Lucien Cuenot
Encyclopedia
Lucien Cuénot was a French biologist. In the first half of the 20th century, Mendelism was not a popular subject among French biologists. Cuénot defied popular opinion and shirked the “pseudo-sciences” as he called them. Upon the rediscovery of Mendel's work by Correns
, Devries, and Tschermak, Cuénot proved that Mendelism applied to animals as well as plants.
and two “distases” enzymes. The pigment (if present) is acted upon by the enzymes to produce black or yellow colour. If no pigment is present the result is an albino mouse. Cuénot studied the offspring of various crosses between mice and concluded that these “mnemons” or genes
were inherited in a Mendelian fashion.
Subsequently, Cuénot was the first person to describe multiple allelism at a genetic locus
.
He also described a lethal mutation
in the mouse agouti locus at a time when such a mutation was unheard of.
Some scientists who were famous in Cuénot's day such as William Bateson
, the man credited the “one gene one enzyme” hypothesis never recognized Cuénot's discovery that certain traits arose due to the presence or absence of an enzyme. Archibald Garrod
suggested in the early part of the 20th century that certain diseases occurred in the absence of an essential enzyme in a biochemical pathway and that these diseases were inherited as Mendelian recessives. Garrod failed to mention Cuénot in his work. At this time, there was widespread difficulty with reconciling genetics and biochemistry.
Failure of Bateson and Garrod to mention Cuénot's pioneering work on the one gene-one enzyme hypothesis
does not take away from the fact that it was pioneering work. Such failure to credit pioneering work would constitute scientific misconduct
in the present day. That Cuénot's articles were in French may be the reason for Bateson's and Garrod's insular view.
Bateson's failure to mention Cuénot's work may be because Bateson did not like Cuénot. Batson did record in a letter that on meeting Cuénot in December 1905 Cuénot "insisted that the yellow colour of mouse fur was dominant to agouti (grey)" fur colour, and that Bateson found Cuénot "a dull man". There may have been some professional jealousy, as Bateson did receive a letter from Hurst in which he was urged to "read and digest the new Cuénot", work which explained some results in the field of mouse genetics, results which had been confusing for Bateson.
Other scientists who were well-known in Cuénot's own day and still into the present day, such as Clarence Little and Sewall Wright
, and William E. Castle
did credit Cuénot with pioneering work in genetics.
For example, Clarence Little and William E. Castle
did credit Cuénot with the discovery of the first lethal mutation.
The mouse geneticist Clarence Little credited Cuénot with the idea and first evidence for multiple allelism, and recognizing that the inheritance of white spotting in the mouse did not breed true.
A note on multiple allelomorphism in Mice. C.C. Little. American Naturalist, 49, 122-125. (1915).
The inheritance of black-eyed white spotting in mice. C.C. Little. American Naturalist, 49, 727-740. (1915).
The mouse and population geneticist Sewall Wright
credited Cuénot with the discovery of multiple alleles and the one-gene one-enzyme hypothesis.
Color inheritance in mammals. II The mouse-better adapted to experimental work than any other mammal-Seven sets of Mendelian Allelomorphs (alleles) identified-Factorial hypothesis framed by
Cuenot on basis of his work with mice. J. Hered. 8,373-378. (1917).
When writing Cuénot's obituary in 1951, Richard Goldschmidt
credits Cuénot with the gene controlling enzyme hypothesis:
"In 1903 he (Cuénot) already understood the genic (genetic) control of pigment in terms of chromogen (genes were responsible for the chromogen) and oxydase (enzyme)."
John Cairns
as recently as 2003 credited Lucien Cuénot with the one-gene one-enzyme hypothesis.
The entry in the 1911 Encyclopædia Britannica, which may be taken as the work of reference for the educated man or woman of that time does fully appreciate Cuénot's work on the relationship between determinants (genes) and ferments (enzymes).
http://1911encyclopedia.org/Albino
“ Before we can inquire into the cause and meaning of albinism it will be necessary first to consider the nature of pigmentation. It has recently been ascertained that the coloration of certain sponges is due to the interaction of an oxydizing ferment (enzymes), tyrosinase, upon certain colourless chromogenic substances. In 1901, Otto v. Furth and Hugo Schneider showed that a tyrosinase could be obtained from the blood of certain insects, and, acting upon a chromogen present in the blood, converted it into a pigmentary substance of melanin-like nature. Hans Przibram also extracted a tyrosinase ' from the ink-sac of Sepia, and, causing it to act upon a watery solution of tyrosin, obtained a black pigment. From the blood of Bombyx mori, V. von Ducceshi has also obtained a tyrosinase.
Subsequently (1903) L. Cuénot, in order to explain certain features in the hereditary transmission of coat colour in mice, postulated the hypothesis that the grey colour of the wild mouse (which is known to be a compound of black, chocolate and yellow pigments) may be due either to the interaction of a single ferment and three chromogens, or vice versa, to one chromogenic substance and three ferments.”
“In spite of the inquiry being only in its initial stages, there is already good evidence to believe that Cuénot's theory is correct, and that an albino is an individual whose skin lacks the power to secrete either the ferment or the chromogen. It forms one but not both of these substances.”
“Not only do albinoes thus carry the determinants (genes) for pattern, but it has been known for some time that they also carry gametically, but never visible somatically, the determinants (genes) for either the ferment (enzyme) or the chromogen (substrate) for one or more colours. L. Cuénot was the first to show this for albino mice.”
Cuénot is in some ways responsible for his lack of acknowledgment. The symbolism he used in experiments described phenotype
rather than genotype
and were quite confusing. (Toda'’s crosses are described in terms of genotype.) His studies on mice were also cut short when German troops invaded the town of Nancy, where he kept his mouse colony. After the war he never returned to his studies on mice and settled for the less controversial subjects of zoology
and physiology
.
Correns
Correns is a commune in the Var department in the Provence-Alpes-Côte d'Azur region in southeastern France.Its name in the Provençal language is Courrens....
, Devries, and Tschermak, Cuénot proved that Mendelism applied to animals as well as plants.
Cuénot's experiments
Cuénot spent two years working on mice and came to the conclusion that three “mnemons” (genes) are responsible for the production of one “chromogen” or pigmentPigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
and two “distases” enzymes. The pigment (if present) is acted upon by the enzymes to produce black or yellow colour. If no pigment is present the result is an albino mouse. Cuénot studied the offspring of various crosses between mice and concluded that these “mnemons” or genes
Gênes
Gênes is the name of a département of the First French Empire in present Italy, named after the city of Genoa. It was formed in 1805, when Napoleon Bonaparte occupied the Republic of Genoa. Its capital was Genoa, and it was divided in the arrondissements of Genoa, Bobbio, Novi Ligure, Tortona and...
were inherited in a Mendelian fashion.
Subsequently, Cuénot was the first person to describe multiple allelism at a genetic locus
Locus (genetics)
In the fields of genetics and genetic computation, a locus is the specific location of a gene or DNA sequence on a chromosome. A variant of the DNA sequence at a given locus is called an allele. The ordered list of loci known for a particular genome is called a genetic map...
.
He also described a lethal mutation
Mutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
in the mouse agouti locus at a time when such a mutation was unheard of.
A voice unheard?
There is some argument over the degree of recognition of Cuénot's pioneering work in his own day, and up until the present.Some scientists who were famous in Cuénot's day such as William Bateson
William Bateson
William Bateson was an English geneticist and a Fellow of St. John's College, Cambridge...
, the man credited the “one gene one enzyme” hypothesis never recognized Cuénot's discovery that certain traits arose due to the presence or absence of an enzyme. Archibald Garrod
Archibald Garrod
Sir Archibald Edward Garrod KCMG, FRS was an English physician who pioneered the field of inborn errors of metabolism.- Education and Personal Life :...
suggested in the early part of the 20th century that certain diseases occurred in the absence of an essential enzyme in a biochemical pathway and that these diseases were inherited as Mendelian recessives. Garrod failed to mention Cuénot in his work. At this time, there was widespread difficulty with reconciling genetics and biochemistry.
Failure of Bateson and Garrod to mention Cuénot's pioneering work on the one gene-one enzyme hypothesis
One gene-one enzyme hypothesis
The one gene-one enzyme hypothesis is the idea that genes act through the production of enzymes, with each gene responsible for producing a single enzyme that in turn affects a single step in a metabolic pathway...
does not take away from the fact that it was pioneering work. Such failure to credit pioneering work would constitute scientific misconduct
Scientific misconduct
Scientific misconduct is the violation of the standard codes of scholarly conduct and ethical behavior in professional scientific research. A Lancet review on Handling of Scientific Misconduct in Scandinavian countries provides the following sample definitions: *Danish definition: "Intention or...
in the present day. That Cuénot's articles were in French may be the reason for Bateson's and Garrod's insular view.
Bateson's failure to mention Cuénot's work may be because Bateson did not like Cuénot. Batson did record in a letter that on meeting Cuénot in December 1905 Cuénot "insisted that the yellow colour of mouse fur was dominant to agouti (grey)" fur colour, and that Bateson found Cuénot "a dull man". There may have been some professional jealousy, as Bateson did receive a letter from Hurst in which he was urged to "read and digest the new Cuénot", work which explained some results in the field of mouse genetics, results which had been confusing for Bateson.
Other scientists who were well-known in Cuénot's own day and still into the present day, such as Clarence Little and Sewall Wright
Sewall Wright
Sewall Green Wright was an American geneticist known for his influential work on evolutionary theory and also for his work on path analysis. With R. A. Fisher and J.B.S. Haldane, he was a founder of theoretical population genetics. He is the discoverer of the inbreeding coefficient and of...
, and William E. Castle
William E. Castle
William Ernest Castle was an early American geneticist.-Early years:William Ernest Castle was born on a farm in Ohio and took an early interest in natural history...
did credit Cuénot with pioneering work in genetics.
For example, Clarence Little and William E. Castle
William E. Castle
William Ernest Castle was an early American geneticist.-Early years:William Ernest Castle was born on a farm in Ohio and took an early interest in natural history...
did credit Cuénot with the discovery of the first lethal mutation.
The mouse geneticist Clarence Little credited Cuénot with the idea and first evidence for multiple allelism, and recognizing that the inheritance of white spotting in the mouse did not breed true.
A note on multiple allelomorphism in Mice. C.C. Little. American Naturalist, 49, 122-125. (1915).
The inheritance of black-eyed white spotting in mice. C.C. Little. American Naturalist, 49, 727-740. (1915).
The mouse and population geneticist Sewall Wright
Sewall Wright
Sewall Green Wright was an American geneticist known for his influential work on evolutionary theory and also for his work on path analysis. With R. A. Fisher and J.B.S. Haldane, he was a founder of theoretical population genetics. He is the discoverer of the inbreeding coefficient and of...
credited Cuénot with the discovery of multiple alleles and the one-gene one-enzyme hypothesis.
Color inheritance in mammals. II The mouse-better adapted to experimental work than any other mammal-Seven sets of Mendelian Allelomorphs (alleles) identified-Factorial hypothesis framed by
Cuenot on basis of his work with mice. J. Hered. 8,373-378. (1917).
When writing Cuénot's obituary in 1951, Richard Goldschmidt
Richard Goldschmidt
Richard Benedict Goldschmidt was a German-born American geneticist. He is considered the first to integrate genetics, development, and evolution. He pioneered understanding of reaction norms, genetic assimilation, dynamical genetics, sex determination, and heterochrony...
credits Cuénot with the gene controlling enzyme hypothesis:
"In 1903 he (Cuénot) already understood the genic (genetic) control of pigment in terms of chromogen (genes were responsible for the chromogen) and oxydase (enzyme)."
John Cairns
John Cairns (biochemist)
John Forster Cairns FRS is a British physician and molecular biologist who made significant contributions to molecular genetics, cancer research, and public health....
as recently as 2003 credited Lucien Cuénot with the one-gene one-enzyme hypothesis.
The entry in the 1911 Encyclopædia Britannica, which may be taken as the work of reference for the educated man or woman of that time does fully appreciate Cuénot's work on the relationship between determinants (genes) and ferments (enzymes).
http://1911encyclopedia.org/Albino
“ Before we can inquire into the cause and meaning of albinism it will be necessary first to consider the nature of pigmentation. It has recently been ascertained that the coloration of certain sponges is due to the interaction of an oxydizing ferment (enzymes), tyrosinase, upon certain colourless chromogenic substances. In 1901, Otto v. Furth and Hugo Schneider showed that a tyrosinase could be obtained from the blood of certain insects, and, acting upon a chromogen present in the blood, converted it into a pigmentary substance of melanin-like nature. Hans Przibram also extracted a tyrosinase ' from the ink-sac of Sepia, and, causing it to act upon a watery solution of tyrosin, obtained a black pigment. From the blood of Bombyx mori, V. von Ducceshi has also obtained a tyrosinase.
Subsequently (1903) L. Cuénot, in order to explain certain features in the hereditary transmission of coat colour in mice, postulated the hypothesis that the grey colour of the wild mouse (which is known to be a compound of black, chocolate and yellow pigments) may be due either to the interaction of a single ferment and three chromogens, or vice versa, to one chromogenic substance and three ferments.”
“In spite of the inquiry being only in its initial stages, there is already good evidence to believe that Cuénot's theory is correct, and that an albino is an individual whose skin lacks the power to secrete either the ferment or the chromogen. It forms one but not both of these substances.”
“Not only do albinoes thus carry the determinants (genes) for pattern, but it has been known for some time that they also carry gametically, but never visible somatically, the determinants (genes) for either the ferment (enzyme) or the chromogen (substrate) for one or more colours. L. Cuénot was the first to show this for albino mice.”
Cuénot is in some ways responsible for his lack of acknowledgment. The symbolism he used in experiments described phenotype
Phenotype
A phenotype is an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior...
rather than genotype
Genotype
The genotype is the genetic makeup of a cell, an organism, or an individual usually with reference to a specific character under consideration...
and were quite confusing. (Toda'’s crosses are described in terms of genotype.) His studies on mice were also cut short when German troops invaded the town of Nancy, where he kept his mouse colony. After the war he never returned to his studies on mice and settled for the less controversial subjects of zoology
Zoology
Zoology |zoölogy]]), is the branch of biology that relates to the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct...
and physiology
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...
.