Biotechnology has been around for centuries
as people have used microorganisms to make beer, wine, bread, yoghurts
and cheeses. But since the beginning of the 20th century, the nature
of biotechnology has changed dramatically. This timeline shows you
some of the developments which have led to the point where manipulating
the DNA allows us to change the very nature of life itself.
| 1900 |
Higo Marie De Vries, Karl Franz Joseph Correns and Erich
Tschermat von Seysenegg rediscover Gregor Mendel's work on
genetics, which has been ignored for 40 years. They each rediscover
his laws for themselves, search the literature and when they
find Mendel’s work they each, in a very unselfish gesture,
give Mendel the credit.
Drosphila (fruit flies) are used in early studies of genes. |
| 1902 |
Walter Sutton states that chromosomes are paired and may be
the carriers of heredity. |
| 1905 |
Clarence McClung shows that female mammals have two X chromosomes
and males have one X and one Y. |
| 1906 |
The term genetics is introduced. |
| 1907 |
Thomas Hurst Morgan starts working on fruit flies to prove
that chromosomes have a role in hereditary and to confirm mutation
theory. This work will lead to a much deeper understanding of
the mechanisms of hereditary. |
| 1909 |
The terms gene, genotype and phenotype
are used for the first time. |
| 1911 |
The first chromosome maps are developed. |
| 1926 |
Hermann Muller discovers that X-rays cause genetic mutation,
through his work with fruit flies. |
| 1941 |
George Beadle and Edward Tatum develop the idea that each
gene controls the development of one enzyme. |
| 1944 |
Oswald Avery, Colin MacLeod and Maclyn McCarthy show that
DNA is the hereditary material for most living organisms. |
| 1951 |
The first embryo transplants for cattle are performed. |
| 1952 |
A calf is produced using semen that has been frozen before
it was used. |
| 1953 |
In London Rosalind Franklin and Maurice Wilkins carry out
X-ray crystallography studies of DNA.
James Watson from the USA and Francis Crick from England
develop the double helix model of DNA which explains the way
in which this massive molecule can carry and transmit the
hereditary information in living organisms. |
| 1959 |
Japanese scientists make a discovery which will be vital in
the development of genetic engineering. They find resistance
to antibodies in Shigella dysenteriae is passed from
one bacterium to another by small circles of DNA known as plasmids,
separate from the normal DNA. |
| 1964 |
Charles Yanofsky and Sydney Brenner prove that the order of
bases in DNA coincides with the order of amino acids in proteins.
This is a vital step in understanding how proteins are made
in the body. |
| 1967 |
Charles Caskey, Richard Marshall and Marshall Nirenberg show
that identical messenger RNA is used to form identical amino
acids in bacteria, toads and guinea pigs, leading to the suggestion
that the genetic code is a universal information system for
all life forms. |
| 1970 |
Werner Arber, a Swiss scientist, makes a discovery which
has far reaching effects for genetic engineering. He finds
that bacteria defend themselves against viruses by cutting
the virus DNA using special restriction enzymes. (These enzymes
are now widely used in the new DNA technologies.)
The first gene is synthesised. |
| 1971 |
Daniel Nathans and Hamilton Smith develop enzymes which break
DNA at specific sites – another step towards
genetic engineering. |
| 1973 |
A calf is produced from a frozen embryo for the first time.
Stanley Cohen and Herbert Boyer show that DNA molecules can
be cut with one type of enzyme, joined together again with
another type and reproduced by inserting them into the bacteria
E. coli. This is the beginning of the science
of genetic engineering. |
| 1974 |
Some scientists call for a halt in the development of genetic
engineering until the implications of what it might lead to
are better understood. |
| 1978 |
Louise Brown, the first ‘test-tube baby’ is born.
She was the result of in vitro fertilisation, where
her parents gametes joined outside of the mother’s body
and the developing embryo was then returned to the uterus to
develop normally. |
| 1979 |
Sir Walter Bodmer suggest a way of using DNA technology to
find gene markers to show up specific genetic diseases and their
carriers. |
| 1980 |
Louise Clarke and John Carbon clone a gene involved in cell
division in yeast cells. |
| 1981 |
Chinese scientists successfully clone a fish, a golden carp |
| 1982 |
A gene for rat growth hormone is successfully transferred
into mice, which grow up to twice their normal size because
of the extra growth hormones they are producing.
The first human insulin made by bacteria as a result of
genetic engineering is marketed. |
| 1983 |
James Gusella finds a genetic marker for Huntington’s
disease.
The polymerase chain reaction
is invented by Kary B Mullis. |
| 1984 |
Charles Sibley and Jon Ahlquist use DNA to show that humans
and chimpanzees are more closely related to each other than
either of them are to any of the other great apes.
Alec Jeffries discovers the technique of genetic fingerprinting
which can be used to establish family relationships and to
identify criminals.
Sheep embryos are successfully cloned. |
| 1985 |
Scientists find a gene marker for cystic fibrosis on chromosome
number 7.
Human growth hormone produced by genetically engineered bacteria
is made available for treatment of children with growth problems. |
| 1986 |
The first monoclonal antibodies are used to help in organ
transplants.
Genetically engineered plants are grown outside in field
trials for the first time in the USA. The plants are genetically
altered tobacco. |
| 1987 |
A crime suspect is convicted on the evidence of genetic
fingerprinting in the UK.
David Page and his colleagues find a single gene on the Y
chromosome which seems to control the sequence of events which
leads to an embryo developing testes instead of ovaries – in
other words, a gene for maleness.
The first outdoor tests on a genetically engineered bacterium
are allowed. It inhibits frost formation on plants. |
| 1988 |
A patent is given for a genetically engineered mouse. |
| 1989 |
The human genome project
is set up, a collaboration between scientists from countries
around the world to work out the whole of the human genetic
code.
Human gene therapy is attempted successfully for the first
time. A modified virus is used to carry the healthy gene for
a particular enzyme into the cells of a woman with a very
weak immune system. It provides her with a normally functioning
system, but only temporarily – the treatment
has to be repeated regularly. |
| 1991 |
Tracey the first transgenic sheep is born. She has human genes
which enable her to produce human protein in her milk. This
protein is extracted and it is hoped it may help relieve the
symptoms of people suffering from cystic fibrosis and emphysema. |
| 1992 |
The first liver xenotransplant
from one type of animal to another is carried out successfully.
Tests for cystic fibrosis and haemophilia in foetuses are
developed.
|
| 1994 |
The FLAVRSAVR tomato becomes the first genetically modified
food sold in the UK. The advantages claimed include resistance
to bacterial and fungal attack, a higher ratio of solids to
water in the fruit and better taste. Concern is expressed about
the marker gene used, which confers resistance to the antibiotics
kanamycin and neomycin. |
| 1995 |
The bacterium Haemophilus influenzae is the first
living organism in the world to have its entire genome sequenced.
Ian Wilmut clones several lambs from the cells of a nine-day
old embryo lamb. |
| 1997 |
Dolly the sheep is born. She is produced by Ian Wilmut
and his team at the Roslin Institute near Edinburgh. She has
been cloned from an udder
cell of an adult sheep and the egg implanted into a completely
different sheep.
Polly the sheep born later the same year is the first genetically
engineered sheep to be cloned. |
| 1998 |
Dolly the sheep gives birth to her own lamb, showing she
is capable of normal reproduction.
James Thomson at Wisconsin and John Gearhart in Baltimore
each develop a technique for culturing embryonic
stem cells. This promises enormous potential for forming
new organs for transplants without problems of rejection.
|
| 1999 |
Healthy cloned goats are produced for the first time. They
contain an engineered human gene so that they can make an
anti-clotting factor in their milk.
A US firm buys the technology used to clone Dolly in a bid
to clone cells from patients to produce new organs for transplanting
in therapeutic stem cell
cloning.
|
| 2000 |
Cloned pigs are born for the first time in work done by Alan
Coleman and his team at PPL, the Edinburgh-based company responsible
for Dolly the sheep. |
| 2003 |
The sequencing of the human genome is completed, two years
ahead of schedule. |
| 2003+ |
Developments in biotechnology are coming thick and fast. Many
of them involve the development of new medicines and diagnostic
tests which are not only making it possible for more and more
diseases to be identified quickly and accurately but also for
some of them to be treated more effectively than ever before. |