The genetical theory of race, and
anthropological method*

by Ashley Montagu

Although there seems to be a great difference between widely separate nations, that you might easily take the inhabitants of the Cape of Good Hope, the Greenlanders, and the Circessians for so many different species of men, yet when the matter is thoroughly considered, you see that all do so run into one another, and that one variety of mankind does so sensibly pass into the other, that you cannot mark out the limits between them.

Very arbitrary indeed both in number and definition have been the varieties of mankind accepted by eminent men.

Thus wrote Johann Friedrich Blumenbach (1752-1840) in the year 1775 in his De Generis Humani Varietate Nativa (Goettingen), a work completed and published when the author was but twenty-three years of age, and one which is quite rightly regarded as marking the birth of what may at some time become the science of physical anthropology.

In the greatly enlarged and revised third edition of this work, published in 1795, Blumenbach concluded that “No variety of mankind exists, whether of colour, countenance, or stature, etc., so singular as not to be connected with others of the same kind by such an imperceptible transition, that it is very clear they are all related, or only differ from each other in degree.”

Not only did Blumenbach make clear the essential unity of mankind, but he also clearly recognized and unequivocally stated the fact that all classifications of the so-called varieties of mankind are arbitrary. “Still,” remarked Blumenbach, “it will be found serviceable to the memory to have constituted certain classes into which the men of our planet may be divided.”1

The history * Based on a paper read at the Annual Meeting of the American Association of Physical Anthropologists, New York, 15 April, 1940. 1. J. F. Blumenbach, On The Natural Variety of Mankind. Translated and edited by Thomas Bendyshe in The Anthropological Treatises of Johann Friedrich Blumenbach (London, 1865), pp. 99 et seq. of physical anthropology, after the death of Blumenbach in 1840, may be described in terms of the gradual inversion of this genetic approach to the problem of the variety of mankind. The investigation of causes steadily gave way to the description of effects, as if the classification of mankind into as distinctive groups as possible were the proper function of a science of physical anthropology. The Darwinian conception of evolution as dealing with continuous materials which, without selection, would remain unchanged, led anthropologists to believe that taxonomic exercises in the classification of mankind, both living and extinct, would eventually succeed in elucidating the relationships of the various groups of mankind to one another. We now know, however, that the materials of evolution are not continuous, but discontinuous, and that these materials are particulate, independent genes, which are inherently variable and unstable. Thus, classifications based on morphological characters and physique can be extremely misleading.2 2. For a brilliant discussion of this subject see Lancelot Hogben’s The Concept of Race in his Genetic Principles in Medicine and Social Science (New York, 1932), pp. 122-144. 3. W. H. Thorpe, Biological Races in Hyponemeuta padella L. (Journal of the Linnaean Society (Zoology), Vol. 36, 1928), p. 621. Biological Races in Insects and Allied Groups (Biological Reviews, Vol. 5, 1930), p. 177. Ecology and the Fulure of Systematus in The New Systematics (Edited by Julian Huxley. Oxford: At The Clarendon Press, 1940), p. 58. How misleading may be gathered from the fact that in Nature there actually exist many groups of individuals in different phyla which are distinct species in every sense but the morphological one.3 The converse is also true, that is, individuals of the same species may exhibit morphological differences which the taxonomist would be led to assign to different specific rank. Such classificatory efforts belong to the pre-Mendelian era. Then, as now, the concept of the continuity of species and the existence of transitional forms was associated with a belief in missing links. The anthropologist conceived his task to be the discovery of these links so that when they were all joined together we should have a perfectly Great Chain of Being leading from the most “primitive” to the most “advanced” form of man. In this manner was established a “racial” anthropology which sought to identify some of these links among existing peoples upon the basis of the physical differences which averaged groups of them exhibited.

For the past hundred years anthropologists have been directing their attention chiefly towards the task of establishing criteria by whose means “races” of mankind might be defined. All have taken completely for granted the one thing which they were attempting to prove, namely, the existence of human “races.” What a “race” is no one exactly seems to know, but everyone is most anxious to tell. What a “race” is no one exactly seems to know, but everyone is most anxious to tell. The customary anthropological practice of describing the end-effects of complex variations, without in the least attempting to consider the nature of the conditions responsible for those end-effects, can never lead to any understanding of their real meaning. In order to understand the end-effects with which the physical anthropologist has been so much concerned it is necessary to investigate the causes producing those end-effects, and this can only be done by studying the conditions under which they come into being, for it should be obvious that it is the conditions which produce the end-effects which must be regarded as the efficient causes of them.

Comparing numerous series of metrical and non-metrical characters relating to different varieties of man may provide us with some notion of their likenesses and differences, and tell us something of the variability of some of their characters, and this is necessary and important, but no amount of refined description and comparison will ever tell us how such groups came to be as we now find them, unless a serious attempt be made to discover the causes operative in producing them.

Such causes are at work before our eyes at the present day. In this country and in many other parts of the world where different “racial” groups have met, determinate sequences, if not the actual mechanism, of “racial” change may be studied. The discoveries of geneticists concerning the manner in which genetic changes are produced in other organisms, and what little is known of human genetics, renders it perfectly clear that the genetic systems of all living things behave fundamentally according to the same or similar laws. If this is true, it then becomes possible, for the first time in the history of man, to envisage the possibility of an evaluation in genetical terms of the past stages through which man, as a variable species, must have passed in order to attain his present variety of form, and also, in the same terms, to account for that variety.

The full discussion of the principles of the genetic approach to the study of the evolution of the variety of mankind cannot be attempted here; all that can be done is to present a condensed statement of the genetical theory of “race.”

The conception of “race” here proposed is based upon the following fundamental postulates:

  1. That the original ancestral human species population was genetically relatively homogeneous.4 4. It does not, in fact, much matter whether we begin with a relatively homogeneous or a very much mixed or diversified population, or series of populations. Whichever alternative we adopt, the results, and the processes involved, are essentially the same.
  2. That, by migration away from this original ancestral group or population, individual families, or groups of families, became dispersed through space.
  3. That some of the groups thus dispersed became geographically isolated from one another, and remained so isolated over more or less considerable periods of time.
  4. That upon all of these isolated groups several of the following factors came into play as conditions leading to evolutionary change:
    1. The inherent variability of the genetic materials composing each individual member of the group.
    2. Physical change in the action of a gene associated, in a partial manner, with a particular character, that is, gene mutation.

Inherent variability describes the fact that given a genetically homogeneous, or homozygous, group, random variations in gene frequencies will, with the passage of varying intervals of time occur so that such groups will, in time, come to exhibit certain differences from other isolate groups, or ecotypes, which started with the same genetic equipment.

Mutation defines the condition in which a particular gene undergoes a permanent change of some sort, and whose action expresses itself in the appearance of a new form of an old character. Mutations have almost certainly occurred independently in different human isolate groups, at different times and at different rates, and have affected different characters. Thus, for example, in one part of a population, or ecotype, mutant homozygous genes leading to the development of kinky hair may have appeared and ultimately become scattered throughout the population, as among Negroes. If we may assume that “black” was the primitive skin color of man,5 5. There is equally good reason to believe that the primitive skin color of man was “white.” Among living chimpanzees, for example, one finds completely “white” and completely “black” skins. Whatever skin color we commence with in man the genetic processes involved in producing his present variety of skin color are the same. then in another population mutant genes resulting in a brownish skin color may have appeared, while still another population may have mutated in the direction of a yellowish skin, and finally by subsequent mutation white skin may, indeed upon this hypothesis must, in this way have made its appearance.

Up to this point we have seen that it is possible to start with a genetically relatively homogeneous population from which independent groups have migrated and become isolated from one another, and that by random variation in gene frequencies and the change in the action of genes themselves—omitting for the moment the operation of factors such as selection of various sorts—new genetic combinations of characters have appeared which, in so far as they differ from those which have appeared in other groups, define the differences existing between such groups. In brief, random variation and the action of mutant genes are the primary agencies responsible for the production of physical differences between human groups. In fact, these constitute the basic processes in the evolution of all animal forms. But there are other factors involved which, though secondary in the sense that they act upon the primary factors and influence their operation, are not less important in their effects than the primary factors. Indeed, these secondary factors, ecological, natural, sexual and social selection, inbreeding, outbreeding and so on, have been unremitting in their action upon the primary factors, but the character of that action has been very variable. The action of these secondary factors does not require any discussion here. I wish here to emphasize principally that in the character of the action of the two primary factors, gene variability and gene mutation, we have the clear demonstration that the variability of all human groups is a natural process which is constantly proceeding. And it is here being suggested that “race” is merely an expression of the process of genetic change within a definite ecologic area; that “race” is a dynamic, not a static, condition, and that it becomes static and classifiable only when a taxonomically minded anthropologist arbitrarily delimits the process of change at his own time level.

Given a sufficient amount of time all genes mutate. The frequency with which various genes have undergone change or mutated in human groups is at present unknown, but when, as anthropologists, we shall have addressed ourselves to the task of solving the problem of gene variability in different human groups, important discoveries may be expected. The immediate task of the physical anthropologist interested in the origins of human variety, is to investigate the problem presented by that variety not as a taxonomist but as a geneticist, since the variety which is loosely called “race” is a process which can only be accurately described in terms of the frequencies with which individual genes occur in groups which represent adequate ecologic isolates.

If “race” and “racial” variability can best be described in terms of gene frequencies, then among the most important of our tasks must be that of discovering what roles the primary and secondary factors play in producing that variability.

The approach to the solution of this problem is twofold. First, through the analysis of the character of the variability itself in definitely localized groups, and second, through the study of the effects of “race” mixture among living peoples. Such studies as those of Fischer, Herskovits, and Davenport and Steggerda, have already shown what can be achieved by means of the genetic approach.6 6. E. Fischer, Die Rehobother Bastards und das Bastardierungsproblem beim Menschen (Jena, 1913); M. J. Herskovits, The American Negro (New York, 1928); The Anthropometry of the American Negro (New York, 1930); C. 33. Davenport and M. Steggerda, Race Crossing in Jamaica (Carnegie Institution of Washington, 1929). 7. T. Dobzhansky, Genetics and the Origin of Species (New York, 1937), p. 62. As Dobzhansky has pointed out,

The fundamental units of racial variability are populations and genes, not the complexes of characters which connote in the popular mind a racial distinction.7

It is with such complexes that physical anthropologists have been for so long fruitlessly dealing. As Dobhansky writes, the error of the pre-Mendelians lay in the fact that “they treated as units the complexes of characteristics of individuals, races, and species, and attempted to find rules governing the inheritance of such complexes. Mendel was the first to understand that it was the inheritance of separate traits, and not of complexes of traits, which had to be studied. Some of the modern students of racial variability consistently repeat the mistakes of Mendel’s predecessor.”8 8. Ibid.

In man the process of “race” formation is genetically best understood in terms of the frequency with which certain genes become differentiated in different groups derived from an originally relatively homogeneous species population and subsequently undergo independent development. We have already seen that the mechanisms involved in differentiating a single collective genotype into several separate genotypes, and the subsequent development of a variety of phenotypes within these genotypes, are primarily gene variability and gene mutation, and secondarily, the action of such factors as environment, natural, social, and sexual selection, inbreeding, outbreeding and the like.

The physical differences existing between the living races of man probably originally represent the end effects of small gene mutations fitting harmoniously into gene systems which remain relatively unaltered. The number of genes involved is very small, at the maximum, probably no more than one per cent, each being for the most part independent in its action.

Quite as important as the primary factors in the production of the genetic variety of mankind are the secondary factors, such as migration, social and sexual selection, endogamy, exogamy, and the like. These processes are akin to those practised in the production of domestic breeds of animals from wild types, in which generic, specific, and racial characters which, under natural conditions, in the secular period of time concerned, would have remained stable, are rendered markedly unstable, as in our artificially produced varieties of cats, dogs, horses, and other domesticated animals.

The common definition of “race” is based upon an arbitrary and superficial selection of external characters. At its very best it may in genetic terms be redefined as a group of individuals an appreciable majority of whom, taken at a particular time level, are characterized by the possession of a certain number of genes which are phenotypically, that is, on the basis of external characters, arbitrarily selected as marking “racial” boundaries between them and other groups of individuals of the same species population not characterized by so high a degree of frequency of these particular genes.

This is perhaps granting the common conception of “race” too much credit for either significance or intelligibility, but it should be obvious that such a definition represents a rather fatuous kind of abstraction, a form of extrapolation for which there can be little place in scientific thought. What, for instance, does “an appreciable majority” refer to? What are the characters which are to be exhibited by this “appreciable majority?” And upon what grounds are such characters to be considered as significantly defining a “race?” As Dobzhansky points out, “The geographical distributions of the separate genes composing a racial difference are very frequently independent.”9 9. Dobzhansky, op. cit., p. 77. Thus, blood group distributions are independent of skin color, or cephalic index distributions, and so on. What aggregation then, of gene likenesses and differences constitutes a “race” or ethnic group? The answer to this question awaits further research. Meanwhile we may venture a definition of an ethnic group here.

An ethnic group represents part of a species population in process of undergoing genetic differentiation; it is a group of individuals capable of hybridizing and intergrading with other such ethnic groups, to produce further genetic recombination and differentiation.

In an expanded form this definition may be written as follows:

An ethnic group represents one of a number of populations comprising the single species Homo sapiens, which individually maintain their differences, physical and cultural, by means of isolating mechanisms such as geographic and social barriers. These differences will vary as the power of the geographic and social barriers, acting upon the original genetic differences, vary. Where these barriers are of low power neighboring groups will inter-grade, or hybridize, with one another. Where these barriers are of high power such ethnic groups will tend to remain distinct or replace each other geographically or ecologically.

An example will make this definition clear. When American Negroes marry and have a family, their children more closely resemble other American Negroes, as well as Negroes elsewhere in the world, than they do American or other whites. This merely means that the offspring have drawn their genes from a local group in the population in which certain genes, say for skin color, were present which were not present in other local groups of the American population. Now, the manner in which such genes are distributed through a population such as ours is determined not so much by biological factors as by social ones. This may be illustrated by means of a homely example. If Negroes were freely permitted to marry whites, the physical differences between Negroes and whites would eventually be completely eliminated through the more or less equal scattering of their genes through the population. That this has not occurred to any large extent is due principally to the erection of social barriers against such “miscegenation.” Such social barriers tend to keep the stocks with white and Negro genes separate. In this manner such barriers act as isolating factors akin to natural geographic isolating factors, which have the same effect in maintaining the homogeneity of genetic characters within the isolated group.

It will be seen that such a definition emphasizes the fact that so-called “racial” differences simply represent expressions of variations in the relative frequencies of genes in different parts of the species population, and rejects altogether the all-or-none conception of “race” as a static, immutable process of fixed differences. It denies the unwarranted assumption that there exist any hard and fast genetic boundaries between any groups of mankind, and asserts their essential common genetic unity. Such a conception of “race,” cuts across all national, linguistic, religious and cultural boundaries and thus asserts their essential independence of genetic factors.

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