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Exceeding Hrdlička's aims: 100 Years of genetics in anthropology

2018; Wiley; Volume: 165; Issue: 4 Linguagem: Inglês

10.1002/ajpa.23406

1096-8644

Emőke J. E. Szathmáry,

Race, Genetics, and Society

What role has genetics played within physical anthropology? My answer is colored by my perceptions of the discipline, linked to my decision to embrace it. For example, I chose to pursue human population genetics in an anthropological context because I believed that genetic approaches would be more likely to yield secure answers to questions that intrigued me, than would the methods of skeletal biology. I had great faith in answers that genetics could provide about the human species, and how its members came to be globally distributed. Fifty years after I entered graduate school I know we have learned much about evolution and humanity by combining genetics and anthropology, but my pleasure in that knowledge is dampened by my awareness that to many outside our discipline, genes determine everything. Too many regard the content of their genes as defining who they are. Television advertising, for example, features happy individuals who claim to have had their genetic ancestry determined, for example, "I thought I was German but I am really Scottish." Advertising is designed to sell a product, as it sends the message that genes provide the facts about the essence of an individual and the groups to which one belongs. That notion sounds much like ideas at the American Journal of Physical Anthropology's (AJPA) beginning. What have physical anthropologists learned in the interim? "The farther back we go in time, the less important becomes the store of scientific knowledge of the period and the more important the general intellectual atmosphere" (Mayr, 1982, p. 14) In the first issue of the AJPA Aleš Hrdlička defined Physical Anthropology as "the study of man's variation" (Hrdlička, 1918a, p. 4). His exposition of the nature, the scope and the aims of this discipline also surveyed what had been accomplished by physical anthropologists and allied scientists, and listed their publications (Hrdlička, 1918a, 1918b, c, d). Hrdlička's scientific goals for our discipline were grounded in three assumptions: (1) the objects of investigation would be morphological, representing present, past, and ancient (fossil) members of humanity, as well as nonhuman primates; (2) human variation is categorical, and is manifest as "races"; and (3) physical anthropology is both a scientific and applied discipline, and the applications should serve the betterment of humanity. With respect to scientific aims, the data collected would elucidate human phylogeny, including the evolutionary changes that had occurred over time. The data would also allow learning everything that could be learned about the "White race", though other "races" could serve as well in exploring the biology of humanity, except that little skeletal material was available on these groups. Hrdlička believed that American physical anthropologists in particular, should focus on: (1) indigenous Americans, including "Eskimos," not only to determine the range of variation manifest in this "race," but also to determine their origin and antiquity in the Americas; (2) the developments of African-Americans, and (3) determine "the results of admixture of whites with the negro and the Indian" (Hrdlička, 1918a, p. 22). Hrdlička appears not to have expected much from genetics in addressing issues relevant to physical anthropology. He never used the term "genetics" in this major essay, for example, though the word and its meaning were coined in 1905 by William Bateson (Gayon, 2016, p. 226). Shultz (1944) observed that Hrdlička had little interest in genetics, likely because he had only an elementary command of mathematics, and little background in biology. These deficiencies also explain his avoidance of statistics (Ortner, 2010). At the same time, he was aware of genetics, and had appointed a human geneticist, Charles B. Davenport, as one of the charter Associate Editors of the AJPA, whose duties included reporting regularly on research in human genetics that was published in other periodicals (Ortner, 2010: see Fig 4.3). Hrdlička's terminology also contained concepts familiar to geneticists, and he observed that physical anthropologists had "participated in and promoted studies in human heredity, degeneration, and hybridity" (1918a, p. 12). Why did Hrdliĉka regard "admixture," "degeneration," and "hybridity" as important? The method for computing a gene-based method for calculation of the magnitude of admixture had not yet been formulated (Beerli, 2016). In fact, Hrdlička was concerned about admixture and "degeneration" because of the claimed potential "physical, physiological, and intellectual effects" of racial mixtures (Hrdlička, 1918a, p. 20), not only between what have been called, geographic races (Garn, 1971), but also between established Americans and recent immigrants to the United States, primarily from southern and eastern Europe. Though Hrdlička was not a eugenicist (Ortner, 2010), he predicted that "eugenics will essentially become applied Anthropology" (1918a, p. 21). At the same time he placed physical anthropology's primary aims first, and said that efforts directed towards eugenics "must remain more or less empirical and impotent" (1918, p. 22). Several authors have argued that Hrdlička's concern about race and eugenics in the inaugural issue of the AJPA was partly a consequence of the political circumstances under which the AJPA was founded. Hrdlička had to keep the support of powerful individuals, regardless that they were racists and eugenicists (Caspari, 2009; Marks, 2012; Spiro, 2009). Barkan (1992, p. 99) took a more psychological interpretation of Hrdlička's behaviour: "Hrdlička displayed the ambivalence of an immigrant outsider, who tried to be accepted by the establishment, and in an effort to gain respectability adopted much of its bigotry, although for scientific as well as more personal reasons he was inclined to refute racism on scientific grounds rather than for ethnic reasons." Nevertheless, before the inaugural issue was launched Hrdlička broke connections with the wealthy patrician, Madison Grant, who led the eugenics group, and he appointed Franz Boas, Alfred Kroeber, and Henry K Donaldson as Associate Editors. Spiro has concluded that Hrdlička's actions ensured that the AJPA "never became a mouthpiece for the hereditarians" (Spiro, 2009, p. 321). Underlying that fact, whether intended or not, the AJPA's focus on human "racial" variation permitted an accumulation of articles that challenged assumptions about the race concept, simply because the findings did not fit the expectations. Eventually, someone noticed that this meant there were no races (Livingstone, 1962). However, in 1918, most scientists, and the broader society in which the scientific community was embedded, had different ideas than prevail today. An unresolved question in 1918 was the concept of "race," not just biologically but behaviorally. It was an issue in Britain and Scandinavia, but according to Kevles (1999), was not nearly as enormous an issue as it was in the United States and Canada. Several inter-related beliefs were then pervasive in North American societies: (1) Whites [i.e., "Aryans" (Henshaw, 1889); "Nordics" (Kyllingstad, 2012; Spiro, 2009)] were placed at the top of a ranked hierarchy of peoples defined by biological traits; (2) mental traits and cultural accomplishments were linked with biological traits and believed to be inherited together; and (3) many believed that biological change from one generation to the next should be undertaken with the methods of eugenics (Caspari, this issue; Kevles, 1985; Ortner, 2010; Spiro, 2009). Within the scientific community these ideas were linked to notions about the origin of humanity. For example, Samuel G. Morton, who had been dead almost 70 years at the time of the founding of the AJPA, and whom Hrdlička regarded as the "father" of American physical anthropology (Hrdlička, 1918a), believed that races were separate species, and that after admixture of Blacks and Whites, "fixed traits" emerged in the offspring in spite of the blending of features such as skin color. August Wiseman's demonstration in the 1880s that acquired traits could not be inherited, and that hereditary information was transmitted by the germ plasm (gametes) (Zou, 2015) led to an even stronger conviction among physical anthropologists of the early 20th century that fixed traits existed (Kaplan, 1954, p. 781). After 1900 the increasing prominence of Mendelism—the manner in which hereditary traits were transmitted from parents to offspring—just increased the belief that heredity was more important than environment in determining human characteristics (Kevles, 1985). In such an intellectual milieu the methods by which fixed traits could be identified was important. The rediscovery of Gregor Mendel's research highlighted the breeding experiments that agricultural scientists had been conducting for decades. By crossing closely related animals, or plants, and by examining offspring over several generations of cross breeding, agricultural scientist identified heritable variations, or new traits that might further evolve (Kevles, 1985). Admixture between human "races" could therefore serve as "natural experiments" which yielded offspring that could be examined to find the "fixed traits" that defined each "race." In addition, studies of the offspring of admixture could serve at least two other purposes. Eugenicists like Charles B. Davenport, a human geneticist and Associate Editor of the AJPA, were keen on finding evidence that miscegenation led to a "degeneration" of the "White race" (Spiro, 2009). In contrast, anthropologists like Franz Boas and Alfred Kroeber, also Associate Editors of the AJPA, represented a vanguard of anthropologists who were increasingly challenging ideas about "race" (Caspari, 2009). Boas' (1894) research on mixed-blood Sioux women, for example, did not support the notion that they were less fertile than so called "pure races", contrary to predictions arising from polygenism. Boas advocated for studies "to investigate the truth or fallacy" (Boas, 1909, p. 846) of theories about the consequences of admixture, including "degeneration" of racial type, and "the superiority of the blond race," which he certainly doubted (Boas, 1919, p. 363). His findings on skeletal plasticity (Gravlee, Bernard, & Leonard, 2003; LeVine, 2010) challenged the belief that "fixed traits" existed. In the context of 1918 then, it is not surprising that Hrdlička regarded particular kinds of investigations as especially important to physical anthropologists. "Hybridity" and its consequences were as important to polygenists as "admixture" was to eugenicists like Davenport, and to Darwinian monogenists like Boas and Hrdlička, who above all believed that evidence was required to determine what was true about "race" (Anderson, 2012). "problem was that aside from self-interested rhetoric, genetic research did not seem to have anything to add to the corpus of physical anthropology that was either not obviously false or manifestly useless aside from documenting additional differences among human populations. If there was a lack of enthusiasm within physical anthropology for genetics, it was not for lack of interest: the meaning of the work for understanding what physical anthropologists were primarily interested in was very unclear" (2012:S164). When we compare past knowledge with what we know today, it is easy to judge negatively. Regardless, is Marks' harsh appraisal justified? A bifurcating answer of either "no" or "yes" does not do justice to the matter. Marks's summary uses the words "genetic research", not in the broad sense of inheritance of particular traits, for example, eye color, albinism, or dermatoglyphics, among others, but narrowly, meaning serology only. His essay was undertaken to correct what he believes were flawed assessments and omissions in accounts of the origin of anthropological genetics, among them by William Pollitzer (1981) and by Michael Crawford (2007). That Marks chose to focus attention on work in human serology and systematic serology is at first glance laudable. However, his commentary contradicts Cavalli-Sforza's, who has regarded the studies of the blood group systems, beginning with the ABO system, as "foundational" to "anthropological genetics" and to studies in "human genome diversity." Marks tends "to view the ABO blood group work as marginal in several ways: as scientifically suspect, as negative in its influence, as outdated, and even as racist (Gannett & Griesemer, 2004, p. 119). Studies on the ABO blood group system were published in a very wide array of journals, not just the AJPA. The ABO blood groups were prominent because they were discovered in 1900, long before the MN system was found (1927), and the Rh blood groups were identified in humans (1940) not just in rhesus macaques (Race & Sanger, 1968). The AJPA first published an article that included MN blood group distributions in 1937 (Boyd & Boyd), and in 1944 for Rh blood groups (Wiener, Belkin, & Sonn, 1944). Is it possible to resolve the differences between two radically different perspectives on the value of the pre-World War II research in human serology? Gannett and Giesner's (2004) examination of the dispute is worth reading because as philosophers of science, they are disinterested parties. To them, the differences in the interpretation of the value of ABO blood group studies Illustrates "methodological and conceptual issues" relevant to the study of human genome diversity, and as such, they believed them to be too important to be disregarded as "disciplinary maneuverings" (Gannet & Griesemer, 2004, p. 119). Though disciplinary rhetoric on both sides entered into the dispute, central to it was classification—subjective classification (a priori) was regarded as "racial," whilst objective categorization (a posteriori) was claimed to be unbiased. Gannett and Griesemer's analytic approach to the geography of ABO blood group distributions showed that "objectivity with judgment" is required to map ABO distributions, that is, circularity does indeed enter into classification. However, they did not agree with the use of this fact by critics of genetic anthropology to fuel disciplinary rhetoric, or to judge matters according to "epistemic virtue"—that is, the intellectual values and vices of disciplinary protagonists. Having shown that the old ABO classifications of humanity by geographic area are defensible, they argued for a need to move forward from the old dichotomies (e.g., objective/subjective; good/bad), and develop a "conception of science appropriate to our time and place" (Gannett & Griesmer, 2004, p. 168). Where do I stand on the value of the early blood group studies, especially as presented in the AJPA? Marks' assessment of human serological research before World War II rests on more than his issues with Cavalli-Sforza, thus it is wiser first, to examine briefly what had been published. Almost all of the articles dealing with blood group distributions were not undertaken by anthropologists. This is certainly true of the papers published in AJPA as well. An excellent summary of the state of knowledge about biological inheritance, within which serological research progressed (1901–1918) has been provided by Weiss and Chakraborty (1982). They also detailed the conflicting views that arose after 1919, when Ludwik and Hanna Hirszfeld (aka Hirschfeld using the German spelling; Allan, 1963) discovered that ABO blood type frequencies differed among soldiers of different armies at the Macedonian front. The question centered on how one could account for the variation in blood types shown around the globe: were they caused by single mutational events, and the timing of population expansions in the past determined what ABO genes were carried by subsequent migrations, or were there recurrent mutations, specific to each "race," which also spread around the world and mixed with others to produce the variation seen today. As late as 1940 the views were still in conflict, though the "recurrent mutation" idea lost ground by 1942 (Weiss & Chakraborty, 1982). It took over 20 years for views to change, during which arguments reigned among geneticists, and the physicians just published more and more descriptive blood group studies. Reading the old papers, however, is useful in other ways than just showing the evidence accumulated in favor (or not) of an evolutionary theory. If one can read past the frank errors relative to what is known today, and other flaws in substance and style, the old articles remain instructive because they indicate the influence of new technology applied to old ways of thinking, and how researchers grappled with applying new tools to newly arising issues that they now had the means to address. These actions also need to be known, because they have parallels in our own times. I have selected a few articles by decade, to illustrate these points. LH Snyder, a respected human geneticist, wrote about the inheritance and the "racial" significance of the ABO blood groups when there was no agreement on nomenclature, and the inheritance pattern of the ABO blood groups suggested by Felix Bernstein, was awaiting confirmation by family studies. Three years later, whether or not the ABO genes were allelic, and what their transmission pattern was, were still argued by Tanemoto Furuhata (1929), whose nomenclature ("ABO") won out over Bernstein's "ABR" though not his "nonallelic" model of inheritance (Yoshida, 1982). Regardless of the ambiguity of inheritance pattern of the ABO system at the time of his writing, Snyder recognized the significance of the ABO blood groups for racial classification. He used the term "race" in different ways: for the species H. sapiens ("human race" – p. 236), for geographic "races" (e.g., "American Indians" – p. 235), and he explicitly chose to use the terms "nationalities" or "peoples" rather than "races" as was common then, for the 50 groups tested by others, which he compiled in tables (1926, p. 235). He thought the "biochemical index" (also called the "racial index") used to distinguish "races" on the basis of the ratios of their A, B, and AB blood types was useless. Because it was then believed that there had been "pure races", the appearance of genes A and B of the ABO system suggested to some that humanity had two separate origins, a "race" with A and a "race" with B—but Snyder dismissed the notion. Polygenesis was not necessary; mutation could have produced the ABO variants in a single population. From that single group migrations occurred, and Snyder believed the timing of those expansions could be reflected by living groups that lacked the A and B alleles (e.g., some Native Americans), or had them, because their ancestors undertook migration later, after the variant alleles had appeared. His studies on Cherokee people suggested to him that ABO blood group frequencies were stable over time, were not affected by natural selection, and reflected accurately admixture with other populations that had taken place in the past. Snyder did think that geographic "races" could have evolved genetically under differing environmental influences after populations expanded from the original source. He also mapped peoples around the globe on the basis of their ABO gene frequencies, noting that where he put the boundaries geographically was purely arbitrary, "merely for the sake of convenience in dealing with the data. The first necessary step in considering the blood group data is to arrange it in some sort of logical order" (Snyder, 1926, p. 244). In sum, Snyder's ideas influenced a lot of people that, blood groups were important to those who were interested in human heredity, origins and the evolutionary process. They were also useful to those whose core interest lay in "races," but in ways different than they expected. The cultural anthropologist, AL Kroeber, following a suggestion by JBS Haldane, plotted gene frequencies and their ratios to see if the clusters formed would fit known "racial" classifications based on anthropometry—and found among other things that, agreement occurred in some cases, and not in others (Kroeber, 1934). A year earlier, albeit in another journal than the AJPA, WW Howells had published a study of anthropometric measurements and ABO blood types of indigenous peoples of Fiji and the Solomon Islands. There were some problems, leading Howells to observe that, "Statistics are like fire, excellent servants, but dangerous masters. No conclusive evidence of linkage between a blood group or factor and any somatological characteristic has yet been brought forth" (Howells, 1933, p. 327). In fact, the blood groups provided "meager" assistance in ferreting out answers about the claimed origins of the Fijians, whom Howells thought exhibited a "strongly Polynesian nature" (1933, p. 335). For him, a more intensive anthropometric study linked with craniometric examination of museum collections was in order. Howell's study remains an example of a holistic approach, informed by ethnological and archaeological knowledge, in contrast to articles typically penned by serologists who focussed only on "the science." Candela (1936) published the first of many articles in the AJPA that dealt with identifying blood groups in ancient bone. Candela's initial foray was prompted by Boyd and Boyd's success two years earlier, in blood typing skeletal tissue from Egyptian mummies estimated to be about 3,500 years old. Candela corroborated their findings, which showed the majority of ancient Egyptians to have been blood type B. He also noted that the laboratory methods he employed would be useful not only for blood group determination of ancient Egyptians, but also to trace the changes that have occurred in the blood groups in this population as a consequence of conquest and invasion. Some studies included tests to see if genotype proportions conformed to theoretical expectations. Boyd and Boyd (1941), for example, not only noted the confusion between the meaning of endogamy and inbreeding, but they also sought to detect inbreeding effects in a sample of Syrian villagers from a community in which marriages among cousins and other consanguineous relatives were known. They were unable to show either an increase in homozygotes (MN system) or a decrease of heterozygotes (ABO system), respectively, which reinforced Boyd's contention that inbreeding was unlikely to have produced differences among human groups, contrary to the claims of some anthropologists. Whether any associations existed between blood groups and other traits had long been an issue for physical anthropologists, because most studies found claimed associations inconsistent. Genetic theory, however, would expect associations only if the traits under consideration were genetic, and if they were linked to each other by virtue of being on the same chromosome. Phillip (1944) was able to compare ABO blood types of 1,640 New Zealand soldiers with other traits (dental decay, medical grading, allergy, personality traits) obtained from questionnaires that the soldiers had completed. He found no correlations, which was consistent with expectations of no linkage between the ABO genes and each of the traits examined. Boyd (1949) focused on estimation of admixture from single locus data, and provided examples based on ABO, MN and Rh frequencies of various populations, some calculated by others, and some by himself. Bernstein's method for obtaining these estimates had been known since 1931, thus Boyd focused on the accuracy of single-locus admixture estimates, which depend on the accuracy of the gene frequencies. For the best estimate, he recommended using Fisher's maximum likelihood estimate of gene frequency, which had been successfully employed in admixture studies. He noted, however, that maximum likelihood estimates of Rh gene frequencies were then not possible to calculate, and that some estimates of admixture have large standard errors, which makes their accuracy unlikely. Between the AJPA's founding and the end of World War II a large number of articles had been published that provided phenotype and gene frequency data on a variety of peoples from around the globe. In the majority of cases the articles were purely descriptive, and were no more informative about solving problems on which physical anthropology had been focused since 1918 than were the endless measurements and perfections of technique that were fundamental to Washburn and Detwiler's (1943) complaints. Unfortunately, little could be done with all this genetic data that could be based on new ideas. The heyday of ABO blood grouping coincided with the rise of population genetic theory, which explained in the language of mathematics how evolution proceeds, but which few biologists understood (Ayala & Fitch, 1997). Furthermore, it was not until 1937 that Theodosius Dobzhansky published Genetics and the Origin of Species, which pulled together Darwinian evolution, population genetics, natural history and experimental biology in a way that made sense to biologists (Ayala & Fitch, 1997). With the beginning of the era of the "modern synthesis," geneticists publishing in the AJPA were emboldened. The one thing that did not change quickly was the biological race concept. Dobzhansky saw no reason to do away with the notion of biological race, since race was used successfully to classify geographically variant members of other polytypic animal species. Although his views shifted later, in the 1940s, he thought that "geographical races" existed in H sapiens (Gannett, 2013). His influence had impact on eminent scientists like WC Boyd (1940), and his thought was again displayed in Boyd's essay in the Southwestern Journal of Anthropology (1947), which was much more didactic in style and certainly more combative. Boyd not only continued to assume that "race" was a biologically meaningful concept but he also proclaimed that anthropometry and craniometry were useless in defining racial categories in contrast to the utility of blood groups. He enumerated the many reasons why gene frequencies were optimal traits to employ in classification, and stated that they would best elucidate the "mode and path" of human descent (Boyd, 1949, p. 44), Boyd's (1947) position has been considered typical of the claimed arrogance displayed by geneticists since blood group studies began (Marks, 2012). In his criticism Marks stated that the work in serology led to an "asymmetrical intellectual relationship" between physical anthropology and genetics. He was angered by geneticists' dismissal of information on human classification gleaned from anatomical data and their failure to "take the time and effort to acquire … anthropological grounding" (Marks, 1996, p. 361). He was annoyed by geneticists who claimed genetic data superior to others kinds, and yet failed to see their circularity of reasoning when they compared distributions of genes in groups identified on the basis of morphology. Gannett and Griesmer (2004), on the other hand, think that "objectivity with judgment"—a form of circularity—is necessary if one wants to map the global distribution of ABO gene frequencies. The examples listed above also show that scientists like WC Boyd (1941) were familiar with at least some anthropological concepts (e.g., endogamy versus inbreeding) and were knowledgeable enough to hold membership in the American Association of Anthropologists, as well as serve as Associate Editors of the AJPA. I think a more relevant explanation of Boyd's combative attitude (1947) lies in the conflicts of his times. Just four years earlier Howells (1943) had remarked on the philosophical split within physical anthropology, which had placed the geneticists on one side, and the biometricians on the other. The two groups reflected the bitter divergence between the proponents of the two approaches to understanding human evolution—William Bateson on the side of genetics, and Karl Pearson on the side of biometrics. Howells regarded American physical anthropology as broad enough to house both schools of thought, and he observed that some students were already undertaking genetic research. Nevertheless, historians of science such as Barkan (1992) have underscored the troubled state of affairs in anthropology and in biology as well as within their subdisciplinary components, which had a detrimental impact on their scientific advancements. It seems likely then that Boyd's exposition in 1947 was a barometer regarding the climate of opinion held by different schools of thought about human heredity, not just the best way to identify human "races." Then as now, one could argue that "Big Man" personalities can facilitate as much as retard disciplinary developments, but I think it is wiser to let Howells have his say on the matter: He described William C Boyd, as "a hard-working blood group man" (Howells, 1992, p. 11), who understood the genetics of the evolutionary process well, and did not mince words "plowing under" ideas of race and type that then existed. Boyd, however, with his background in immunology, got under physical anthropologists' skin, as he was "not one of the boys," though he was a major force, and eventually won over others, including Howells himself (Howells, 1992). Howell's generous summary notwithstanding, William C Boyd, who knew more than anyone else among his contemporaries about anthropological genetics, truly believed that morphologically-based classifications of humanity should be replaced by classifications based on gene frequency distributions. His view focused on the fact that morphometric traits are subject to modification based on lifestyle (environment), in contrast to genetic traits. It seems not to have occurred to him that perhaps the problem lay not with the traits used to classify, but with the notion of clas