Bio111-ch13-2007.ppt - Campbell

whooshdisguisingBiotechnology

Dec 14, 2012 (4 years and 8 months ago)

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Chapter 13
-

Biotechnology

What is biotechnology?

What is biotechnology used for?

What are the tools of biotechnology?


What is biotechnology? (p. 252)


Alteration of organisms, cells, or
biological molecules to achieve specific
practical goals

What is biotechnology used for?

Production of pharmaceuticals

Production of commercial
compounds

To better understand the functions
and interactions of genes


-
Advances in medical diagnoses &
treatments


-
Advances in agriculture

Environmental cleanup

Forensics



What are the tools of biotechnology?

Breeding and artificial selection

Recombinant DNA technologies

DNA probe technologies

DNA transfer technologies


Breeding and artificial selection (p. 252)

Genetic manipulation in the
Brassica

family

(Europe & Mediterranean)


Teosinte


ancestor of corn (Mexico)

Cob selection

5000BC


2cm

3000BC


4cm

1000AD


13cm

Breeding and artificial selection

Recombinant DNA technologies (p. 252)


Combining genes or parts of genes from
different organisms



Transgenic


organisms containing
“foreign” genes

Genetically modified organisms = GMOs

Recombinant products

rBST and dairy products

rDNA origin

DNA recombination occurs naturally


1. Sexual reproduction (crossing over)


2. Bacterial transformation (p. 252)


3. Viral transfer of DNA (p. 253)

Recombinant DNA technologies

1.
Isolating DNA from cells

2.
Restriction enzymes

3.
Gel electrophoresis

4.
Polymerase chain reaction

5.
DNA probes & hybridization

Isolating DNA from cells

Cell membranes are lysed in detergent

Proteins are removed by precipitation

DNA is precipitated with alcohol

Restriction enzymes cut DNA molecules
(p. 262)

Restriction endonucleases
(enzymes) cut DNA at
specific short palindromic nucleotide sequences

Gel electrophoresis separates DNA
fragments by size (p. 257)

Gel electrophoresis animation

Polymerase chain reaction (PCR) copies
specific DNA sequences (p. 255)

A thermal cycler

PCR=repetitive DNA replication

Figure 13
-
3b
Biology: Life on Earth

8/e ©2008 Pearson Prentice Hall, Inc.

Each PCR cycle doubles the number of copies of the DNA.

DNA

copies

PCR

cycles

1

2

4

8

16 etc.

1

2

3

4 etc.

DNA

fragment

to be

amplified

Polymerase chain reaction (PCR)

25
-
30 PCR cycles
yield ~1 million
copies of the DNA
sample

Can be used on trace
quantities of DNA

Saliva, hair follicle,
trace dried blood



Forensic DNA analysis (p. 258)


Based on PCR of STRs (Short tandem
repeats, p. 255
-
256)


PCR, STRs and DNA profiles (p. 258)


The greater the number
of repeats, the longer
the DNA pieces
amplified by PCR

STR profiles and identity (p. 258)



Number of repeats varies (i.e. There are numerous STR “alleles”)

Restriction enzymes & biotechnology

(p. 260)

Restriction enzymes cut DNA molecules at
specific nucleotides, creating small
fragments


Applications:


Cloning genes


Medical diagnosis

Figure 13
-
9
Biology: Life on Earth

8/e ©2008 Pearson Prentice Hall, Inc.

single
-
stranded

“sticky ends”

A specific restriction enzyme (
Eco
RI) binds

to the GAATTC sequence and cuts the DNA,

creating DNA fragments with “sticky ends.”

Restriction enzymes cut DNA molecules at
palindromic nucleotide sequences (p. 260)

Genes can be
cloned using
restriction
enzymes and
bacterial
transformation
(p. 259)

Restriction enzymes and disease diagnosis


RFLP (
R
estriction
F
ragment
L
ength
P
olymorphism)
analysis
(p. 262)



http://highered.mcgraw
-
hill.com/olc/dl/120078/bio20.swf

RFLP analysis can be used in genetic
disease diagnosis (p. 262
-
263)



DNA transfer technologies are used in
genetic engineering (p. 252)


Genetic engineering

-

Addition, deletion,
or modification of genes in an organism



Genetic engineering is not limited to the
genome of the organism being
manipulated

Gene transfer into plants:

Agrobacterium tumefaciens
(p. 260)

http://highered.mcgraw
-
hill.com/olc/dl/120078/bio40.swf

Figure 13
-
10
Biology: Life on Earth

8/e ©2008 Pearson Prentice Hall, Inc.

(e) Insert
Bt
gene into plant chromosome.

(a) Cut both with the same restriction enzyme.

(b) Mix
Bt
gene and plasmid; add DNA ligase

to seal DNA.

(c) Transform
Agrobacterium tumefaciens

with recombinant plasmid.

(d) Infect plant cell with transgenic bacterium.

DNA including

Bt
gene

Ti plasmid

A. tumefaciens

bacterial

chromosome

plasmids

A. tumefaciens

plant cell

plant

chromosomes

Bt
gene

DNA transfer (Genetic engineering) requires cloning

a desired gene into a plasmid DNA molecule (p. 260)

The BT gene from

Bacillus thuringiensis
produces an insecticidal protein (p. 259)

BT spores form insecticidal
crystal proteins

Plant biotechnology: Insect resistant crop
plants

Bacillus thuringiensis

produces an
insecticidal protein (BT)

Plant biotechnology: Herbicide resistant
plants

Figure E13
-
4
Biology: Life on Earth

8/e ©2008 Pearson Prentice Hall, Inc.

Engineered rice for enhanced vitamin content (p. 267)

Genetic engineering in plants: Gene gun

Genetic engineering of animals

GFP bunny

Salmon growth hormone gene engineered
for constitutive (always on) expression

Table 13
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2
Biology: Life on Earth

8/e ©2008 Pearson Prentice Hall, Inc.

How is biotechnology used in human
medicine? (p. 264)

DNA microarrays allow simultaneous
analysis of many genes (p. 264)


DNA microarray analysis is based on
complementary base pairing


A DNA probe will
hybridize with a
complementary
DNA sequence of
a specific gene

C

T

A

A

G

A

G

C

G

A

T

T

C

T

C

G

C

:


G

T

:


A

A

:


T

A

:


T

G

:


C

A

:


T

G

:


C

C

:


G

DNA microarrays contain DNA probes to
thousands of genes

DNA probes

Microarray structure

(
http://www.affymetrix.com/corporate/outreach/lesson_plan/educator_resources.affx
)

DNA microarrays can be used to diagnose
genetic disease (p. 263)

DNA microarrays are used to associate
genes & phenotypes

Gene expression
microarray assay

Genes expressed in specific cell types or under certain
circumstances can be identified with microarrays

(http://www.affymetrix.com/corporate/outreach/lesson_plan/educator_resources.affx)

Associating gene expression with phenotype

(http://www.four
-
h.purdue.edu/apple_genomics/flash/movie7.swf)

Example: Identifying leukemia class to
determine best drug treatment


ALL

AML

Which class of leukemia
(class is distinguished by
which genes are
expressed/not expressed)?

Golub, T.R., et al.
Science

286: 531
-
537, 1999; Armstrong, S.A., et al.
Nature
Genetics

30: 41
-

47, 2002


MLL

Need more help understanding microarrays?

Visit:


http://learn.genetics.utah.edu/units/biotech/
microarray/microarray.swf


For an in depth interactive tutorial!

Gene therapy as a disease treatment

Somatic cell gene therapy utilizes genetically

engineered stem cells to treat genetic disease (p. 265)


Germline gene therapy (p. 270)