think about… 29.1 recombinant dna technology 29.2 d na fingerprinting 29.3 human genome project

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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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reference DNA

from personal items

from family members

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Why can DNA be used in identifyinga person1

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Why can DNA be obtained frompersonal items2

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Why can DNA samples from familymembers serve as reference in victim identification

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Think about…29.1 Recombinant DNA technology29.2 DNA fingerprinting29.3 Human Genome ProjectRecall ‘Think about…’Summary concept map

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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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advances in biotechnology

(生物工程 )

recombinant DNA technology (重組 DNA 技

術 )

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• 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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Domestication of plants and animals throughout human civilization

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• 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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genetic engineering (遺傳工程 )

recombinant DNA technology (重組 DNA 技

術 )

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genetic engineering (遺傳工程 )• changing of the genetic

make-up of an organism by direct manipulation of genes or DNA


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How does recombinant DNA technology work?

There are three steps.

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Obtain DNA fragments containing the gene of interest

donor cell

DNA containing gene of interest

gene of interest

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Cut DNA fragments and plasmids with a specific enzyme

plasmid (質粒 )

• a small ring of extrachromosomal DNA in bacteria

• used as a vector (載體 )

bacterium

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Cut DNA fragments and plasmids with a specific enzyme

gene of interest plasmid (質粒 )

enzymes

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Join the gene of interest and plasmid together using an enzyme

gene of interest plasmid (質粒 )

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recombinant DNA (重組 DNA) / recombinant

plasmid (重組質粒 )

Animation

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introduce it into a host cell (宿主細胞 ) for replication and expression

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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

4

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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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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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1 Medicine• to produce pharmaceutical products

insulin production site

GM bacteria recombinant human insulin

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• gene therapy (基因治療 )

vectors with a normal gene

cell with a defective gene

1 Medicine

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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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GM soybean plants resistant to herbicides


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GM tomatoes that have longer shelf life


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GM rice that has more vitamin


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3 Chemical industries• to produce GM microorganisms that can

produce the following more efficiently:

enzymes

amino acids

polysaccharides

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4 Environmental protection• to produce GM bacteria that can break

down oil spills more efficiently

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5 Ore mining• to produce GM bacteria that can extract

metals more efficiently from ores• Eg.bacteria catalyse the breakdown of the mineral pyrite (FeS2) by oxidising

the sulfur and metal (in this case ferrous iron, (Fe2+) using oxygen.

• This yields soluble products that can be further purified and refined to yield the desired metal.

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1 is the DNA that results from the combination of DNA fragments from two different cells or organisms.

Recombinant DNA


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2 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.

Recombinant DNA technology


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a Obtain DNA fragments containing the from donor cells through proper processes.

3 Major steps in recombinant DNA technology:

gene of interest


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b Cut the DNA containing the gene of interest with a specific

. Cut open a plasmid using the same .enzyme



enzyme

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c Join the and the together with the help of another enzyme.

D _____ the organisms that acquire the gene of interest

gene of interestplasmid



select

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a To produce products and for

in medicine.

4 Applications of recombinant DNA technology:

gene therapy


pharmaceutical

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b To improve the and of farm animals and

crops in agriculture.

productivityquality



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c To produce in food production. food

genetically modified



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d To produce that can

produce enzymes, amino acids or polysaccharides more efficiently.

organismsgenetically modified



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e To produce genetically modified organisms that can break down

more efficiently.oil spills



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f To produce genetically modified organisms that can extract more efficiently from ores.

metals



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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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Obtain DNA fragments containing the highly variable regions

size varies among individuals

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Separate DNA fragments according to their size

gel electrophoresis (凝膠電泳 )

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Produce DNA fingerprints

DNA bands• pattern is unique to

each individual (except identical twins)

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• uses an electric field to drive DNA fragments to the positive terminal


Gel electrophoresis

negatively charged!

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• molecular space in the gel allows shorter DNA fragments to move faster than the longer ones


Gel electrophoresis

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Gel electrophoresis

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Gel electrophoresis

longer fragments

shorter fragments

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• DNA fragments separated into bands according to their size


Gel electrophoresis

longer fragments

shorter fragments

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• staining is required before the DNA bands can been seen


Gel electrophoresis

fluorescent under UV light

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Mix 80 cm3 of 5X TBE buffer solution and 320 cm3 of distilled water in a beaker.

29.1Separation of DNA fragments using gel electrophoresisA Preparation of 1X TBE buffer solution

Video


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29.1

1 Mix 60 cm3 of 1X TBE buffer solution and 0.9 g of agarose powder in a conical flask.

B Preparation of agarose gel

2 Heat the mixture over a hotplate until the agarose powder completely dissolves.


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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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29.1

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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29.1

1 Label the six tubes of DNA samples A to F.

C Gel electrophoresis of DNA fragments

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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29.1

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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29.1

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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29.1

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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29.1

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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1 Forensic science (法證科學 )


Applications of DNA fingerprinting

• to provide evidence to the court

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2 Victim identification



• to identify victims in disasters

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3 Parentage test (親子鑑證 )



• to establish family relationships

Animation

father mother child

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1 refers to the techniques involved in the use of DNA analyses to identify individuals.

DNA fingerprinting


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2 Steps in DNA fingerprinting:

a Extract from samples.

b Obtain containing highly variable

regions through proper processes.

DNA

DNA fragments


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c Separate DNA fragments using .

d Produce .

gel electrophoresisDNA fingerprints


2 Steps in DNA fingerprinting:

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3 Gel electrophoresis makes use of an electric field to drive DNA fragments to the terminal. DNA fragments move at speeds that depend on their .

positive size


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4 Applications of DNA fingerprinting:

a To provide evidence to the court in .

b To in disasters. c To establish family

relationships in .

forensic scienceidentify victims

parentage tests


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• genome (基因組 ):- DNA sequence on one set of

chromosomes in an organism

29.3 Human Genome Project

•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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• research project started in 1990What is the HGP about?• involved scientists from >18 countries


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• goals:- DNA sequencing of human DNA- mapping of human gene loci- develop new technologies e.g

diagnostic or therapeutic techniques

- address the ethical (道德倫理的 ), legal and social issues


What is the HGP about?

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HGP started

1990

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sequencing of yeast genome and mouse genome completed

1996

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sequencing of first human chromosome completed

1999

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draft version of human genome sequence completed

2000

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finished version of human genome sequence completed

2003

• all goals achieved, two years earlier than expected!

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2003

• all goals achieved, two years earlier than expected!

analyses of data continue

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The human genome project

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1 Better understanding of geneticsBenefits of the HGP

2 Improved diagnoses and treatment of diseases


breast cancer

gene related to

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3 Better understanding of evolutionBenefits of the HGP


similarity in base sequence

98% 85%

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3 Better understanding of evolutionBenefits of the HGP


more closely related

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1 The genetic data obtained may still not be enough to understand all biological processes.

Limitations of the HGP

2 It has raised ethical, legal and social issues.

The Ethical, Legal, and Social Implications (ELSI) program as an integral part of the Human Genome Project.


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Example:Limitations of the HGP


Who is the owner of personal genetic information?

I worked it out.

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I developed the technology.

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It’s my personal information.

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Who can gain access to personal genetic information?

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Would the diagnosis of an incurable disease cause anxiety?

I’m sorry. You have the faulty gene and there is no cure for the disease.

Oh no.

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Was that a rational decision?•After discovering a mutated BRCA1 gene, known to increase the likelihood of breast cancer 60 to 80 percent, actress Angelina Jolie underwent a radical preventive double mastectomy.

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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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a and of the human genome.

b Developing related new .

Sequencing

technologies

mapping


1 Goals of the Human Genome Project (HGP):

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1 Goals of the Human Genome Project (HGP):

c Addressing the , and issues.

ethicalsocial

legal

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2 The contributions of the data obtained from the HGP:

a Better understanding of

. b Improved and of diseases.

genetics

treatmentdiagnoses

c Better understanding of . evolution

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still not be enough to understand all .


3 The limitations of the data obtained from the HGP:

a The genetic data obtained may

biological processesb They have raised ethical,

legal and social issues.

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Why can DNA be used in identifyinga person?1

Like fingerprints, the DNA sequence is unique to each individual (except identical twins).

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Why can DNA be obtained frompersonal items?2Samples such as blood and hair with hair roots may be left on such personal items.

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Why can DNA samples from familymembers serve as reference in victim identification?

3The closer the family relationship, the more similar are the DNA sequences.

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is aboutApplied genetics

applications of genetics knowledge

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applied in

recombinant DNA technology

examples include


production of GMOs

pharmaceutical products

GM food

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applied inDNA fingerprinting


forensic science

victim identification

parentage test

examples include

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raisesHuman Genome Project


ethical, legal and social issues

examples include

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better understanding

of genetics

better understanding

of evolution

improved diagnoses and treatment of diseases

data contributes to Human Genome Project

think about… 29.1 recombinant dna technology 29.2 d na fingerprinting 29.3 human genome project

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