travels

small pieces travel farther

large pieces travel slower & lag behind

Gel electrophoresis

+–

DNA

“swimming through Jello”

Regents Biology

Gel Electrophoresis

longer fragments

shorter fragments

powersource

completed gel

gel

DNA &restriction enzyme

wells

-

+

Regents Biology

Running a gel

1 2

cut DNA with restriction enzymes

fragments of DNAseparate out based

on size

3

Stain DNA ethidium bromide

binds to DNA fluoresces under

UV light

Regents Biology

DNA fingerprint Why is each person’s DNA pattern different?

sections of “junk” DNA doesn’t code for proteins made up of repeated patterns

CAT, GCC, and others

each person may have different number of repeats

many sites on our 23 chromosomes with different repeat patterns

GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTTCGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGAA

GCTTGTAACGGCATCATCATCATCATCATCCGGCCTACGCTTCGAACATTGCCGTAGTAGTAGTAGTAGTAGGCCGGATGCGAA

Regents Biology

Allele 1GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTTCGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGAA

repeats

DNA patterns for DNA fingerprintscut sitescut sites

GCTTGTAACG GCCTCATCATCATCGCCG GCCTACGCTTCGAACATTGCCG GAGTAGTAGTAGCGGCCG GATGCGAA

1 2 3

DNA – +allele 1

Cut the DNA

Regents Biology

Person 1GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTTCGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGAA

Differences between peoplecut sitescut sites

DNA – +person 1

Person 2: more repeats

GCTTGTAACGGCCTCATCATCATCATCATCATCCGGCCTACGCTTCGAACATTGCCGGAGTAGTAGTAGTAGTAGTAGGCCGGATGCGAA

DNA fingerprint

person 2

1 2 3

Regents Biology

Uses: Evolutionary relationships Comparing DNA samples from different

organisms to measure evolutionary relationships

–

+

DNA

1 32 4 5 1 2 3 4 5

turtle snake rat squirrel fruitfly

Regents Biology

Uses: Medical diagnostic Comparing normal allele to disease allele

chromosome with disease-causing

allele 2

chromosomewith normal

allele 1 –

+

allele 1allele 2

DNA

Example: test for Huntington’s disease

Regents Biology

Uses: Forensics Comparing DNA sample from crime

scene with suspects & victim

–

+

S1

DNA

S2 S3 V

suspects crime scene sample

Regents Biology

DNA fingerprints Comparing blood

samples on defendant’s clothing to determine if it belongs to victim DNA fingerprinting

Regents Biology

RFLP / electrophoresis use in forensics 1st case successfully using DNA evidence

1987 rape case convicting Tommie Lee Andrews

“standard”

“standard”

“standard”

“standard”

semen sample from rapist

semen sample from rapist

blood sample from suspect

blood sample from suspect

How can you compare DNA from

blood & from semen?RBC?

Regents Biology

Electrophoresis use in forensics Evidence from murder trial

Do you think suspect is guilty?

“standard”

blood sample 3 from crime scene

“standard”

blood sample 1 from crime scene

blood sample 2 from crime scene

blood sample from victim 2

blood sample from victim 1

blood sample from suspect OJ Simpson

N Brown

R Goldman

Regents Biology

Uses: Paternity Who’s the father?

+

DNA

childMom F1 F2–

2006-2007 Regents Biology

I’m a-glow!

Got any Questions?

2006-2007 Regents Biology

Biodiversity Lab

Which plant is most closely related to Botanus curus?

Regents Biology

Botanus curus Sequences

CAC GTG GAC TGA GGA CTC CTCDNA

GUG CAC CUG ACU CCU GAG GAGRNA

Val His Leu Thr Pro Glu GluAA

Regents Biology

Species X Sequences

CAC GTG GAC AGA GGA CAC CTCDNA

GUG CAC CUG UCU CCU GUG GAGRNA

Val His Leu Ser Pro Val GluAA

CAC GTG GAC TGA GGA CTC CTCBC

Val His Leu Thr Pro Glu GluBC

Regents Biology

Species Y Sequences

CAC GTG GAC AGA GGA CAC CTCDNA

GUG CAC CUG UCU CCU GUG GAGRNA

Val His Leu Ser Pro Val GluAA

CAC GTG GAC TGA GGA CTC CTCBC

Val His Leu Thr Pro Glu GluBC

Regents Biology

Species Z Sequences

CAC GTA GAC TGA GGA CTT CTCDNA

GUG CAU CUG ACU CCU GAA GAGRNA

Val His Leu Thr Pro Glu GluAA

CAC GTG GAC TGA GGA CTC CTCBC

Val His Leu Thr Pro Glu GluBC

Regents Biology

Amino Acid Sequences

Val His Leu Thr Pro Glu Glu

BC

X

Y

Z

Val His Leu Thr Pro Glu Glu

Val His Leu Ser Pro Val Glu

Val His Leu Ser Pro Val Glu