S5 Biology

E4 Biotechnology
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E4 Biotechnology
 What is Biotechnology?
Biotechnology is any technological application that involves the
use of organisms
___________________________________, biological systems or processes to
goods
produce ________________ services
or provide _________________.

Traditional Biotechnology
1. Fermentation
______________________:

Make use anaerobic respiration of microorganism to produce bread, wine, cheese, etc
____________________________________________________________________

2. Selective breeding
______________________ :

Produce crops and animals with desirable characters by selecting the best varieties to breed
____________________________________________________________________

Modern Biotechnology
Polymerase Chain Reaction
1. ____________________________ (PCR)

DNA Fingerprinting
2. _____________________________

Cloning
3. Plant & Animal __________________

Recombinant
4. __________________________________ technology
• Production of Pharmaceutical products e.g. human insulin, growth hormones, vaccine
• Production of Transgenic (GM) organisms
• Gene Therapy
5. Stem Cell Therapy
________________________________

6. Human Genome Therepy

_____________________________ (HGP)

 What is modern biotechnology?

Modern biotechnology refers to a range of processes and techniques that

involve the manipulation of DNA

______________________________________, cells
___________, tissues or

biological processes to attain knowledge, produce goods or provide services.

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P1
 S5 Biology
E4 Biotechnology
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Polymerase Chain Reaction (PCR)

 Each PCR cycle consists of 3 steps:

Double strandeed DNA is heated to 95 to break the H-bond and seperates to form single-stranded DNA
DNA denaturation
1. ___________________________ (separation of 2 strands of DNA to form single strands)
Cool to about 50 to 65 so that primers with complementary bases can anneal to single stranded DNA
Annealing of primers
2. ____________________________
Heat to 70 which provide optimum temperature for heat-stable DNA polymerase where complementary
DNA extention
3. ____________________________
free deoxyribonucleotides join to the primer to extend the NDA molecile catalyzed bu DNA polymerase

 How many copies of DNA are produced after 30 cycles of PCR reaction?
2 = 1 073 741 824
30
_________________________________________

 What reagents should be added

to run the PCR?
- DNA template
__________________________________

- Heat-stable DNA polymerase

__________________________________

- 2 different types of primers

__________________________________

- 4 types of deoxyribonucleotides (A,G,T,C)

__________________________________

- Buffer solution
__________________________________

 State 2 applications of PCR.

• To __________________
amplify bacteria for the
diagnosis of genetic/infectious
diseases.
• To amplify DNA from blood
samples found in a crime scene to
produce _______________________
fingerprinting

in forensic science.

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P2
 S5 Biology
E4 Biotechnology
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DNA fingerprinting
⚫ Most (95%) of human DNA does not code for any proteins.
⚫ Some of the non-coding DNA are highly variable regions which consist of many
different repeated base sequence called variable number tandem repeats (VNTRs)
(可變數目銜接重覆).
⚫ The number of repeats of each base sequence varies greatly from person to
person.
⚫ The variable number tandem repeats (VNTRs) of a person are stable within the
lifetime & inheritable to offspring.

For example:
A repeating sequence on chromosome 1: GAG GAC CAC CGG CAA G
⚫ If the number of repeats of this base sequence in father & mother are (12, 18) and (15, 30)
respectively, their children should have one of the following combinations:
12
(_______, 15 12
_______),(_______, 30
______), 15
(______, 18
______) 18
or (________, 30
________).
⚫ unrelated
However, there is a chance that an unrelated individual also has the __________
number of repeats.
⚫ several
In order to identify a person correctly, ______________ different variable number
tandem repeats (VNTRs) at different loci of the chromosomes should be examined.

 Based on the variable number tandem repeats (VNTRs) at 3 different loci, who is not
the biological child of the parents? Daughter
_________________

Loci X Y Z

Father 10, 14 18, 24 8, 9

Mother 12, 20 22, 22 8, 15

Son 10, 20 22, 24 8, 8

Daughter 12, 14 22, 22 26, 9

***To exclude identity is easy, to prove it is difficult. ***

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P3
 S5 Biology
E4 Biotechnology
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Restriction Fragment Length Polymorphism analysis

 DNA is extracted from cells (e.g. white blood cells in blood, cells from hair root or skin).
_____
 restriction enzyme
The extracted DNA is cut into small fragments by specific ________________________.
 The DNA fragments are put in a well at one end of a sheet of agarose gel.
 lengths
The DNA fragments are then separated according to their ________ using
gel electrophoresis
____________________________.
 single
The DNA in the gel is denatured i.e. made ___________-stranded by heating or
chemical treatment.
 nylon
The DNA fragments are transferred from the gel to a ________ membrane.
 radioactive
The nylon membrane is incubated with ______________ DNA probes which contain
complementary
_____________________ base sequences to part of the repeating sequences (VNTRs).
 bind
The radioactive DNA probes ____________ to the specific DNA fragments(VNTRs) on
the nylon membrane.
 washed
Unbound excess DNA probes are ____________ off the nylon membrane.
 photographic
A sheet of __________________ film is placed next to the membrane in a lightproof box.
 Radiation from the DNA probes irradiates the film. When the film is developed, the
dark bands
exposed areas appear as ____________________ making up the DNA fingerprint.
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 S5 Biology
E4 Biotechnology
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 What is radioactive DNA probe?

A DNA probe is a single
_________-strand DNA with a base sequence
complementary
_________________to part of the DNA fragment being studied. The DNA probe is
usually labelled with radioactive substance.

Polymerase Chain Reaction – Short Tandem Repeat Analysis

DNA
1. __________ is extracted from cells.

2. Specific DNA regions (highly variable short tandem repeat regions) are selectively

amplified
______________ polymerase chain reaction
by _______________________________________ (PCR).

gel electrophesis
3. DNA fragments are separated according to their lengths using __________________.

Stain
4. ___________ the gel in methylene blue solution to visualize the DNA. / Stain the gel in

ethidium bromide solution & visualize the DNA under UV light.

DNA bands
5. The patterns of _________________ in the gel become the DNA fingerprints.

Advantages:
⚫ smaller
Relatively ______________ amount of even partially degraded DNA can be used
⚫ quicker
simpler and _________________ method

Validity & Reliability of DNA fingerprinting

If the chance of 2 people sharing a band is ¼.

1. What is the chance for 2 people sharing 5 bands?

2. What is the world population?

3. How many people in the world share the same 5 bands?

4. What is the chance for 2 people sharing 18 bands?

5. How many people share the same 18 bands?

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P5
 S5 Biology
E4 Biotechnology
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Recombinant DNA technology

Use of insulin produced from recombinant D use of insulin extracted from animals.

(1) produced in larger quantity in a shorter time

(2) cheaper to produce
(3) more effective in controlling blood glucose level in diabetics
(4) fewer impurities => less likely to cause allergic reactions
(fewer side effects)

Insulin from animals for treating diabetes

⚫ Previously, the insulin was extracted from pancreas of pigs/cows.
⚫ The amino acid sequence & thus the 3D structure of the animal insulin is
slightly different
_________________________ from that of human insulin.
⚫ The B cells of the patients who receive the animal insulin recognize it as ___________ foreign
antigen
________ antibodies
& then ________________ rejection
are produced to act against it (i.e. _____________
on the animal insulin occurs).
⚫ Therefore, the animal insulin is __________ destroyed & its effect of treating diabetes is lowered.
⚫ limited
Also, only a ___________amount of insulin can be extracted from an animal pancreas &
purification
the ________________ complicated
process is _________________. Therefore, it is expensive.
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Describe the process of using recombinant DNA technology to produce human insulin for diabetics.
1. Identify the gene for production of insulin in human cells.

2. Obtain DNA containing the human insulin gene.

3. Cut the DNA segment containing the human insulin gene with a restriction enzyme.

4. Extract plasmids containing a certain antibiotic resistant gene from bacterial cells.

5. Cut open the plasmids with the same restriction enzyme.

6. Join the human insulin gene & the open plasmid together by DNA ligase to form a

recombinant plasmid.

7. Put the recombinant plasmids into a culture medium of bacteria.

8. Some of the bacteria will take up the recombinant plasmids.

9. Select the transformed bacteria by growing the bacteria on an agar plate containing

certain antibiotic.

10. Mass culture the selected recombinant bacteria to allow the expression of the human

insulin gene (i.e. production of human insulin).

11. Break open the bacterial cells, isolate & purify the human insulin produced.

☺ Use of insulin produced from recombinant DNA technology has

several advantages over the use of insulin extracted from animals.
larger quantity
(1) produced in __________________ in a shorter time as

the reproduction rate of bacteria is high

____________________________________________________

Cheaper
(2) _______________ high yield product and simple
to produce due to ______________________

purification process needed

____________________________________________________

allegeric
(3) fewer impurities => less likely to cause ___________ reactions

(fewer side effects) & no contamination of pathogens

(4) more effective in controlling blood glucose level in diabetics as

it has the same amino acid sequence as human insulin and thus is structurally identical to human insulin
____________________________________________________________________

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 S5 Biology
E4 Biotechnology
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A new Method developed by The HK Poly U for treating liver cancer

 Liver cancer --- the second most common cancer in China.

 260, 000 cases per year in China.
 No effective treatment --- most liver cancers are resistant to chemotherapy.
 Survival for patients is less than 6 months.
 New effective drugs with fewer side effects are therefore urgently needed.
 The HK Polytechnic University developed a new anti-liver-cancer drug treatment & won
international Gold Medal Awards in 2005.

Background Information of the novel method for treating liver cancer

 Human liver cells can synthesize arginase.

arginase
 arginine ornithine + urea
 Normal liver cells can synthesize arginine upon depletion.
 Liver cancer cells cannot produce arginine & thus they only obtain it
from the blood plasma.
 When liver cells are deprived of arginine, they will die.

Design an anti-liver-cancer drug treatment based on the information given.

arginase
 Synthesize _______________ recombinant DNA
using ___________________________ technology.

Inject arginase
 _____________ blood
into patient’s _______________.

arginine
 All _____________ otnithine
in the patient’s blood plasma is converted to _______________ &

urea
_______ arginase
by injected __________________.

deprived
 Liver cancer cells are _____________ die
of arginine and then _______.

synthesize
 Normal liver cells can _______________ their own arginine and thus are

not affected
________________________.

liver cancer
 Therefore, only the _____________________ cells are killed.

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Experimental Results on rats

Title: The change in the liver tumor size with time under different drug treatments

Control
Liver Tumor size(mm)

Traditional drug
(chemotherapy)

Recombinant
Arginase

Traditional drug
+ Recombinant
Arginase

Time (days)
What conclusion can you draw from the results?
little inhibitory effect
⚫ The traditional chemotherapy drug has ___________________________________ on the
liver tumor growth.
better
⚫ The recombinant arginase has __________ inhibitory effect on liver tumor growth
than the traditional drug when they are administrated alone.
largely increased
⚫ The inhibitory effect on liver tumor growth is ____________________________ if the
recombinant arginase is administrated together with the traditional drug.

Results of clinical trials on patients with terminal liver cancer at Queen Mary Hospital
 After blood test, the changes in the level of the following substances were found. State
the changes.
1. Ornithine Increased
________________

2. Arginine Dropped
________________

Dropped and remains at a low level

3. -foetal protein (liver cancer marker) _____________________________
side effects
 There are no ___________________ after the 6th weekly injection, indicating the drug is
safe
____________ for use in human.

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Gene Therapy
What is gene therapy?
adding normal genes into target cells in the human body
• To treat a genetic disease by ____________________________________________.
- By using vector (eg. harmless viruses, liposomes, microinjection) for transferring a normal gene into a target cell

Gene therapy can be done in 2 ways:

ex vivo
1. In _______________ gene therapy: cells are genetically modified outside the body

and then put back into the patient.

in vivo
2. In _______________ gene therapy: cells are genetically modified inside the body by

direct transfer of the normal genes into them.

Gene therapy can be divided into 2 types, depending on the type of cells being targeted.
Germ line
1. ___________________ gametes or zygotes
gene therapy: corrects the genetic material of _______________.
- Genetic correction is in not inheritable

Somatic cell
2. ___________________ body cell
gene therapy: corrects the genetic material of _______________.
- Genetic correction is inheritable

Cystic fibrosis (囊狀纖維化症)

⚫ recessive
A ____________ genetic disease
⚫ Produce abnormally thick & sticky mucus
=> block airways of lungs, bile & pancreatic ducts
⚫ Traditional Treatment:
1. physiotherapy e.g. slapping the back (5 times/day)
2. pancreatic extract (enzymes) to improve food digestion
3. antibiotics

⚫ Procedure of gene therapy for cystic fibrosis

1. Enclose normal genes in liposomes (vector)
trachea
2. Transfer the normal gene into target cells (epithelial cells of ____________) using
in vivo somatic cell
aerosol inhaler. ( _____________________________ gene therapy)
3. The normal gene in the liposomes may bind with DNA in the nucleus of target cells so
that normal mucus will be produced.
Notes:
⚫ The treatment is effective for a few weeks only => repeated treatment is needed.
⚫ stem cells
For a permanent therapeutic effect, gene therapy should be done on _______________.

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 What potential hazards should scientists consider in the use of gene therapy in treating
genetic diseases?
viral vector
⚫ The _____________________ immune response
may cause severe ____________________________.
random locations
⚫ The gene is inserted at ____________________ in the patient’s genome.
=>This may result in failure of the expression of essential genes & _______ loss of
normal gene products
essential _________________________.
=>The virus may insert regulatory sequences that sometimes activate nearby genes and
cause cancer
_______________________.

 Limitation of gene therapy

recessive
⚫ Gene therapy can be applied to genetic diseases that are ______________ & caused by

loss
__________ of normal gene products but genetic diseases that are dominant & caused

by production of new defective gene products CANNOT be treated by adding extra

copies of the normal gene.

 Bioethics of gene therapy

Ethical issues:

1. Is it acceptable for genetic enhancement?

2. Are we playing God in changing the genetic materials of future generations?

3. Do we have the right to alter the genome of future generations?

Legal issues:

1. How can we obtain informed consent from seriously ill patients or embryos?

2. How can we prevent misuse of gene therapy to produce a ‘perfect’ human race?

Social issues:

1. Would only rich people be able to afford the expensive gene therapy?

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Genetically modified (GM) foods
Potential Benefits of GM food
Yield of food can be enhanced by
⚫ increasing growth rate & size of an individual organism
⚫ producing tomatoes with longer shelf life to reduce wastage & costs
⚫ increasing tolerance of crops to disease, drought, cold or high salinity
⚫ providing resistance to insect pests so that the use of chemical pesticides is reduced
⚫ providing resistance to herbicides so that only weeds are killed when herbicide is applied
⚫ increasing milk production in sheep
Quality of food can be improved
⚫ rice with high level of -carotene, protein & iron
⚫ tomatoes with high level of vitamin C
⚫ coffee with low level of caffeine
⚫ growing leaner meat in transgenic pigs
⚫ sheep milk with low level of bad lipids (saturated fatty acids)
Edible vaccines can be incorporated into food products
⚫ GM potatoes containing edible vaccines are made for people in the Third World.

Potential Hazards of GM food

Potential risks to health
 Potential toxic effects & allergies
 Preventive measures: Perform thorough toxicity & allergy tests on GM foods before
putting into markets & label the food components of GM foods.

Potential risks to environment

 Growing pest resistant plants in the wild leads to reduction in population or even
extinction of some insects including pollinating insects. This reduces the
biodiversity & upset the ecological balance.
 The gene for resistance to herbicide, insect pests or drought might be transferred to
weeds so that they become impossible to be controlled.
 Release of GM organisms (e.g. giant Salmon) to the natural environment may greatly
upset the balance of ecosystem.
 Preventive measures: Use enclosed environment to grow GM organisms, monitor
the change in the environment (e.g. the incidence of gene transfer to wild types).

Religious & ethical concerns

 Some vegetarians do not want to eat food containing animal genes.

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 S5 Biology
E4 Biotechnology
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 What is Genetic engineering?

manipulation
Genetic engineering is the direct human _________________ genome
of an organism's ___________
using modern DNA technology.

 Benefits of genetic engineering

Medicine
⚫ pharmaceutical products
Production of _________________ products using Recombinant DNA technology

⚫ gene therapy
Development of _________________________

⚫ diagnosis
Early & rapid _____________ of certain diseases become possible due to HGP

Agriculture & food production

⚫ productivity
Production of GM crops & animals with higher _______________ quality
& _____________

Environmental protection
⚫ chemical pesticides
Growing pest resistant GM crops reduce the use of _________________________

⚫ biofuels
Production of ______________ from straw using GM cellulose-producing yeast

⚫ Production of GM oil-eating bacteria for cleaning oil spills more effectively & avoiding

using toxic chemicals to clean up the spilled oil

Forensic science
⚫ DNA fingerprinting helps solve crimes.

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Micropropagation (Using tissue culture for propagation of plants)

Culture
medium
containing
sugar, vitamins
& minerals.

Plant
hormones

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AL Bio 05II Q4 (a)

In flowering plants, how do sexual reproduction and cloning by tissue culture differ in terms of
their requirements, processes and outcomes? (11 marks)

Sexual reproduction Cloning by tissue culture

- Parents plants with bisexal flowers which - Meristemic tissues with undifferentiated cells
produce pollen grains carrying male gametes and
Requirements

ovules carrying female gametes

- Involves meiosis for producing pollen grains & ovules - Involves division of undifferentiated cells by mitosis

- Requires pollinating agents for transferring pollens - Requires hormonal treatment (e.g. auxins) to induce
from anther to stigma of flowers ( pollination ) cell division & cell differentiation & organic nutrients
(e.g. sucrose) for growth of cells
Process

- Requires growth of pollen tubes that carry male

gametes to female gametes in ovules. - Requires sterile conditions to prevent growth of the
bacteria & fungi
- Involves fertilization & formation of seeds.
- No fertilization is involved
- Involves germination of seeds to produce new
individuals - Undifferentiated cells develop into shoots & roots
directly

- Offsprings with genetic variations - Offsprings are genetically identical to parents

without genetic variations
Outcome

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Plant Cloning
Advantages of using tissue culture to propagate plants

1. Offspring are genetically identical to the parent

=> desirable features can be preserved.
2. Many daughter plants can be produced in a short time.
3. Disease-free plants can be produced in sterile conditions
=>reduce the loss caused by diseases.

Applications of using tissue culture in propagation of plants

1. to mass produce new varieties resulted from artificial selection/genetic modification &
thus speed up the introduction of new varieties to the market.

2. to mass produce sterile/infertile plants of economic importance.

3. to reproduce endangered plant species that have low reproductive potential e.g. to
reproduce certain orchids whose seeds are difficult to germinate.

Animal Cloning
Applications of animal cloning
1. Agriculture
leaner
• To mass produce livestock with superior characters e.g. __________ meat, higher
milk production, resistance to diseases
inferetile
• To clone ______________ animal e.g. mules

2. Medicine
To mass produce GM animals for the manufacture of drugs e.g. sheep milk with blood
haemophilia
clotting factor for treating _____________________

3. Wildlife Conservation
endangered
To clone ________________ extinct
animals such as Giant panda, or even ___________animals
such as mammoth

4. Pet Industry
To clone pets such as cats & dogs

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Bioethics related to Human Reproductive Cloning

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Ethical issues about Human Reproductive Cloning

⚫ play God
It involves manipulation of life. Human ____________________ in creating life.

This violates the laws of nature.

⚫ embryos
Many __________________ are destroyed but embryo is considered as a life

=> sacrifice of potential life

⚫ abnormal
How to treat the ____________ human clones produced?

⚫ family relationships
Traditional ______________________ upset
may be __________ e.g. Is the cloned the twin or

daughter/son of the nuclear donor?

⚫ Misuse of cloned human individuals for organ reserves, military purposes

=>human as commodity for trading

=>human dignity is lost

⚫ Eugenics (i.e. to intentionally maximize certain traits) may be promoted

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E4 Biotechnology
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Stem Cell Therapy
What are stem cells?
⚫ undifferentiated
Stem cells are _________________ actively dividing
& _______________________ cells. They have
unlimited mitotic cell division. They can differentiate into different kinds of cells.
⚫ There are 2 types of stem cells: embryonic stem cells & adult stem cells.

Therapeutic Cloning in Human

⚫ A somatic cell obtained from a person is fused with an enucleated egg to create an

embryo.

⚫ Stem cells can be obtained from the embryo.

⚫ Stem cells divide to produce more cells which can be induced to differentiate to form

specialized cells, tissues or organs.

⚫ The cells/tissues/organs formed can be transplanted to the person him/herself who

donate the somatic cell for curing some diseases.

⚫ Advantages:
rejection
➢ Such transplantation does not pose any problems of _________________.

➢ Many tissues/organs can be produced to solve the problem of insufficient donation.

Bioethics related to stem cell therapy

Ethical issues:

⚫ embryos
Human ____________ are destroyed to obtain embryonic stem cells. Is it an act of

murder of potential lives?

⚫ trading
It may lead to ____________ of human embryos and the tissues / organs developed

dignity
from the stem cells & human ______________ is lost.

Legal issues:

⚫ How can we ensure that the technique in cloning human embryos would not be used

in human reproductive cloning?

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 How can nerve cells be obtained from bone marrow stem cells?
• Isolate
______________ the bone marrow stem cells.

• Culture
_____________ proliferate
the bone marrow stem cells which _______________ (undergo

mitotic division) to increase in cell number.

• Induce
______________ differentiate
the stem cells to ___________________ into nerve cells.

Limitations of Stem cell therapy

⚫ destruction
Isolation of embryonic stem cells involves ___________________ of human embryos

⚫ rejection
Transplantation of cells may cause immune ________________ in the patients if the

stem cells are obtained from someone else.

⚫ low
Adult stem cells occur in _______________ number.

⚫ culturing
The conditions for ___________________ inducing
stem cells &_________________

differentiation
_______________________ of stem cells into specialized cell types have not been

figured out.

⚫ Some stem cells continue to proliferate after transplantation and become

cancer cells
______________________.

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Human Genome Project (HGP)

Goals of Human Genome Project HGP:
⚫ determine the complete base sequence of human DNA
⚫ determine the location of all the genes in the human genome

Implications of Human Genome Project (HGP)

 Potential Benefits brought about by the HGP

⚫ Better understanding of genetics e.g. how genes control cell activities.

⚫ Improved diagnosis of genetic diseases & screening of unborn babies with certain genetic
diseases (e.g. thalassaemia, Down’s syndrome)
⚫ Improved treatment of genetic diseases (e.g. gene therapy)
⚫ Better understanding of evolution: Comparing the genomes of different organisms helps
build up their evolutionary relationships. The more similar the base sequence of DNA, the
closer the evolutionary relationship of the organisms.
⚫ DNA forensics can be more widely applied.

 Bioethics brought about by the HGP

Ethical:
⚫ Would the diagnosis of an incurable disease cause anxiety? Will more cases of abortion
& suicide be resulted?
⚫ Will this lead to the movement of eugenics? Will this lead to the production of “designer
babies” with special desirable characteristics?
Legal:
⚫ Who owns the personal genetic information?
⚫ Who (e.g. the police, school, insurance companies, employers) can gain access to the
personal genetic information?
⚫ How can we prevent discrimination against people with particular genotypes?
⚫ How can we prevent illegal use of the personal genetic information?
⚫ Do people’s genes make them behave in a particular way? If so, would we have individual
responsibility if we committed crimes? Can the presence of a “violence” gene be used as
evidence to prove someone innocent?
Social:
⚫ How does the personal genetic information affect the public perception of an individual? Will
disclosure of personal genetic data result in the risk for discrimination?
Economic:
⚫ Would money be better spent elsewhere rather than looking for the genetic causes?
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Pre-implantation Genetic Diagnosis (PGD) Technology & Designer Babies

The following diagrams show how to extract one cell from a human embryo at the 8-cell stage
for Pre-implantation Genetic Diagnosis (PGD).

1. What is Pre-implantation Genetic Diagnosis (PGD) technology?

⚫ Produce several fertilized eggs using in-vitro fertilization.

⚫ Allow the fertilized eggs to divide to form an 8-cell embryo in a petri dish.

⚫ Take one cell from the embryo to carry out genetic diagnosis tests.

⚫ Select appropriate embryos to implant in the mothers’ uterus for further development.

2. State the applications of PGD technology.

⚫ To select babies without severe genetic diseases (e.g. thalasaemia) for heterozygous

parents

⚫ To select the sex of babies in order to avoid severe X-linked genetic diseases (e.g.

haemophilia)

⚫ To select healthy babies with compatible cord blood for treating genetic diseases of elder

siblings

⚫ To select babies with desirable sexes.

⚫ To generate designer babies with favourable characters e.g. eye colour, skin colour,

special talents etc.

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3. Are there any ethical & social implications arising from the development of the PGD
technology?
⚫ Are we playing the role of God?

⚫ Embryos which are potential lives will be sacrificed.

⚫ Will the movement of eugenics (only babies with desirable characters are

generated) be promoted?

⚫ Only the rich can afford to select characters for their babies. Will genetic

classes be generated?

⚫ Will there be discrimination on the babies without desirable characters?

⚫ Will gender imbalance in some countries e.g. China, India be more serious?

⚫ Will children scold their parents for not selecting good characters for them?

4. The application of PGD technology to produce “designer” babies is legalized in few

countries only. Which countries are they?

USA, France, Spain

5. Under what circumstances is the selection of the gender of babies lawful in HK?

To select baby girls for avoiding severe X-linked genetic diseases e.g. haemophilia

occurring in the next generation. (Colour blindness which is not a severe genetic

disorder is not included.)

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Possible ways of treatments for Thalassemia

1. Frequent blood transfusion

2. Bone marrow transplantation from unrelated donors

3. Cord blood transplantation from a sibling selected by Pre-implantation Genetic Diagnosis

4. Stem cell therapy using embryonic stem cells from therapeutic cloning / patient’s own
re-programmed skin cells

5. Gene therapy using the patient’s own stem cells from bone marrow

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P24