“Transgenic Animals” Research Ethics

1

Outline

Introduction to Transgenic Animals

Methods of Creation

Examples of TG Animals

Ethical Objections

Religious Views

Conclusion

2

Transgenic Animals

Have DNA from another source inserted into their

genome (GMOs)

Many transgenic animals have been created so far

Currently, no transgenic animal or product is

approved by the FDA for human consumption

3

Why Create Them?

Some of the goals of transgenic animal creation

are:

Improve livestock animals

Use of animals as bioreactors

Production of pharmaceutical drugs

Used as Model Organisms in research4

Creation Principle

Inserting a foreign gene/genes into an animal

The inserted genes are called Transgenes

Genes must be transmitted through the germ

line

So every cell contains the same modified

genetic material5

Creation Methods

There are 4 basic methods:

DNA Microinjection

Retrovirus-Mediated Gene Transfer

Embryonic Stem Cell-Mediated Gene Transfer

Linker Based Sperm-Mediated Gene Transfer

Success rate is very low

6

1) DNA Microinjection

Transfer the desired gene into

the pronucleus of reproductive

cell

Manipulated cell is cultured in vitro to develop embryonic

phase

Transferred to the recipient

female7

2) Retrovirus-Mediated Gene

Transfer

Retroviruses transfer

genetic material into the

host cell to produce

Chimeras

Chimeras are inbred until

homozygous transgenic

offspring are born8

3) Embryonic Stem Cell-Mediated

Gene Transfer

Isolation of totipotent

stem cells from embryos

Desired gene is inserted

into these cells

Recombinant cells are

incorporated into the

host’s embryo9

4) Linker Based Sperm-Mediated Gene Transfer

Sperm carrying the foreign gene, fertilizes the egg where foreign gene is incorporated into the genome

10

Examples of “Transgenic Animals”

11

Transgenic Cattle

Dairy cows carrying extra copies of

two types of Casein genes produce

13% more milk protein

This milk is more nutritious

Currently the milk from these animals

is under FDA review12

EnviroPig

Can digest plant phosphorus more efficiently

Have Phytase enzyme in their salivary glands

Phytic acid in the pig meal is degraded releasing phosphorus which is absorbed by the pig

Pig waste is a major pollutant

13

Transgenic Fish

Salmon/trout can grow up to 6 times

faster than wild-type fish because

they have extra copies of Growth

Hormone (GH) gene

Ornamental GloFish have red, green,

yellow, and orange fluorescent color.

They are available as a pet.14

Transgenic Mice

Most widely used Model

Animal to detect gene

expression

Used in Knock-Out

technology to detect gene

function

15

Transgenic Monkey

ANDI, the first transgenic

rhesus monkey born on

October 2nd 2000, has

GFP gene

Glow in Dark Monkeys also

have GFP and glow under

UV light16

Transgenic Rabbit

Alba, the EGFP (enhanced GFP)

bunny created in 2000 as a

transgenic artwork

Has GFP gene and glows when

exposed to Blue light

17

Transgenic Cats

Cloned transgenic

cats contain red and

green fluorescent

protein

18

Transgenic Goats

Silk gene from spiders

is transferred to

goats

Each goat produces

several grams of silk

protein in her milk

19

Some Ethical Concerns

20

Use of animals in science is a controversial issue

There are some moral or ethical factors contributing

to genetic manipulation

Animal welfare concerns:

Royal Society for the Prevention of Cruelty

to Animals, UK (RSPCA) looking out for

animals, since 1824

Ethical Concerns (cont.)

Use of animals in research causes great suffering to the

animals

Using animals for the production of pharmaceutical

proteins we reduce them to mere factories

Animals should have the same basic rights as human

beings

Each biological species has a right to exist as a separate

identifiable entity21

a) Moral Status of Animals

Pets are a part of family

They should be given respect

They have a sense of pain and pleasure

Moral Code of Ethics should be followed while

using animals in research

22

b) Boundary B/w Natural and Unnatural

There is a boundary constructed between what is

considered ‘natural’ and ‘unnatural’

The crossing of species boundaries is ‘unnatural’

This becomes problematic when higher life forms

are involved; Human-Animal Chimeras

23

c) Consequences of Genetic Modifications

Consequences of genetic modifications might be

positive or negative

Risks are there for human health and environment

24

d) Environment Safety Issues

Modified animals might 'escape' and breed with

other animals, so transferring the new genes to

other populations

Retroviruses might infect other organisms

Wider effects of producing disease-resistant

animals

25

e) Crossing Species Boundaries

Crossing species boundaries is the violation of

God’s laws

This scenario is changing the species concepts

regarding Ecology, Morphology, Phylogeny and

Evolution

26

f) Xenotransplantation Issues

Transplantation of organs from animals (Pigs) to

humans can cause Zoonotic disease such as Mad

Cow Disease

The introduction of these diseases to the human

population could have devastating consequences

27

Ethical Decision Making

Some uses are generally acceptable, often

because their costs (usually welfare, health and

environmental) are perceived as negligible

Some uses are acceptable only where the benefits

are sufficiently great and outweigh any perceived

costs

28

The Banner Report  

In 1995, the UK’s Ministry of Agriculture, Fisheries

and Food delivered Banner Report

It has 3 principles:

Harm of a certain degree ought under no

circumstances to be inflicted on an animal

Any harm to an animal must be outweighed by the

good which is realistically sought

Any harm should be minimized as far possible29

Conclusion

Transgenesis and genetic engineering present difficult

challenges for 21st century scientists and ethicists

The two major considerations are: How much a transgenic animal benefits humans?

How much pain or discomfort does it cause the

animal?

The issue is where you draw the line between human

benefit and animal discomfort30