TRANSGENIC ANIMALS, Biotechnologia, Inżynieria genetyczna
[ Pobierz całość w formacie PDF ]IQP-43-DSA-4042
IQP-43-DSA-9492
TRANSGENIC ANIMALS
An Interactive Qualifying Project Report
Submitted to the Faculty of
WORCESTER POLYTECHNIC INSTITUTE
In partial fulfillment of the requirements for the
Degree of Bachelor of Science
By:
____________________ ____________________
Matthew Bradley Joanna Brosius
August 23, 2006
APPROVED:
_________________________
Prof. David S. Adams, Ph.D.
WPI Project Advisor
ABSTRACT
We examined the methods of creating transgenic animals, the reasons for doing
so, and the resulting effect on society. The most common methods of making transgenic
animals are described, and the transgenic animals created to date are categorized by
purpose. Some myths about transgenic animals are dispelled, and the ethical criteria for
determining whether such animals should be made are
established. Three specific
examples of ethical, difficult to determine, and non-ethical creations are analyzed for
illustration.
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TABLE OF CONTENTS
Executive Summary 4
Project Objective 7
Chapter 1 8
Chapter 2 14
Chapter 3 28
Conclusions 39
Bibliography 41
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EXECUTIVE SUMMARY
In the interest of educating the public about transgenic animals and determining
their effect on society, the methods of creating transgenic animals is discussed. The
major types of transgenic animals are listed, with examples of each. Then common
misconceptions will be addressed, and the ethics of transgenic animal creation will be
discussed. In this manner, people who have never heard of transgenic animals might
have a good idea of what they are, and can then form their opinions on fact and not on
fear.
There are many methods for making transgenic animals, but all of them require
making a transgene first. The transgene has three parts: a promoter to dictate the tissue in
which the transgene is to be made, the transgene itself, and a termination sequence. The
most common method of transgenesis is microinjection into the male pronucleus of a
newly fertilized egg. This technique randomly inserts many copies into the male
pronucleus with a micropipette. Another method is known as embryonic stem cell
manipulation, in which the transgene is inserted into the stem cells of the blastocyst via
microinjection, a virus, certain chemicals, or homologous recombination. The advantage
of this technique is the cultured ES cells can be screened for uptake of the transgene,
increasing the efficiency of the process. After the animals are born, they are typically
screened for the transgene, usually via polymerase chain reaction (PCR), or a Southern
blot analysis.
Transgenic animals can be divided into five major categories: disease models,
transpharmers, xenoplanters, food sources, and scientific models. Disease models are
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animals engineered to express the symptoms of a disease. Disease models that have been
made include AIDS mouse, AlzheimerÓs mouse, oncomouse (a model for cancer), and
ParkinsonÓs fly. Transpharmers are dairy animals engineered to express a protein in their
milk. So far, this process has been successful in mice, sheep, goats, and cows.
Xenotransplanters are engineered to allow the transplantation of histocompatable organs
into a human. Human trials have not been approved for this process, even though a
xenotransplanter pig has already been produced. Food sources are food animals
engineered to grow bigger, or simply more efficiently on less food. Superpig, one
example, was a failure due to the pigÓs large list of health issues. Superfish is much more
promising. Scientific models are animals with some transgene introduced to their
genome for the purpose of studying a specific geneÓs, expression, or some biological
process. ANDi is a famous example, and smart mouse, supermouse, youth mouse, and
influenza-resistant mouse also belong in this category.
Is it ethical to create transgenic animals? It is impossible that everyone will agree
with any one thing, so the issue is taken from an animal welfare standpoint, not an animal
rights standpoint which would attempt to defend against the use of animals of any kind in
research. The authors of this IQP argue that changing the genome is not wrong in itself,
but specific applications can be wrong. Changing the genome for the purpose of creating
art (such as the green fluorescent rabbits), and not to increase knowledge or save lives, is
unnecessary. Even though some animals do die in most transgenic experiments, the
numbers of human lives that can be saved far outweighs that suffering, however steps
should be made to make the process more efficient so it results in fewer animal deaths,
and oversights should be in place to minimize animal suffering. Instead of saying that all
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