John Marion Thoday FRS (30 August 1916 – 25 August 2008) was a

British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories, and Crown Dependencies. ** Britishness, the British identity and common culture * British English, ...

geneticist A geneticist is a biologist or physician who studies genetics, the science of genes, heredity, and variation of organisms. A geneticist can be employed as a scientist or a lecturer. Geneticists may perform general research on genetic processe ...

. He was the son of the

botanist Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek wo ...

David Thoday. He was

Arthur Balfour Professor of Genetics The Arthur Balfour Professorship of Genetics is the senior List of Professorships at the University of Cambridge, professorship in genetics at the University of Cambridge, founded in 1912. It is thought to be the oldest Chair of Genetics in the Engl ...

Cambridge University , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...

between 1959 and 1983 and was elected a

Fellow of the Royal Society Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the judges of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural science, natural knowledge, incl ...

in 1965. Thoday was born in

Chinley Chinley is a rural village in the High Peak Borough of Derbyshire, England, with a population of 2,796 at the 2011 Census. Most of the civil parish (called Chinley, Buxworth and Brownside) is within the Peak District National Park. Historicall ...

Derbyshire Derbyshire ( ) is a ceremonial county in the East Midlands, England. It includes much of the Peak District National Park, the southern end of the Pennine range of hills and part of the National Forest. It borders Greater Manchester to the nor ...

, and educated at

Bootham School Bootham School is an independent Quaker boarding school, on Bootham in the city of York in England. It accepts boys and girls ages 3–19, and had an enrolment of 605 pupils in 2016. It is one of seven Quaker schools in England. The school ...

,''Oxford Dictionary of National Biography''
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York York is a cathedral city with Roman origins, sited at the confluence of the rivers Ouse and Foss in North Yorkshire, England. It is the historic county town of Yorkshire. The city has many historic buildings and other structures, such as a ...

, followed by

University College of North Wales , former_names = University College of North Wales (1884–1996) University of Wales, Bangor (1996–2007) , image = File:Arms_of_Bangor_University.svg , image_size = 250px , caption = Arms ...

at Bangor, and then

Trinity College, Cambridge Trinity College is a constituent college of the University of Cambridge. Founded in 1546 by Henry VIII, King Henry VIII, Trinity is one of the largest Cambridge colleges, with the largest financial endowment of any college at either Cambridge ...

. During

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

he served in the

RAF The Royal Air Force (RAF) is the United Kingdom's air and space force. It was formed towards the end of the First World War on 1 April 1918, becoming the first independent air force in the world, by regrouping the Royal Flying Corps (RFC) and ...

as a photographic intelligence officer. His research from 1947 has been largely concerned with the causes and functions of intraspecific

genetic variation Genetic variation is the difference in DNA among individuals or the differences between populations. The multiple sources of genetic variation include mutation and genetic recombination. Mutations are the ultimate sources of genetic variation, ...

, on the nature of continuous genetic variation and on the effects of selection on such variation. He has published an important thesis on the meaning of biological progress in

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

and the role of genetic variation in determining long term fitness. He has pioneered a method for the location on

chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...

s of

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

s mediating continuous variation, and showed (contrary to accepted theory) that the genes at different loci affected the quantitative character in qualitatively different ways. He has pioneered experiments into

disruptive selection Disruptive selection, also called diversifying selection, describes changes in population genetics in which extreme values for a trait are favored over intermediate values. In this case, the variance of the trait increases and the population ...

(selection in the same population for both extremes and against intermediates), and (again contrary to theoretical expectation), showed such selection could be extremely effective, increasing variance, establishing and maintaining polymorphisms, and, if the selected individuals were allowed to choose their mates, dividing the population into two partially isolated parts, something which is a step towards

speciation Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within ...

References

External links

Obituary in ''The Telegraph''

Obituary in ''The Times''
* http://www.emma.cam.ac.uk/teaching/fellows/display/index.cfm?fellow=67 * http://www.professorjohnthoday.com/publications.html Professor Thoday's full publications listing. * http://www.professorjohnthoday.com/ Professor Thoday's personal web site. 1916 births 2008 deaths English geneticists Fellows of the Royal Society Alumni of Trinity College, Cambridge Fellows of Emmanuel College, Cambridge People educated at Bootham School Royal Air Force officers Royal Air Force personnel of World War II Arthur Balfour Professors of Genetics Alumni of Bangor University {{geneticist-stub