Dna Timeline

DNA TIMELINE
1859 – CHARLES DARWIN PUBLISHES THE ORIGIN OF

SPECIES
In 1831, Darwin had joined a five year scientific expedition. During his time
away was influenced by Lyell's suggestion that fossils found in rocks were
evidence of animals that had lived millions of years ago. The breakthrough
came when he noted that the Galapagos Islands each supported its own variety
of finch, which were closely related but had slight differences that seemed to
have adapted in response to their individual environments.
1866 – GREGOR MENDEL DISCOVERS BASIC PRINCIPLES

OF GENETICS
Between 1856 and 1863 Mendel conducted experiments on pea plants,
attempting to crossbreed "true" lines in specific combinations. He identified
seven characteristics: plant height, pod shape and colour, seed shape and colour,
and flower position and colour. In his 1866 published paper, Mendel described
the action of 'invisible' factors in providing for visible traits in predictable ways.
We now know that the 'invisible' traits he had identified were genes.
1869 – FRIEDRICH MIESCHER IDENTIFIES ‘NUCLEIN’

In 1869, Swiss physiological chemist Friedrich Miescher first identified what he
called ‘Nuclein’ in the nuclei of human white blood cells, which we know today
as deoxyribonucleic acid (DNA). Miescher's original plan had been to isolate
and characterise the protein components of white blood cell. To do this, he had
made arrangements for a local surgical clinic to send him pus-saturated
bandages, which he planned to wash out before filtering the white blood cells
and extracting their various proteins. However, during the process, he came
across a substance that had unusual chemical properties unlike the proteins he
was searching for, which had a resistance to protein digestion.
1900s – THE EUGENICS MOVEMENT

In the history of DNA, the Eugenics movement is a notably dark chapter, which
highlights the lack of understanding regarding the new discovery at the time.
The term 'eugenics' was first used around 1883 to refer to the "science" of
heredity and good breeding. In 1900, Mendel's theories, which had found a
regular statistical pattern for features like height and colour, were rediscovered.
In the frenzy of research that followed, one line of thought branched off into
social theory and developed into eugenics. This was an immensely popular
movement in the first quarter of the 20th century and was presented as a
mathematical science, which could predict the traits and characteristics of
human beings (which excited everyone).
However, the darker side of the movement came when researchers became
interested in controlling the breeding of human beings, so that only the people
with the best genes could reproduce and improve the species. It was often used
as a sort of 'scientific' racism, to convince people that certain 'racial stock' was
superior to others in terms of cleanliness, intelligence etc etc. It shows the
dangers that come with practicing science without a true respect for humanity.
1900 – MENDEL’S THEORIES ARE REDISCOVERED BY

RESEARCHERS
In 1900, 16 years after his death, Gregor Mendel's pea plant research finally
made its way into the wider scientific community. The Dutch botanist and
geneticist Hugo de Vries, German botanist and geneticist Carl Erich Correns
and Austrian botanist Erich Tschermak von Seysenegg all independently
rediscovered Mendel's work and reported results of hybridization experiments
almost identical to his findings. It took three decades for ‘Mendelian’ theory to
be sufficiently understood and to find its place within evolutionary theory.
1953 – JAMES WATSON AND FRANCIS CRICK DISCOVER

THE DOUBLE HELIX STRUCTURE OF DNA
In 1951, James Watson visited Cambridge University and happened to meet
Francis Crick. Watson remained at the university to study the structure of DNA
at Cavendish Laboratory. Using available X-ray data and model building, they
were able to solve the puzzle. They published the now-famous paper in Nature
in April, 1953 and in 1962 they were awarded the Nobel Prize for Physiology or
Medicine along with Maurice Wilkins.
1983 – HUNTINGTON’S DISEASE IS THE FIRST MAPPED

GENETIC DISEASE
HD is a rare, progressive neurodegenerative disease which usually manifests
itself between 30 and 45 years of age . It's characterised by jerky movements,
psychiatric symptoms, dementia, altered personality and a decline in cognitive
function. As the disease is adult onset, many people have already had children
before they are diagnosed and have passed the mutant gene onto the next
generation. In 1983, a genetic marker linked to HD was found on Chromosome
4, making it the first genetic disease to be mapped using DNA polymorphisms.
However, the gene was not finally isolated until 1993.
1996 – DOLLY THE SHEEP IS CLONED

The world famous Dolly the sheep was the first mammal to be cloned from an
adult cell. The feat was ground-breaking - whilst animals such as cows had
previously been cloned from embryo cells, Dolly demonstrated that even when
DNA had specialised, it could still be used to create an entire organism. Dolly
was created by scientists working at the Roslin Institute in Scotland, from the
udder cell of a six-year-old Finn Dorset white sheep. By altering the growth
medium, the scientists found a way to 'reprogram' the cell, which was then
injected into an unfertilised egg that had had its nucleus removed. The egg was
then cultured to reach the embryo stage, before being implanted into a surrogate
mother. Cloning from adult cells is a difficult process and out of 277 attempts,
Dolly was the only lamb to survive.
1999 – FIRST HUMAN CHROMOSOME IS DECODED

In 1999, an international team of researchers reached a major milestone when
they unravelled for the first time the full genetic code of a human chromosome.
The chromosome in question was chromosome 22, which contained 33.5
million chemical components. At the time, the sequence was the longest
continuous stretch of DNA ever deciphered and assembled. However, it was
only the first deciphered chapter of the human genetic instruction book - the rest
was still to come.
2003 – THE HUMAN GENOME PROJECT IS COMPLETED

History was made in 2003 when the Human Genome Project was finally
completed. The international research project could be described as the greatest
journey ever made – albeit an inwards one. Scientists had achieved a high-
quality sequence of the entire human genome. In 2001, the Human Genome
Project had published a 'rough draft' of the human genome, which included a
90% sequence of all three billion base pairs. Following this, scientists pursued
the second stage of the project – the finishing phase. During this time,
researchers filled in the gaps and resolved DNA features in ambiguous areas
until they had completed 99% of the human genome in final form.
2014 – FURTHER BREAKTHROUGH

Throughout 2014 the world's scientists have continued to develop their
understanding of DNA. Researchers announced in May that they had
successfully created an organism with an expanded artificial genetic code. This
success could eventually lead to the creation of organisms that can produce
medicines or industrial products organically.

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DNA TIMELINE

1859 – CHARLES DARWIN PUBLISHES THE ORIGIN OF

1866 – GREGOR MENDEL DISCOVERS BASIC PRINCIPLES

1869 – FRIEDRICH MIESCHER IDENTIFIES ‘NUCLEIN’

1900s – THE EUGENICS MOVEMENT

1900 – MENDEL’S THEORIES ARE REDISCOVERED BY

1953 – JAMES WATSON AND FRANCIS CRICK DISCOVER

1983 – HUNTINGTON’S DISEASE IS THE FIRST MAPPED

1996 – DOLLY THE SHEEP IS CLONED

1999 – FIRST HUMAN CHROMOSOME IS DECODED

2003 – THE HUMAN GENOME PROJECT IS COMPLETED

2014 – FURTHER BREAKTHROUGH

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