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Chapter
4 - Designer Life
Human genetics,
genetic engineering, human genome project and biotechnology research
THE GENETIC REVOLUTION by Dr
Patrick Dixon 1993/5
Patents
For Invented Species A
Genetic Word-processor Swapping
New Genes For Old Viruses
To Re-Program Cells Artificial
Insulin From genes Other
Ways to re-program cells How
to Detect Success Writing
out All Human Genetic Code Some
Very Odd Questions Embryo
Experiments
Intro
+ summary Chapter 1
Chapter 2 Chapter
3 Chapter 4
Chapter 5 Chapter
6 Chapter 7
Chapter 8 Chapter
9 References
HOME 40
videos on cloning etc.
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ON GENETIC ENGINEERING
Here
follows an account of what used to be an extremely long and complicated
job: altering genetic code.How do you produce a new species to order?Are
there any limits to the options open to bio-designers?
Patents
for invented species
You
can see how important creating new species is becoming by the intense
legal debate over whether or not a new species can be patented.This
is driven by huge commercial interests.A "master" patent
on a genetically engineered protein has twice been overturned by
British courts recently (150).The European community seems likely
to pass a law treating animals and plants as genetic inventions,
protected under patent (160).Meanwhile US congress has been debating
whether or not human beings can be patented as inventions in a similar
way (170).Genetic research "will produce beings who fall halfway
between what we currently think of as "animal" and "human".It
is unclear on which side of the legal line these creatures will
fall" (170).In April 1988 US Congress eventually decided that
human beings could not for the moment be patented.However there
was no clear definition of what exactly is a human being.After
all, how much genetic code do you have to change?It is all very
well to see you cannot patent a whole human, but as we have seen,
the only thing worth patenting is the contents of a single human
nucleus containing altered DNA.What about human cells altered and
growing in a laboratory flask?If these genes were transplanted into
an egg a new human strain could emerge.Therefore I suspect that
by patenting genetic code in single human cells it may be possible
effectively to patent a human being legally already.
This
is a vitally important area requiring a global legal framework in
our global village.It also requires those writing legislation and
voting on it to be fully informed.This problem of definitions is
going to make effective laws increasingly difficult to write.
Although
such arguments sound absurd, without such legal protection companies
are unwilling to invest heavily.After all, the effect could be identical
to robbing a computer software company by copying a floppy disc
containing an expensive computer program.All you have to do is get
hold of one altered plant or animal and you can clone away new perfect
copies indefinitely (180, 190).
Such
laws are raising immense ethical concerns both sides of the Atlantic
with a group called Patent Concern formed in Europe in early 1991
representing more than 30 environmental, animal, welfare and religious
groups including Greenpeace, the RSPCA, the Genetics Forum and Christian
Aid (200).
In
June 1991 the Nuffield Foundation in the UK set up a new Council
on Bioethics under Sir Patrick Nairne to address moral and ethical
issues.However as we will see, all this activity comes rather late
in the day, following a long way behind what scientists are actually
doing.We will look more closely at the whole issue of law and regulations
in a later chapter (210).
Once
laws have begun operating in various countries (220) giving companies
the right to own different species of plants or animals we have
then also begun to see massive legal disputes between companies
trying to prove who first created the new genetic code for a new
plant or animal (230).However patent protection is one thing, having
the licence to manufacture or to sell is quite another with some
countries proposing or implementing bans or delaying permission
pending investigations (240), even where patents have been formally
registered.This whole area is becoming increasingly political (245).
A genetic
wordprocessor (Return
to top)
Assuming
for the moment we lay aside all ethical and legal debates, there
are several approaches we can take to designing life:they all work
by treating genetic code as a language text on a computer in exactly
the same way that this book was programmed onto a word-processor.
With
a word processor I can alter this book in various ways:
I
can delete text and retype just the bits I want to change. I can
of course wipe out the whole thing and retype it from scratch.There
is another interesting feature of the word processor which is to
borrow sections of text from elsewhere; to insert the text from
a previously published magazine article into a certain chapter,
and then to trim out the bits I no longer need.
All
these same techniques can be used by the genetic writer: writing
from scratch works all right if the piece is short and you know
what you are doing.Deleting or inserting a minor change is also
possible.Inserting a large chunk of genetic writing from elsewhere
(another organism) also works well, and is the simplest thing to
do.After all, at least you know the code inserted has some biological
effects in at least one species.
However,
the genetic writer still suffers from a massive disadvantage.The
only parallel I can give is a magazine editor who speaks only a
few words of Arabic having to assemble and edit a weekly Arabic
magazine.On his table he has around 150 pieces of writing of varying
lengths and an English two sentence summary of the rough contents
of each piece.
He
has no-one to help him except a proof reader who tells him if it
makes sense or not, but not what the errors are or how to correct
them.He has a dictionary of less than 30 words - nothing else.
There
is one very time-consuming way out of this mess.The editor can take
steps to identify the most important sentences in each section of
text by cutting the text up into many different pieces, preferably
with obvious markers such as pictures still attached and try them
out - asking what each story now contains. By this method he may
eventually learn to recognize key words and phrases and what they
mean.More importantly he may be able to assemble the magazine very
quickly because he links in his mind particular pictures or illustrations
with various key items so he does not have to translate them each
time.
Swapping
new genes for old (Return
to top)
The
genetic editor uses a range of similar techniques to swap new genes
for old ones (250).Let's take for example the problem of the diabetic.Insulin
is needed by the body to use sugars properly.In those with diabetes,
the Langerhans cells in the pancreas no longer produce sufficient
insulin.Without insulin sugar is absorbed into the blood from food
but does not cross cell walls so people lack energy, cannot think
clearly and can even die.Insulin can be extracted form the pancreas
of cows or pigs but it is impure and the body reacts to it.Nevertheless,
such extracts have successfully treated diabetics for many years.
Can
we find the genetic code for insulin?Can we then programme new cells
to make pure human insulin?The first job is to find the genetic
writing for insulin.This is like looking for a needle in a massive
haystack.
One
thing we can try is to cut up the entire genetic code into thousands
of pieces of varying lengths and insert pieces into bacteria to
see what happens.
To
do this we need special biological machines called enzymes.Enzymes
are what digest dirt in many washing powders.Enzymes either split
chemical structures into two or join them together.We can only analyze
genetic code if we have a very large number of copies of the piece
to be read.Therefore we need a reliable duplicating machine.This
can either be achieved in cells or externally.Rapid progress now
means that this complicated process can be completely automated
in the test tube (260).
Once
the fragment of genetic code has been copied sufficiently and then
separated we need to find a vehicle to carry one piece at a time
into bacteria.Bacteria are simple single-celled organisms that live,
breathe, sometimes move, and produce not only gases such as carbon
dioxide but often poisonous substances as well.The type of bacteria
usually used in experiments is called E.coli, a relatively harmless
germ that lives in the gut and helps us digest our food.
Viruses
to reprogramme cells (Return
to top)
Bacteria
like humans get all kinds of viral infections.Bacterial viruses
are called plasmids and work by transferring new genetic code from
one bacteria into another (270).Human viruses do the same.The AIDS
virus, HIV, for example inserts new genetic code into the soldier
cells (T4 white cells) that your body uses to fight infection.When
the genetic code is added to the chromosomes in the nucleus the
soldier cell effectively loses the instruction sheets on fighting
infection and gains instruction sheets on making new virus particles.
Plasmids
have been studied a lot in the laboratory (280).We know a lot about
them because bacteria pass pieces of genetic messages to each other
all the time in the human gut using plasmids.
If
a few bacteria become resistant to a new antibiotic, the genetic
secret of how they manage it quickly travels to other gut bacteria
so the other types of bacteria also quite literally learn new ways
of avoiding damage from the antibiotic (290).This is a very important
reason why many doctors now try to avoid using antibiotics unless
they really need to - we do not want to land up educating a load
of plasmids!
Plasmids
do in fact exist very widely in the environment and their effects
are seen particularly in places where bacteria are adapting to new
habitats or where their environment is changing.The viruses are
particularly seen in excreta from man and animals where antibiotics
have been used, where antibiotics find their way into sewage (often
excreted unchanged in urine or as a result - say - of disposing
of unwanted medicines down the drain), or from industrial contamination.Industrial
discharges containing toxic heavy metals will also induce plasmid
led adaptations (295).
Incidentally,
industrial wastes produced as a side-product of the chemical industry
are becoming more and more of a problem to dispose of safely.Increasingly
the industry is looking to genetic engineers to produce bacteria
to eat these toxic substances (296), breaking them down into non-toxic
residues (297).
One
example recently has been the problem of what to do with tens of
thousands of East German cars called Trabants.These were produced
prior to the collapse of the Eastern bloc with the opening of travel
restrictions to the West.Much loved by some and hated by others,
these primitive two cylinder cars were are highly wasteful of petrol
and fill the air with higher than normal concentrations of polluting
gases.
However
the biggest problem of all is presented by what they are made of.Unlike
most cars in the West, the bodies of Trabants are made of a synthetic
resin which does not rot or rust and cannot be burned because burning
releases highly toxic gases.A recent newspaper report claimed that
genetic engineers were working on a new type of microbe to eat these
vehicles, turning the bodies into a harmless sludge.These changes
will also be made using plasmids.
Returning
to the problems of plasmids being released or multiplying in the
environment, we find that prior to the antibiotic revolution in
farming and medicine, plasmids were relatively uncommon.Now their
distribution as bacterial viruses is vast in both terrestrial and
aquatic environments (300).
Recent
research off the coast of California has shown these viruses are
now multiplying in their tens of billions to form such concentrations
that even in seawater, their density is enough to transfer data
from one bacterium to another (305).
It
is a relatively simple matter to place pieces of genetic writings
into plasmids.Enormous advances have been made in the last two to
three years (310).Plasmids can then be mixed with E. coli bacteria
or with other bacteria.Very occasionally the results can be spectacular
although this is very much a hit and miss approach.
Bacteria
can be separated easily by taking a metal probe and dipping it into
a solution containing bacteria.The probe is then scraped in a zigzag
pattern across a small dish containing a special jelly called agar.The
dish is then placed in an incubator at blood temperature for several
days.Towards the end of the zigzag pattern the number of bacteria
still left on the probe was so low that only a very few bacteria
landed up on that part of the jelly.Each will now have multiplied
rapidly to form a small sticky mound, a few millimetres in diameter.Each
of these mounds is an individual colony from an individual bacterium.
If
we had added a special marker - such as a piece of code for antibiotic
resistance - to the piece we are looking to test then we will immediately
be able to spot the one in a hundred which have been successfully
reprogrammed because those will be the only colonies that tend to
grow in agar mixed with antibiotic.
These
colonies can then be tested for any unusual properties which will
tell us what the piece of genetic code inserted is designed to do.
Artificial
Insulin from genes (Return
to top)
After
enough attempts you may discover an extraordinary event taking place:one
of the reprogrammed bacteria in your test tube may have learned
to make a human substance - maybe even something useful like insulin.
Such
an event only has to happen once in a long time to keep the scientists
happy for years.After all, this reprogrammed bacterium can now be
cultured separately.Each time it divides it produces another insulin-producing
organism.By filling a big brewery-style vat full of warm liquid
and food we can start off a process as large as brewing beer except
that in this case we are brewing insulin.It will need careful extraction
and purifying from other parts of the brew using genetically engineered
monoclonal antibodies (p
), to remove any dangerous substances from the mixture.
By
the late 1980's bacteria were already being used routinely to produce
the first genetically engineered insulin.This insulin has now almost
entirely replaced cow and pig insulin (320).
Many other remarkable successes have followed for example
producing vast quantities of fragments of Hepatitis B virus in a
big fermentation vat, using a yeast called saccharomyces (330).These
particles are harmless and can be injected as a vaccine for Hepatitis
B.Industrial scale production of genetically engineered products
is now commonplace (340).
Other
ways to reprogramme cells (Return
to top)
Scientists
have now perfected a somewhat different method for changing genetic
code in mammal cells called eletroporation.This uses a high voltage
electrical discharge to make cell walls "leaky" so that
genetic code (DNA) in the surrounding liquid can find its way into
the cell (350).Around one in a hundred cells can be "transfected"
in this way (360).This has the advantage over a number of other
methods of reconstructing animal and plant cells - these include
microsurgery, the use of polyethylenglycol with a virus type called
sendai (370), or a technique known as erythrocyte ghost fusion (380).Reprogrammed
mammal cells can either be used like bacteria, growing them in a
flask in a factory, or they can be transplanted back, turning the
whole animal into a factory production unit.This has been tried
in mice, reprogramming skin cells to produce Factor 9, needed to
treat a blood disorder related to haemophilia (390).Bacteria are
only suitable for producing relatively simple substances.More complicated
proteins require the extra machinery in mammal cells (400).
These
experiments have basically worked through the "cut and paste"
principle: cutting up a piece of text with a pair of scissors, shoving
it into a different book altogether and seeing how it reads.Similar
progress has also been made on reprogramming yeasts (or fungi) (410).
With
bacteria, the results are usually obvious fairly quickly but when
genetically altering plants and or animals, it can take months to
tell if you have been successful or not.The plant or tree has to
grow to produce a crop or fruit you can test for example.However,
there are ways of shortening the whole process.If you can find a
marker, as we have seen in the earlier example, you are more than
half way there.
How to
detect success (Return
to top)
Markers
are some pieces of writing that are on the same strip of code or
very close to it, that produce an immediate result.For example,
suppose the genetic code from one type of rosebush with ugly flowers
programmes it to produce a natural substance which kills greenfly.Suppose
also that you notice that a nearby part of the code also tends to
turn new rose shoots bright yellow.
When
the experiments are complete, a quick inspection of the greenhouse
can show you the plants with yellow shoots which have almost certainly
taken all the new code, also producing greenfly-resistant roses.Another
example currently being used is a gene which gives human cancer
cells multidrug resistance to therapy.This is easy to spot if it
is taken up by cells in the laboratory.If joined to a less immediately
obvious gene we can tell rapidly if reprogramming with the second
gene has been successful (420).We do this by exposing cells we hope
have been reprogrammed to the toxic chemicals.Those that survive
are worth looking at further.
There
is another possibility:how about actually learning to speak the
language of the nucleus?It would greatly assist the editor and would
mean he would be able to write genetic code of his own instead of
always editing text from elsewhere.
We
have learned a few words and phrases: for example we now know of
course the exact sequence that programmes for insulin (430) and
that for Factor 8 needed by those with haemophilia.The Factor 8
code, analyzed in 1984 was an extraordinary feat since this massive
gene was a full 0.1 percent of the total X chromosome (440).We
have also now identified and analyzed the giant Duchenne muscular
dystrophy gene which causes muscle wasting (450).We have also recently
identified the gene that causes the most common type of inherited
mental handicap: the fragile X syndrome.This affects one in a thousand
children, almost all boys, and causes mental retardation (455).
Writing
out all human genetic code (Return
to top)
But
now a much more ambitious task is under-way.This task is one of
the most daunting scientific challenges ever attempted.The task
is to write out the entire human genetic code, letter by letter
from start to finish.The code as a whole is known as the human genome
and as we have seen it is millions of characters long.Many hundreds
of research scientists in a number of countries are racing against
time to crack this code of human life.When it is done they think
they will be able to begin to work out a vast dictionary showing
the meaning in terms of function of each small word or sentence.The
process is likely to take less than fifteen more years.It is an
expensive business however.The Cystic Fibrosis Foundation alone
spent ?74 million on the Human Genome Project in the UK between
1985 and 1989 (460).As a direct result we now know the exact sequence
of code for the fibrosis gene, after processing and analyzing almost
300,000 letters of genetic writing.The discovery has huge implications
for diagnosis and treatment (462).
This
vast project only sequenced less than 0.01 percent of the total
human genome of three billion characters.Therefore the whole genome
will cost around ?650,000,000 to translate.Who will own the information
(470)?Such progress raises urgent ethical questions which we will
look at later (475).
Reading
genetic code is immensely complicated - or rather it used to be.Sequencing
work done by hand used to take months - just to decipher several
thousand letters of code.Now a similar process takes less than a
week and is almost entirely automatic -thanks to the computer technology
of the previous decade.
This
whole field is known as microchemical instrumentation (480), and
similar machines can now write code as well as read it.
Effectively
you can type in a sequence up to 50 characters long, press a button
and come back in a few hours.The genetic code will be assembled
and waiting for you.The machine is only the size of a desktop computer,
and is available by mail order advertised in many scientific magazines.The
process used to be very laborious and experimental (490).
Kits
to join genetic code strips together can also be bought cheaply,
together with genetic code duplicators.These kits are not much larger
in size than five copies of this book laid on top of each other.You
can see these items on show at the Science Museum in London and
even decode part of a gene yourself using a computer simulation
(492).A new computer programme is also available now to help design
new plasmids and to facilitate in cell cloning operations.The programme
is called Clone 3 (493). New methods are being developed continually
to speed up and simplify the process from gene sequencing to reprogramming
to the end result of protein production (494).
One
of the quickest ways to duplicate genetic code is known as the polymerase
chain reaction (495).This has revolutionised DNA technology as it
allows virtually any nucleic acid sequence (DNA) to be generated
in the test-tube in large amounts.The DNA produced is pure and the
procedure is much faster than using cells to reproduce it.It is
also about to become an important diagnostic tool in microbiology.Practically
even a single bacterium, virus particle or parasite can be detected
by it (495), and it can also be used in forensic medicine to analyse
samples or in archaeology to analyse plant or animal remains (495).
A
complete directory of all genes located in humans is now in its
ninth edition and has 5,300 entries of which 2,000 genes have been
mapped to specific sites on chromosomes (500).
The
implications will be beyond measure:if you consider the genetic
code as a massive long line of on/off switches with labels, within
the next few years we should be able to engineer small changes precisely
where we want and know where the result will be.In the US the National
Institute of Health (NIH) has set aside ?150 million for the Human
Genome Project over the next two years, headed up by James Watson,
co-discoverer of DNA structure in 1953.He thinks it will take 15
years at a cost of ?2,000,000,000 (510).
The
Director of Research at the Imperial Cancer Research Fund recently
estimated that if the cost were spread over 15 years, split between
Europe, the Americas, Japan and Asia would give Europe a bill of
?30 million a year of which the UK might need to contribute ?10
million a year (520).The Human Genome Organisation has 250 members
from all over the world.
Some
very odd questions (Return
to top)
It
allows us to ask some very interesting questions about patterns
of life: questions that may at first sight appear bizarre but which
are of fundamental importance to us in designing new species.Can
farmers produce better animals for eating (525)?Do elephants have
to be so large - can't we programme miniature ones?Can we programme
into chimpanzees a portion of human code that gives them a limited
spoken language capability and better reasoning powers?Can we use
them as intelligent sub-human clones for difficult and dangerous
tasks instead of incredibly expensive and limited robots.Before
we know where we are we are back into debating what constitutes
a human being: how much human code do you need - 5%, 10%, 55%?Is
it just appearance?How human do you have to look?The issues do not
just relate to patents but more importantly, to ethical licensing.
To
even ask the questions is to risk arousing the most intense controversy
(525).
By
comparing the genomes of different people (530) and different animals
it should be possible to build up a vast vocabulary accurately.The
interesting thing is the unity of the genetic code: a yeast cell
uses exactly the same coding language as a human.Therefore the same
technology works for reprogramming cells from humans or other mammals
(535).
One
of the difficulties in reading the code and knowing what each piece
does is that large amounts of code are only used in the developing
embryo.For example, the instructions to help form the eye will only
be triggered in some cells in an embryo at one critical point in
development.For the rest of the entire period from egg fertilization
to death of the animal, that strip of code is locked away, turned
off or inactive.The secrets of these areas of code are perhaps the
most fascinating parts of life itself.
Why
does the human hand produce five fingers and not six?Which set of
genes tells fingers to produce nails on the top and not along the
bottom?Could a human have four sets of arms and two pairs of hands?Occasionally
drugs given during pregnancy produce such events - usually because
of confusing cells as to where they are rather than because of direct
genetic damage.
Embryo experiments
(Return to top)
Scientists
are busy altering genetic code in fertilized eggs and watching to
see what happens to the embryos.In drosophila insects the genes
have been identified for early body formation, and adult skin production
(540).We can expect similar progress in mice and monkeys.It will
be very tempting for some to try the same with surplus fertilized
human eggs resulting from fertility treatments such as GIFT.Many
of these techniques involve giving a special drug to a women, stimulating
her ovaries to produce up to twenty eggs instead of only one.These
are then removed in a minor operation.
In
many centres, all are then exposed to sperm and observed under the
microscope to see if they are dividing (i.e. successfully fertilised).Some
eggs (two to six) are then implanted in the womb in the hope that
at least one will implant successfully.Quite often none do although
sometimes several succeed, and the result is triplets or quadruplets
or quintuplets or sextuplets.The big ethical question is what to
do with the spare embryos, which can be frozen indefinitely.Many
are being used in experiments, most of which involve allowing them
to grow and develop in the laboratory.
At
this point you may like to pause for yourself to consider some of
the more bizarre possibilities: an animal with the flesh of a cow,
the milk of a human mother, the wool of a lamb, the tolerant digestive
system of a pig (550).You can design one of your own (560).
This
may all seem rather far fetched to you.Even as long ago as 1987
(light years ago in bioengineering progress) it was reported that
artificial chromosomes were being manufactured for yeast cells with
the prediction that production of entire chromosomes for more complex
organisms would be possible in the near future (570).
I
leave the final word here to a well known writer - "If human
blood cells can grow outside the human body, why not human bone
cells, muscle cells and nerve cells?And eventually all of them together
functioning as a single living organism" - words written long
ago in her novel "Frankenstein: a modern Protheus" by
Mary Shelley.However the thought has recurred (550).
AUTHOR's NOTE: PRESS
HERE FOR LATEST NEWS ON THESE ISSUES
Patents
For Invented Species A
Genetic Word-processor Swapping
New Genes For Old Viruses
To Re-Program Cells Artificial
Insulin From genes Other
Ways to re-program cells How
to Detect Success Writing
out All Human Genetic Code Some
Very Odd Questions Embryo
Experiments
Intro + summary
Chapter 1 Chapter
2 Chapter 3
Chapter 4 Chapter
5 Chapter 6
Chapter 7 Chapter
8 Chapter 9
References
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