ppt_ch29_applied genetics_oxf

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Transcript ppt_ch29_applied genetics_oxf

1
Think about…
29.1 Recombinant DNA technology
29.2 DNA fingerprinting
29.3 Human Genome Project
Recall ‘Think about…’
Summary concept map
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Victims of disasters can be identified by
their fingerprints, dental information or
birthmarks.
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These methods may not work when the
remains are incomplete.
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Identification may be done by matching
the DNA.
DNA of the
remains
reference
DNA
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Identification may be done by matching
the DNA.
DNA of the
remains
reference
DNA
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from personal items
from family members
reference
DNA
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Why can DNA be used in identifying
a person
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2
Why can DNA be obtained from
personal items
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3
Why can DNA samples from family
members serve as reference in victim
identification
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29.1 Recombinant DNA
technology
Applied genetics is about how
the knowledge of genetics can
be used for the good of society.
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29.1 Recombinant DNA
technology
advances in
biotechnology
(生物工程)
recombinant
DNA technology
(重組 DNA 技術)
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29.1 Recombinant DNA
technology
• techniques that a fragment of DNA from
a donor cell or organism is isolated and
inserted into the DNA of another cell or
organism
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29.1 Recombinant DNA
technology
• can modify the characteristics of an
organism more quickly and precisely
• allows transfer of new characteristics
to organisms of different species
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29.1 Recombinant DNA
technology
recombinant
DNA technology
(重組 DNA 技術)
genetic
engineering
(遺傳工程)
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29.1 Recombinant DNA technology
genetic
engineering
• changing of the genetic (遺傳工程)
make-up of an organism
by direct manipulation
of genes or DNA
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29.1 Recombinant DNA technology
How does recombinant DNA
technology work?
There are three steps.
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29.1 Recombinant DNA technology
Obtain DNA fragments containing
the gene of interest
donor cell
DNA containing
gene of interest
gene of interest
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29.1 Recombinant DNA technology
Cut DNA fragments and plasmids
with a specific enzyme
• a small ring of
extrachromosomal
DNA in bacteria
• used as a vector
(載體)
bacterium
plasmid
(質粒)
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29.1 Recombinant DNA technology
Cut DNA fragments and plasmids
with a specific enzyme
enzymes
gene of interest
plasmid
(質粒)
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29.1 Recombinant DNA technology
Join the gene of interest and
plasmid together using an enzyme
gene of interest
plasmid
(質粒)
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29.1 Recombinant DNA technology
Join the gene of interest and
plasmid together using an enzyme
recombinant DNA
(重組 DNA) /
recombinant
plasmid (重組質粒)
Animation
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29.1 Recombinant DNA technology
Join the gene of interest and
plasmid together using an enzyme
introduce it into a host cell (宿主細胞)
for replication and expression
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29.1 Recombinant DNA technology
4 Select the organisms that have
acquired the gene of interest
Antibiotic resistance tests: The bacteria in the culture on the left are
susceptible to the antibiotics contained in the white paper discs. The
bacteria in the culture on the right are resistant to most of the antibiotics
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29.1 Recombinant DNA technology
What are the applications of
recombinant DNA technology?
Genetically modified organism (GMO)
(基因改造生物)
• an organism whose genetic make-up
has been changed in a way that does
not occur naturally by mating
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29.1 Recombinant DNA technology
What are the applications of
recombinant DNA technology?
Genetically modified food (GM food)
(基因改造食物)
• food made from GMOs or their
components
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29.1 Recombinant DNA technology
1 Medicine
• to produce pharmaceutical products
insulin production site
GM bacteria
recombinant
human insulin
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29.1 Recombinant DNA technology
1 Medicine
• gene therapy (基因治療)
vectors with a
normal gene
cell with a
defective
gene
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29.1 Recombinant DNA technology
2 Agriculture and food
production
• to improve productivity and quality of
farm animals and crops
non-GM
salmon
GM salmon that grow faster
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29.1 Recombinant DNA technology
2 Agriculture and food
production
• to improve productivity and quality of
farm animals and crops
GM soybean
plants resistant
to herbicides
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29.1 Recombinant DNA technology
2 Agriculture and food
production
• to improve productivity and quality of
farm animals and crops
GM tomatoes
that have
longer shelf life
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29.1 Recombinant DNA technology
2 Agriculture and food
production
• to improve productivity and quality of
farm animals and crops
GM rice that
has more
vitamin
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29.1 Recombinant DNA technology
3 Chemical industries
• to produce GM microorganisms that can
produce the following more efficiently:
enzymes
amino acids
polysaccharides
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29.1 Recombinant DNA technology
4 Environmental protection
• to produce GM bacteria that can break
down oil spills more efficiently
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29.1 Recombinant DNA technology
5 Ore mining
• to produce GM bacteria that can extract
metals more efficiently from ores
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29.1 Recombinant DNA technology
1 Recombinant DNA
is the DNA
that results from the combination
of DNA fragments from two
different cells or organisms.
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29.1 Recombinant DNA technology
2
Recombinant DNA technology
refers to the techniques that a
fragment of DNA from a donor cell
or organism is isolated and inserted
into the DNA of another cell or
organism.
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29.1 Recombinant DNA technology
3 Major steps in recombinant DNA
technology:
a Obtain DNA fragments containing
the gene of interest from donor
cells through proper processes.
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29.1 Recombinant DNA technology
4 Major steps in recombinant DNA
technology:
b Cut the DNA containing the
gene of interest with a specific
enzyme . Cut open a plasmid
using the same enzyme .
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29.1 Recombinant DNA technology
4 Major steps in recombinant DNA
technology:
c Join the gene of interest and
the plasmid together with the
help of another enzyme.
D select
_____ the organisms that
acquire the gene of interest
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29.1 Recombinant DNA technology
4 Applications of recombinant DNA
technology:
a To produce
pharmaceutical
products and for gene therapy
in medicine.
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29.1 Recombinant DNA technology
4 Applications of recombinant DNA
technology:
b To improve the
productivity and
quality of farm animals and
crops in agriculture.
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29.1 Recombinant DNA technology
4 Applications of recombinant DNA
technology:
c To produce
genetically modified
food in food production.
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29.1 Recombinant DNA technology
4 Applications of recombinant DNA
technology:
d To produce
genetically modified
organisms that can produce
enzymes, amino acids or
polysaccharides more efficiently.
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29.1 Recombinant DNA technology
4 Applications of recombinant DNA
technology:
e To produce genetically modified
organisms that can break down
oil spills more efficiently.
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29.1 Recombinant DNA technology
4 Applications of recombinant DNA
technology:
f To produce genetically modified
organisms that can extract metals
more efficiently from ores.
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29.2 DNA fingerprinting
• techniques involved in the use of
DNA analyses to identify individuals
How do scientists produce
DNA fingerprints?
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29.2 DNA fingerprinting
Extract DNA
DNA
cells in blood
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29.2 DNA fingerprinting
Obtain DNA fragments containing
the highly variable regions
size varies
among individuals
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29.2 DNA fingerprinting
Separate DNA fragments
according to their size
gel electrophoresis
(凝膠電泳)
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29.2 DNA fingerprinting
Produce DNA fingerprints
DNA bands
• pattern is unique to
each individual
(except identical twins)
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29.2 DNA fingerprinting
Gel electrophoresis
• uses an electric field to drive DNA
fragments to the positive terminal
negatively
charged!
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29.2 DNA fingerprinting
Gel electrophoresis
• molecular space in the gel allows shorter
DNA fragments to move faster than the
longer ones
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29.2 DNA fingerprinting
Gel electrophoresis
• molecular space in the gel allows shorter
DNA fragments to move faster than the
longer ones
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29.2 DNA fingerprinting
Gel electrophoresis
• molecular space in the gel allows shorter
DNA fragments to move faster than the
longer ones
longer
fragments
shorter
fragments
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29.2 DNA fingerprinting
Gel electrophoresis
• DNA fragments separated into bands
according to their size
longer
fragments
shorter
fragments
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29.2 DNA fingerprinting
Gel electrophoresis
• staining is required before the DNA
bands can been seen
fluorescent
under UV light
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29.2 DNA fingerprinting
29.1
Video
Separation of DNA fragments using gel
electrophoresis
A Preparation of 1X TBE buffer solution
Mix 80 cm3 of 5X
TBE buffer solution
3
and 320 cm of
distilled water in a
beaker.
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29.2 DNA fingerprinting
29.1
B Preparation of agarose gel
3
1 Mix 60 cm of 1X TBE buffer solution and
0.9 g of agarose powder in a conical flask.
2 Heat the mixture
over a hotplate until
the agarose powder
completely dissolves.
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29.2 DNA fingerprinting
29.1
3 Cool down the agarose solution to about
60ºC.
4 Seal the two ends of
the gel mould with
sticky tape and pour
the agarose solution
into the gel mould
slowly.
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29.2 DNA fingerprinting
29.1
5 Insert the gel comb into the gel mould at
one side.
6 After about 30 minutes, remove the gel
comb and sticky tape carefully.
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29.2 DNA fingerprinting
29.1
C Gel electrophoresis of DNA fragments
1 Label the six tubes of DNA samples A to F.
2 Put the gel with the gel mould in the
electrophoresis tank. The side with the
wells should be placed at the cathode (-)
of the tank.
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29.2 DNA fingerprinting
29.1
3 Add 1X TBE buffer solution until the gel is
covered.
4 Starting from the leftmost well, slowly load
the DNA marker, DNA samples A to F into
separate wells using a syringe fitted with a
plastic tip. Wash the syringe with a new
buffer solution between successive loadings.
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29.2 DNA fingerprinting
29.1
5 Cover the lid of the electrophoresis tank.
Connect the electrodes and turn on the
power supply to apply a 100 V d.c. voltage
across the gel.
100 V
-
+
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29.2 DNA fingerprinting
29.1
6 After about 60 minutes, when the tracking
dyes reach about half to two thirds of the
length of the gel, turn off the power supply.
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29.2 DNA fingerprinting
29.1
7 Put the gel into a plastic lunch box
containing methylene blue solution.
Leave the gel for about 12 hours.
8 Take a photo of the
gel with DNA
bandings.
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29.2 DNA fingerprinting
Applications of DNA
fingerprinting
1 Forensic science (法證科學)
• to provide evidence to the court
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29.2 DNA fingerprinting
Applications of DNA fingerprinting
2 Victim identification
• to identify victims in disasters
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29.2 DNA fingerprinting
Applications of DNA
fingerprinting
3 Parentage test (親子鑑證)
• to establish
family
mother
father
relationships
Animation
child
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29.2 DNA fingerprinting
1
DNA fingerprinting refers to the
techniques involved in the use of
DNA analyses to identify individuals.
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29.2 DNA fingerprinting
2 Steps in DNA fingerprinting:
a Extract DNA from samples.
b Obtain DNA fragments
containing highly variable
regions through proper
processes.
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29.2 DNA fingerprinting
2 Steps in DNA fingerprinting:
c Separate DNA fragments
using gel electrophoresis .
d Produce DNA fingerprints .
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29.2 DNA fingerprinting
3 Gel electrophoresis makes use
of an electric field to drive DNA
fragments to the positive terminal.
DNA fragments move at speeds
that depend on their size .
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29.2 DNA fingerprinting
4 Applications of DNA fingerprinting:
a To provide evidence to the court
in forensic science .
b To identify victims in disasters.
c To establish family relationships
in parentage tests .
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29.3 Human Genome Project
• genome (基因組):
- DNA sequence on one set of
chromosomes in an organism
•A colorized electron micrograph of Haemophilus
influenzae, a bacterium that was the first free-living
organism to have its genome sequenced, in 1995.
•This bacterium causes respiratory infections and
bacterial meningitis (inflammation of the protective
membranes of the brain) in humans.
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29.3 Human Genome Project
What is the HGP about?
• research project started in 1990
• involved scientists from >18 countries
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29.3 Human Genome Project
What is the HGP about?
• goals:
- DNA sequencing of human DNA
- mapping (定位) of human DNA
- develop related new technologies
- address the ethical (道德倫理的),
legal and social issues
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29.3 Human Genome Project
What is the HGP about?
1990
HGP started
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29.3 Human Genome Project
What is the HGP about?
1996
sequencing of yeast genome and
mouse genome completed
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29.3 Human Genome Project
What is the HGP about?
1999
sequencing of first human
chromosome completed
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29.3 Human Genome Project
What is the HGP about?
2000
draft version of human
genome sequence completed
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29.3 Human Genome Project
What is the HGP about?
• all goals achieved, two years earlier than
expected!
2003
finished version of human
genome sequence completed
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29.3 Human Genome Project
What is the HGP about?
• all goals achieved, two years earlier than
expected!
2003
analyses of
data continue
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29.3 Human Genome Project
Benefits of the HGP
1 Better understanding of genetics
2 Improved diagnoses and treatment of
diseases
gene
related to
breast cancer
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29.3 Human Genome Project
Benefits of the HGP
3 Better understanding of evolution
98%
85%
similarity in base sequence
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29.3 Human Genome Project
Benefits of the HGP
3 Better understanding of evolution
more closely related
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29.3 Human Genome Project
Limitations of the HGP
1 The genetic data obtained may still not
be enough to understand all biological
processes.
2 It has raised ethical, legal and social
issues.
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29.3 Human Genome Project
Limitations of the HGP
Example: Who is the owner of personal
genetic information?
I worked it out.
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29.3 Human Genome Project
Limitations of the HGP
Example: Who is the owner of personal
genetic information?
I developed the technology.
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29.3 Human Genome Project
Limitations of the HGP
Example: Who is the owner of personal
genetic information?
It’s my personal information.
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29.3 Human Genome Project
Limitations of the HGP
Example: Who can gain access to personal
genetic information?
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29.3 Human Genome Project
Limitations of the HGP
Example: Would the diagnosis of an
incurable disease cause anxiety?
Oh no.
I’m sorry. You
have the faulty
gene and there
is no cure for
the disease.
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29.3 Human Genome Project
Limitations of the HGP
Example: How does the personal genetic
information affect the public perception of
an individual?
Go! He has a
gene related
to violence.
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29.3 Human Genome Project
1 Goals of the Human Genome
Project (HGP):
a
Sequencing and mapping of
the human genome.
b Developing related new
technologies .
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29.3 Human Genome Project
1 Goals of the Human Genome
Project (HGP):
c Addressing the ethical ,
legal
and social issues.
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29.3 Human Genome Project
2 The contributions of the data
obtained from the HGP:
a Better understanding of genetics .
b Improved diagnoses and
treatment of diseases.
c Better understanding of
evolution .
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29.3 Human Genome Project
3 The limitations of the data obtained
from the HGP:
a The genetic data obtained may
still not be enough to understand
all biological processes .
b They have raised ethical,
legal and social issues.
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1
Why can DNA be used in identifying
a person?
Like fingerprints, the DNA sequence is
unique to each individual (except
identical twins).
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2
Why can DNA be obtained from
personal items?
Samples such as blood and hair with
hair roots may be left on such personal
items.
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3
Why can DNA samples from family
members serve as reference in victim
identification?
The closer the family relationship, the
more similar are the DNA sequences.
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Applied genetics
is about
applications of
genetics knowledge
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applications of
genetics knowledge
examples include
recombinant
DNA technology
applied in
production of
for
GMOs
pharmaceutical
products
producing
GM food
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applications of
genetics knowledge
examples include
DNA fingerprinting
applied in
forensic
victim
parentage
science identification
test
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applications of
genetics knowledge
examples include
Human Genome Project
raises
ethical, legal and
social issues
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Human Genome Project
data contributes to
better
understanding
of genetics
better
understanding
of evolution
improved diagnoses and
treatment of diseases
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