Clinical genetics milestones

1665

Hooke coins the term cell while looking at cork samples

1674

Antoni van Leeuwenhoek gives the first accurate description of red blood corpuscles and describes nuclei (as globules) for the first time

1833

Botanist Robert Brown describes the nucleus in more detail

1856

Mendel publishes his work on the nature of inherited characteristics

1869

Johann Friedrich Miescher extracts a weak acidic substance (DNA) from white blood cells

1842

Karl Wilhelm von Nägeli observes chromosomes in plant cells

1888

Wilhelm von Waldeyer-Hartz coins the term chromosome leading on from work investigating chromosome morphology and movement during mitosis and meiosis done by his Kiel University colleague Walther Flemming

1889

Hugo de Vries coins the term ‘gene’, suggesting that the "inheritance of specific traits in organisms comes in particles"

1902

Theodor Boveri and Walter Sutton independently develop the chromosome theory of inheritance – cytology and inheritance linked for the first time

1908

Garrod postulates that genetic defects cause inherited disease

1910

Thomas Hunt Morgan links chromosomes to the inheritance of specific characteristics, in this case sex linked traits. These results fused the ideas of Mendel with the concept that chromosomes could contain the hereditary material

1912

Early karyotyping experiments lead Hans von Winiwarter to suggest that humans have 48 chromosomes

1924

Levitsky coins the term ‘karyotype’ – the ordered arrangement of chromosomes. Technical improvements over the next 30 years allowed better stains and preparations to be made so that individual chromosomes could be reproducibly identified

1944

Avery, MacLeod and McCarty identify that a nucleic acid, DNA, is the ‘transforming principle’, carrying the inheritable information. Until then it was thought the transmission molecule was a protein

1949

Sickle cell anaemia described as a molecular disease governed by the rules of inheritance

1953

Watson and Crick suggest a model for the structure of DNA

1956

Human chromosome number corrected to 46 (Tijo and Levan)

1958

Kornberg purifies DNA polymerase

1959

Lejeune, Gautier and Turpin indentify Trisomy 21 (Down’s syndrome)

1961 - 1967

The combined effort of geneticists around the world crack the genetic code

1968

Chromosome banding in plant cells observed, then human chromosome banding described in 1971. Unique banding patterns make it easy to identify individual chromosomes, as well as rearrangements, translocations etc

1969

First in situ hybridisation carried out by Pardue and Gall using radioactively-labelled DNA

1975

Professor Sir Edwin Southern develops the Southern blot - a technique to fix short stretches of DNA to a solid surface, allowing the detection of specific DNA sequences within a sample of interest. This achievement was the pioneering step behind DNA-based microarray technology

1977

Fred Sanger develops the basis for traditional DNA sequencing methods

1982

FISH first used, paving the way for chromosome painting and removed the need for potentially dangerous and difficult-to-use radioisotopes

1983

Kary Mullis discovers PCR

1992

Comparative genomic hybridisation (CGH) first used

1992

Development of next generation, ‘massively parallel’ sequencing commences

1995

First genome of a living organism sequenced (Haemophilus influenzae)

1995

Professor Sir Edwin Southern founds OGT to further develop microarray technology

1996

First microarray technology appears

1998

CGH simplified and resolution increased by fixing target DNA to a slide instead of using chromosome spreads as the target (aCGH born)

2003

Successful completion of the human genome project

2008

First full genome sequence from an individual produced (James Watson)