Key Questions & Quotes on Wild-Type
To What Extent Has There Been Continuity Between Nineteenth and Twentieth century
Conceptions of Wild-Type?
The Problem of Representation: How can Geneticists Justify Extrapolating from
Laboratory Results to Natural Populations?
If Laboratory Wild-Types ‘Stand In For’ Actual Wild Organisms, What do They
Represent? Phenotypes, Genotypes, Epigenotypes?
What is the Relationship Between Wild-Types and Their Environments?
Does Wild-Type have a Place in Molecular Genetics?
What is the Role of Wild-Types in Genetic Practice?
Wild-Type – A Real or Instrumental Category?
Linnaeus: “A variety is a plant changed by an accidental cause: climate, soil, temperature,
winds, etc. A variety consequently reverts to its original condition when the soil is changed”
(Mayr: pp. 640)
Charles Darwin: “The doctrine of the origin of our several domestic races from several
aboriginal stocks, has been carried to an absurd extreme by some authors. They believe that
every race which breeds true… has had its wild prototype. At this rate there must have
existed at least a score of species of wild cattle, as many sheep, and several goats in Europe
alone” (pp. 27); “Now, in every one of the domestic breeds, taking thoroughly well-bred
birds, all of the above marks [of Columbia livia]… sometimes concur perfectly developed.
Moreover, when two birds belonging to two distinct breeds are crossed… the mongrel
offspring are very apt suddenly to acquire these characters… We can understand these facts,
on the well-known principle of reversion to ancestral characters, if all the domestic breeds
have descended from the rock pigeon [alternative suggestions are not parsimonious]” (pp. 33)
Fleeming Jenkin: “A given animal or plant appears to be contained, as it were, within a
sphere of variation; one individual lies near one portion of the surface; another individual, of
the same species, near another part of the surface; the average animal at the centre. Any
individual may produce descendants varying in any direction, but is more likely to produce
descendants varying towards the centre of the sphere, and the variations in that direction will
be greater in amount than the variations towards the surface” (pp. 282)
Alfred Russel Wallace: “Domestic varieties, when turned wild, must return to something near
the type of the original wild stock, or become altogether extinct* [*That is, they will vary,
and the variations which tend to adapt them to the wild state, and therefore approximate them
to wild animals, will be preserved. Those individuals which do not vary sufficiently will
perish]… [N]o inferences as to the permanence of varieties in a state of nature can be
deduced from the observations of those occurring among domestic animals. The two are so
much opposed to each other in every circumstance of their existence, that what applies to the
one is almost sure not to apply to the other. Domestic animals are abnormal, irregular,
artificial” (Contributions to the Theory of Natural Selection, Second Edition, WHS
Corrections and Additions, Macmillan and Co., 1871, pp. 40-41)
Ernst Haeckel: ‘Reversion to the Wild Form’: “When cultivated plants or domestic animals
become wild, when they are withdrawn from the conditions of cultivated life, they experience
changes which appear not only as adaptations to their new mode of life, but partially also as
relapses into the ancient original form out of which the cultivated forms have been
developed. Thus the different kinds of cabbage, which are exceedingly different in form, may
be led back to the original form, by allowing them to grow wild. In like manner, dogs, horses,
heifers, etc., when growing wild, often revert more or less to a long extinct generation. An
immensely long succession of generations may pass away before this power of latent
transmission becomes extinguished.” (The History of Creation: Or the Development of the
Earth and Its Inhabitants by the Action of Natural Causes. A Popular Exposition of the
Doctrine of Evolution in General, And Of That of Darwin, Goethe, and Lamarck in
Particular. Vol. I, E. Ray Lankester (trans.), New York: D. Appleton and Company, 1887.,
pp. 209)
Francis Galton: Galton: “The observed facts of Reversion enable us to prove that the latent
elements must be greatly more varied than those that are personal or patent. The arguments
are as follows:—(1) there must be room for very great variety, because a single strain of
impure blood will reassert itself after more than eight generations; (2) an individual has 256
progenitors in the eighth degree, if there have been no ancestral intermarriages, while under
the ordinary conditions of social and neighbourly life he will certainly have had a
considerable, though a smaller number of them; (3) the gradual waning of the tendency to
reversion as the generations increase conforms to what would occur if each fresh marriage
contributed a competing element for the same place, thus diluting the impure strain until its
relative importance was reduced to an insignificant amount” (pp. 395, ‘On Blood
Relationship’, Proceedings of the Royal Society of London, Vol. 20, 1871-1872, pp. 394-402)
Jean Gayon: “[Galton’s conception of] regression rapidly revealed itself to be a rehabilitation
of the ‘doctrine of the constancy of races’ which had dominated the theory of breeding in the
first half of the 19th century” (Darwinism’s Struggle for Survival: Heredity and the
Hypothesis of Natural Selection, Matthew Cobb (trans.), Cambridge University Press, 1998,
pp. 175)
“It was Mendelism which cut the Gordian knot of selection. By disassociating the operational
notion ‘heredity’ from those of descent and ancestrality, Mendelism forced the science of
heredity away from the contemplation of genealogy and imposed a representation of heredity
as a structure. Furthermore, the extrapolation of Mendelian calculations to the population
level destroyed once and for all the representations of heredity as a force of return... Heredity
could no longer be viewed as... a biological analogy of momentum – it was stripped of any
reference to its effects in terms of ‘force’ or ‘energy’” (Darwinism’s Struggle for Survival:
Heredity and the Hypothesis of Natural Selection, Matthew Cobb (trans.), Cambridge
University Press, 1998, pp. 404)
Bateson: “For the first time Variation and Reversion have a concrete, palpable meaning.
Hitherto they have stood by in all evolutionary debates, convenient genii, ready to perform as
little or as much as might be desired by the conjuror. That vaporous stage of their existence is
over; and we see Variation shaping itself as a definite, physiological event, the addition or
omission of one or more definite elements; and Reversion as that particular addition or
subtraction which brings the total of the elements back to something it had been before in the
history of the race.” (pp. 48, The Methods and Scope of Genetics)
William Castle: “I have shown that the agouti, or wild type of coat of the guinea-pig, results
from the simultaneous presence of three factors, which are separately heritable unit
characters, namely, black pigment, yellow pigment and a factor causing the two pigments to
be disposed in bands. In uniformly colored (or self) varieties of the guinea-pig, at least one of
these three factors is wanting. If the lacking factor is supplied by a cross with a variety which
possesses it, then reversion is obtained, that is a return to the wild type of coat” (pp. 287,
Color Variations of the Rabbit & Other Rodents (1907)); “Knowing the unit-characters borne
by each variety (its gametic formula), one can readily predict the result of crosses between
the several varieties. Any cross which brings together the three factors, B, Y and A, will give
reversion, i. e., a return to the wild type of coat, gray” (pp. 288, Color Variations of the
Rabbit & Other Rodents (1907))
Raphael Falk (see diagram below):
“Unfortunately, Morgan soon realized that extending his notation based on multiple
developmental steps beyond the simple case of two factors acting independently on a
character, actually led to an impossible situation with regard to the use of factors… Morgan
soon realized that it was not only the nomenclature, but also empirical considerations that
required him to abandon efforts to reconcile his embryological top-down conceptions with
Mendelian bottom-up research. It was ‘with much reluctance’ that he suggested a change of
his nomenclature. ‘The change is not one of any theoretical importance, but a practical
necessity for cases of this kind’… He conceded that the name of a new character stands
merely as its symbol… [As Castle however observed] the new nomenclature… was not
‘simply starting the facts’. It was strongly implying exactly what Morgan wished to avoid,
namely a ‘genocentric’ notion of genes being for traits” (Genetic Analysis: A History of
Genetic Thinking, Cambridge University Press, 2009, pp. 233-4)
From: Raphael Falk, Genetic Analysis: A History of Genetic Thinking, Cambridge University
Press, 2009, pp. 232
TH Morgan, Sturtevant, Muller & Bridges:
“In most cases different genetic types produce different results in any ordinary environment.
The environment, being common to the two, may therefore in such cases be ignored, or rather
taken for granted. There are other cases, however, in which a particular genetic type appears
different from another one only in a special environment. Where this environment is not the
normal one, its discovery is an essential element of the experiment” (The Mechanism of
Mendelian Inheritance, 1915, pp. 38)
TH Morgan: “What bearing has the appearance of these new types of Drosophila on the
theory of evolution may be asked. The objection has been raised in fact that in the breeding
work with Drosophila we are dealing with artificial and unnatural conditions. It has been
more than implied that results obtained from the breeding pen, the seed pan, the flower pot
and the milk bottle do not apply to evolution in the "open", nature "at large" or to "wild"
types. To be consistent, this same objection should be extended to the use of the spectroscope
in the study of the evolution of the stars, to the use of the test tube and the balance by the
chemist, of the galvanometer by the physicist. All these are unnatural instruments used to
torture Nature's secrets from her. I venture to think that the real antithesis is not between
unnatural and natural treatment of Nature, but rather between controlled or verifiable data on
the one hand, and unrestrained generalization on the other” (A Critique of the Theory of
Evolution (1916), pp. 84-5)
R.A. Fisher: “The two alternative statements, that the mutant type is generally recessive, or
that the wild type is generally dominant, are formally equivalent; nevertheless, the latter
statement is to be preferred, in view of the behavior of series of multiple allelomorphs, of
which Drosophila furnishes several examples, which have been admirably paralleled in the
albino series in rodents. In these cases it is found that while the wild type is clearly dominant
to the mutant allelomorphs, yet the heterozygote of two mutant allelomorphs is intermediate
between them. The mutant allelomorphs show little or no dominance inter se, although it has
been demonstrated that one can arise as a mutation from another. This group of observations
suggests, therefore, that it is rather a peculiarity of the wild type to be generally dominant
than a peculiarity of the mutant to be recessive to the type from which it arose” (‘The
Possible Modification of the Response of the Wild Type to Recurrent Mutations’, The
American Naturalist, Vol. 62, No. 679, 1928, pp. 115-6)
C.R. Plunkett (from: 1932, 1932, ‘Temperature as a Tool of Research in Phenogenetics:
Methods and Results’, Proceedings of the 6TH International Congress of Genetics, Ithaca 2,
158–169.): “The usual difference . . . between wild-type and mutant characters, in respect to
the effects of temperature, are ascribed, on the basis of this theory, to differences in the
distance of the developmental process from its asymptote at the time it ends: processes
controlled by wild-type genes usually closely approach their asymptotes, while those
modified by mutant genes may be terminated by the effects of other developmental processes
while still very incomplete. This conception is applicable... also to other usual differences
between wild-type and mutant characters, in respect to variability in general and in respect to
dominance, which is merely a special case of interaction of factors affecting the same
phenotypic character. This peculiarity in the physico-chemical kinetics of “wild-type”
developmental processes is a result of natural selection, which tends, in general, to favor a
genotype which produces a relatively uniform phenotype” (In: Falk, Raphael, ‘The rise and
fall of dominance’, Biology and Philosophy, Vol. 16, pp. 285-323, 2001, pp. 310)
Theodosius Dobzhansky
“The ability of the gene complexes carried in second chromosomes of wild Drosophila
pseudoobscura to produce, through recombination, a great variety of new gene complexes
disrupts the notion of ‘normal’ or ‘wild type’ chromosome, genotype, or phenotype. In
general, these notions only exist because of the reluctance of the human mind to abandon the
idea of a finite number of static prototypes underlying the unmanageable… multiformity of
the living nature… it is, nevertheless, [in non-polymorphic species] convenient for
descriptive purposes to contrast mutant or aberrant individuals or strains with normal or wild
type ones” (‘Genetics of natural populations. XIII. Recombination and variability in
populations of Drosophila pseudoobscura’, 1945)
A. R. Cordeiro and Theodosius Dobzhansky:
“Except in polymorphic species, individuals which occur in natural populations of most
organisms are sufficiently uniform in phenotype to be described simply as "normal," or
representing the "wild-type" of their respective species or races. It is legitimate to use the
concept of "norm" to facilitate the description of mutants and of genetical and
environmentally induced aberrations that occur from time to time. Unfortunately, some
biologists have gone beyond this, and came to regard the "norm" as a sort of ideal prototype
of which the actually existing individuals are imperfect copies. This typological thinking, the
roots of which go down to the Platonic philosophy, is basically anti-evolutionistic, and has
produced much confusion in biological though” (‘Combining Ability of Certain
Chromosomes in Drosophila Willistoni and Invalidation of the "Wild-Type" Concept’, The
American Naturalist, Vol. 88, No. 839, 1954, pp. 83)
Rachel Ankeny:
“For C elegans, the wild type worm is from a certain strain (Bristol) and has been genetically
purebred since its adoption by Brenner in the 1960s; however, the selection of this variant as
the wild type was relatively arbitrary and dependent not on its typicality (e.g., later use of the
Bergerac strain allowed detection of transposons; see Anderson et al. 1992) as much as on the
ease of its experimental manipulability” (‘Fashioning Descriptive Models in Biology: Of
Worms and Wiring Diagrams’, Philosophy of Science, Vol. 67, Supplement. Proceedings of
the 1998 Biennial Meetingsof the Philosophy of Science Association. Part II: Symposia
Papers (Sep., 2000 pp. S265)
“[T]he first step in the underlying strategy [of classical genetics] is to select and establish a
“wild type” for the organism (taken as a standard from among other possible wild types
available in nature) against which other genetic variants or abnormal types can be compared.
Despite its name, the wild type may not be the most common, frequent, or even a “normal”
version of the organism; sometimes it is simply the first strain that was discovered on which
subsequent research has been based, but is oftentimes the easiest to manipulate
experimentally. These experimental organisms of course are “natural”, inasmuch as they are
still actual, living, concrete organisms, and have been “selected from nature’s very own
workshop”. However, the carefully selected wild type is, in this sense, an idealized model of
actual organisms in nature, since oftentimes they end up differing considerably from those
highly rarefied beasts that remain isolated in the laboratory, particularly as a model organism
comes to be more widely used. Thus modelling occurs in most obviously in the establishment
of the wild type, which is an essential first step to establishing and using something on an
ongoing basis as a model organism. Without this, it is not possible to have a “norm” against
which “abnormal” (or more precisely, that which is variant) can be compared, in terms of
genetics, developmental lineages, and so on” (‘Wormy Logic’, 2006, pp. 8)