Scientists Call for End to Race Denial

Let's celebrate human genetic diversity

Bruce Lahn and Lanny Ebenstein
Nature, 8 October 2009

Science is finding evidence of genetic diversity among groups of people as well as among individuals. This discovery should be embraced, not feared, say Bruce T. Lahn and Lanny Ebenstein.

A growing body of data is revealing the nature of human genetic diversity at increasingly finer resolution. It is now recognized that despite the high degree of genetic similarities that bind humanity together as a species, considerable diversity exists at both individual and group levels (see box, page 728). The biological significance of these variations remains to be explored fully. But enough evidence has come to the fore to warrant the question: what if scientific data ultimately demonstrate that genetically based biological variation exists at non-trivial levels not only among individuals but also among groups? In our view, the scientific community and society at large are ill-prepared for such a possibility. We need a moral response to this question that is robust irrespective of what research uncovers about human diversity. Here, we argue for the moral position that genetic diversity, from within or among groups, should be embraced and celebrated as one of humanity's chief assets.

The current moral position is a sort of 'biological egalitarianism'. This dominant position emerged in recent decades largely to correct grave historical injustices, including genocide, that were committed with the support of pseudoscientific understandings of group diversity. The racial-hygiene theory promoted by German geneticists Fritz Lenz, Eugene Fischer and others during the Nazi era is one notorious example of such pseudoscience. Biological egalitarianism is the view that no or almost no meaningful genetically based biological differences exist among human groups, with the exception of a few superficial traits such as skin colour. Proponents of this view seem to hope that, by promoting biological sameness, discrimination against groups or individuals will become groundless.

We believe that this position, although well intentioned, is illogical and even dangerous, as it implies that if significant group diversity were established, discrimination might thereby be justified. We reject this position. Equality of opportunity and respect for human dignity should be humankind's common aspirations, notwithstanding human differences no matter how big or small. We also think that biological egalitarianism may not remain viable in light of the growing body of empirical data.

Many people may acknowledge the possibility of genetic diversity at the group level, but see it as a threat to social cohesion. Some scholars have even called for a halt to research into the topic or sensitive aspects of it, because of potential misuse of the information. Others will ask: if information on group diversity can be misused, why not just focus on individual differences and ignore any group variation? We strongly affirm that society must guard vigilantly against any misuse of genetic information, but we also believe that the best defence is to take a positive attitude towards diversity, including that at the group level. We argue for our position from two perspectives: first, that the understanding of group diversity can benefit research and medicine, and second, that human genetic diversity as a whole, including group diversity, greatly enriches our species.

[...]

Box 2. Emerging understanding of human genetic diversity

Genetic diversity is the differences in DNA sequence among members of a species. It is present in all species owing to the interplay of mutation, genetic drift, selection and population structure. When a species is reproductively isolated into multiple groups by geography or other means, the groups differentiate over time in their average genetic make-up.

Anatomically modern humans first appeared in eastern Africa about 200,000 years ago. Some members migrated out of Africa by 50,000 years ago to populate Asia, Australia, Europe and eventually the Americas. During this period, geographic barriers separated humanity into several major groups, largely along continental lines, which greatly reduced gene flow among them. Geographic and cultural barriers also existed within major groups, although to lesser degrees.

This history of human demography, along with selection, has resulted in complex patterns of genetic diversity. The basic unit of this diversity is polymorphisms — specific sites in the genome that exist in multiple variant forms (or alleles). Many polymorphisms involve just one or a few nucleotides, but some may involve large segments of genetic material. The presence of polymorphisms leads to genetic diversity at the individual level such that no two people's DNA is the same, except identical twins. The alleles of some polymorphisms are also found in significantly different frequencies among geographic groups. An extreme example is the pigmentation gene SLC24A5. An allele of SLC24A5 that contributes to light pigmentation is present in almost all Europeans but is nearly absent in east Asians and Africans.

Given these geographically differentiated polymorphisms, it is possible to group humans on the basis of their genetic make-up. Such grouping largely confirms historical separation of global populations by geography. Indeed, a person's major geographic group identity can be assigned with near certainty on the basis of his or her DNA alone (now an accepted practice in forensics). There is growing evidence that some of the geographically differentiated polymorphisms are functional, meaning that they can lead to different biological outcomes (just how many is the subject of ongoing research). These polymorphisms can affect traits such as pigmentation, dietary adaptation and pathogen resistance (where evidence is rather convincing), and metabolism, physical development and brain biology (where evidence is more preliminary).

For most biological traits, genetically based differentiation among groups is probably negligible compared with the variation within the group. For other traits, such as pigmentation and lactose intolerance, differences among groups are so substantial that the trait displays an inter-group difference that is non-trivial compared with the variance within groups, and the extreme end of a trait may be significantly over-represented in a group.

Several studies have shown that many genes in the human genome may have undergone recent episodes of positive selection — that is, selection for advantageous biological traits. This is contrary to the position advocated by some scholars that humans effectively stopped evolving 50,000–40,000 years ago. In general, positive selection can increase the prevalence of functional polymorphisms and create geographic differentiation of allele frequencies.

Link to Abstract

Link to Box 2

Foreigners in Ancient Rome

According to the book Foreigners at Rome: Citizens and Strangers by David Noy (London: Duckworth, 2000), the main sources of foreigners in Ancient Rome were Gaul and Hispania, Central and Eastern Europe, Greece, Asia Minor, Syria, Egypt, North Africa and Jews (p. 205 ff.). However, it seems that most of those from outside of Europe were ethnically Greek, while Jews never fully assimilated into Roman society, and that the city's foreign population at its peak was only ~5%. Also, foreigners (especially slaves) had higher mortality rates and lower birth rates than natives and were sometimes subjected to mass expulsions. Here are some relevant passages from the book:

Population Size

Immigration was essential to Rome both demographically, to increase or at least maintain the size of the city's population, and socially, to provide skilled workers and soldiers. The slave trade met some of the requirements, but free immigrants were always needed. Provincials probably began to outnumber Italians among newcomers to Rome in the first centuries BC and AD. The third century AD, when all recruitment for the Praetorian Guard was done in the provinces, may have seen the numerical peak of Rome's foreign population. It is plausible to suppose that at least 5% of the city's inhabitants were born outside Italy in that period; the reality could be much greater.

Expulsions

Foreigners who did not have Roman citizenship were always liable to summary expulsion from the city, and by the fourth century the possession of citizenship was no longer protection against such treatment. Although there was a certain amount of xenophobia within the Roman literary class, expulsion was only used in certain circumstances: to deal with the actual or potential misdeeds or alleged bad influence of specific groups (which could be defined by nationality, religion or occupation), or to counteract the effect of food shortages by reducing the number of mouths to feed. Expulsions were probably not carried out very efficiently, and were always short-lived.

Mortality Rate

It is generally agreed that mortality was probably higher in Rome than elsewhere in the Roman world, because of insanitary living conditions and the risk of contagious diseases; diseases such as tuberculosis may have been endemic. Newcomers to [17th-18th c.] London were more susceptible to plague than natives were, and the same point has been made about the greater susceptibility of Rome's immigrants to plasmodium falciparum malaria. Tuberculosis might be particularly dangerous to the young adults who probably formed most of the immigrant population. [...] Slaves are likely to have suffered from higher mortality than the free population, and immigrant slaves would have been particularly vulnerable to diseases which were not prevalent in their homelands.

Birth Rate

It is also likely that the birth rate would have been lower at Rome than elsewhere. Many migrants coming to the city would already have spent some of their fertile years elsewhere, and the slave part of the population would have been less fertile than the rest. Free male citizen immigrants may have postponed marriage until they had access to the corn dole, which from the time of Augustus was only available to a restricted number of recipients. In London, for similar reasons, the natives were closer to reproducing themselves than migrants were, and the same would almost certainly have been true for Rome.

Asia Minor

Although literature emphasizes the significance of Asian slaves at Rome, inscriptions present a rather different picture. The large number of epitaphs in Greek, especially for people from the province of Asia, is consistent with the large number of recorded peregrini [foreigners] in suggesting that the migration of people of free status was particularly significant for this area. The evidence is, however, almost exclusively concerned with the Greek population of Asia Minor, and there is very little sign of people of non-Greek background coming to Rome except as slaves. This is consistent with the general predominance of the most romanized/hellenized section of their home society among free migrants to Rome.

Syria

However, most Syrians arrived at Rome through the workings of the slave trade. Syrus was a common slave name, although not necessarily given only to Syrians, since the association Syrian = slave seems to have been very widespread....

"Voluntary migration from Syria to Rome would probably have begun in the late Republic. Most of the evidence, however, is from the second century AD or later. There is a clear implication that some of the slaves and ex-slaves labelled Syrians in the literary sources were thoroughly imbued with Greek culture, whether their ancestry was Syrian, Greek or mixed. Solin (1983, 722) notes that Syrian immigrants in general tended to be of Greek descent or at least to be from the most hellenized part of Syrian society.

Egypt

Most references to Egyptians at Rome concern Alexandrians, apparently of Greek extraction, rather than 'indigenous' Egyptians. On the other hand, the stereotyped Roman image of Egyptians concentrated on the aspects of their behaviour perceived as most outlandish, particularly the worship of animal-gods, and largely ignored the Greek component of their culture. There seems to be something of a contradiction between image and reality which may be due at least in part to anti-Cleopatra propaganda and its legacy.

North Africa

North Africa contained some cities which were Greek, Libyan or Phoenician foundations, but many of the main population centres began as Roman colonies (notably the re-established Carthage) or military settlements. Ricci (1994b, 198) believes that the colonization programme of Julius Caesar and Augustus in North Africa also stimulated a population flow from there to Rome. The inhabitants of the area came from a wide variety of ethnic backgrounds (Italian, Greek, Punic, Libyan, Berber, Jewish), but, as with other areas, it is likely to have been the most romanized/hellenized section of the population which provided most of the free migrants to Rome.

Jews

The group which made the greatest effort to retain a separate identity was the Jews. In their religious and communal institutions, their use of separate catacombs, their epigraphic and liturgical use of Greek, and even their naming practices, they behaved differently from others and were able to pass on a Jewish identity, so that people whose ancestors had lived at Rome for generations and who were otherwise well integrated into Roman society were still identifiably Jewish.

AnthroScape Re-Launch

AnthroScape: Human Biodiversity Forum has reopened. We sincerely apologize for the long delay and hope that you'll join us again. For more information, please begin by reading this topic:

http://s1.zetaboards.com/anthroscape/topic/920112/

Thank you.

AnthroScape: Human Biodiversity Forum

AnthroScape is a new biological and social anthropology forum that picks up where the defunct Dodona left off. Please begin by reading the Mission Statement and Forum Rules.

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We look forward to seeing you there!

Dinaric Alps Home to Tallest Europeans

Average height of adolescents in the Dinaric Alps

Pineau et al. (2005)
C R Biol

ABSTRACT: This study contributes to an update of average heights among European populations. Our investigation covering 2705 boys and 2842 girls aged 17 years, shows that, contrary to the general belief, adolescents of the Dinaric Alps are, on average, the tallest in Europe. With an average height of 185.6 cm, they are taller than Dutch adolescents (184 cm on average). Above all, the density of very tall subjects appears to be characteristic of the Dinaric Alps, since 28% measure 190 cm or more in height, as opposed to only 20% in Holland and 1.5% in France. Although our information is not complete, adolescent girls in the Dinaric Alps, with an average height of 171 cm, come a close second to girls in Holland.

[NB: Samples were taken from six locations in Dalmatia (southern Croatia) and three in Herzegovina.]

Link

Nazi Poster Boy Was Jewish

The secret history of the Nazi mascot

By Nick Bryant
BBC News, Melbourne
Tuesday, 21 August 2007



In newsreels, he was paraded as 'the Reich's youngest Nazi' and he witnessed some unspeakable atrocities.

But his SS masters never discovered the most essential detail about his life: their little Nazi mascot was Jewish.

"They didn't know that I was a Jewish boy who had escaped a Nazi death squad. They thought I was a Russian orphan."

Read the full story

Another photo

Prognathism and Facial Flatness

This study compares facial characteristics of 112 ancient, medieval and modern populations from around the world. The basic finding is that prognathism (jaw protrusion) is associated with Austro-Melanesians and sub-Saharan Africans, and facial flatness with East Asians, while Europeans, West Asians and North Africans (Caucasoids) generally lack both of these features.

Frontal and Facial Flatness of Major Human Populations

Tsunehiko Hanihara (2000)
Am J Phys Anthro

[...]

The standardized coefficients for the variables of the first factor indicate the relationship between the prominence of the infraglabellar notch, prognathism, and frontal flatness in the sagittal plane and frontoorbital flatness and, to a lesser extent, nasal flatness. The plots of the samples on the first canonical variates, based on the scores of the canonical variables in each sample, are presented in Figures 7a,b. The first variable group (Fig. 7a) opposes the Australian/Melanesian samples to the east/northeast Asian samples. The positive, or Australian/Melanesian end, reflects a relatively prominent infraglabellar notch and marked prognathism with a sagittally flat frontal bone. Some of subSaharan African samples are plotted on the positive or Australian/Melanesian side. On the other hand, the European samples, together with the north African, west Asian, and Indian subcontinent samples, are scattered on the opposed side. Figure 7b indicates the magnitude of the projection of midfacial region in the transverse plane without prognathism. The positive end, reflecting flat fronto-orbital and nasal portions, signals a decided eastern Asian and Pacific configuration together with some subSaharan African samples. The degree of facial projection of some New World samples and Australian samples is comparable to those of samples from south Asia to Europe through west Asia and north Africa.


[ See link below for sample details ]

Discussion

The results presented herein suggest that the features relating to frontal and facial flatness are largely confined to populations from differing world regions: 1) the considerable flatness of the faces of east/northeast Asians, and to a lesser extent, of southeast Asians; 2) morphological complexes such as a deep infraglabellar notch and sagittally flat frontal bone with facial prognathism in Australians and Melanesians; 3) rounded forehead comparable to that in northeast Asians and transversely projecting faces as in Europeans found in the New World populations; 4) eastern Asian-like features in Polynesians and Micronesians, except for a projecting zygomaxillary region; 5) midfacial projection without prognathism in Europeans and related populations such as south and west Asians as well as north Africans; and 6) remarkable prognathism and very flat nasal bones in SubSaharan Africans.

Link (PDF)

Women in Art

500 Years of Female Portraits in Western Art

This is a neat little survey of European aesthetics over the centuries that shows famous paintings morphing into one another chronologically. The music is Bach's Cello Suite No. 1 performed by Yo-Yo Ma.



Link

Biologists Take Definitive Stance in 'Race Debate'

This paper was even written up in the New York Times (with obligatory "opposing view" that doesn't amount to much).

Categorization of humans in biomedical research: genes, race and disease

Neil Risch, Esteban Burchard, Elad Ziv, and Hua Tang
Genome Biology, 2002

[...]

With this as background, it is not surprising that numerous human population genetic studies have come to the identical conclusion - that genetic differentiation is greatest when defined on a continental basis. The results are the same irrespective of the type of genetic markers employed, be they classical systems [5], restriction fragment length polymorphisms (RFLPs) [6], microsatellites [7,8,9,10,11], or single nucleotide polymorphisms (SNPs) [12]. For example, studying 14 indigenous populations from 5 continents with 30 microsatellite loci, Bowcock et al. [7] observed that the 14 populations clustered into the five continental groups, as depicted in Figure 1. The African branch included three sub-Saharan populations, CAR pygmies, Zaire pygmies, and the Lisongo; the Caucasian branch included Northern Europeans and Northern Italians; the Pacific Islander branch included Melanesians, New Guineans and Australians; the East Asian branch included Chinese, Japanese and Cambodians; and the Native American branch included Mayans from Mexico and the Surui and Karitiana from the Amazon basin. The identical diagram has since been derived by others, using a similar or greater number of microsatellite markers and individuals [8,9]. More recently, a survey of 3,899 SNPs in 313 genes based on US populations (Caucasians, African-Americans, Asians and Hispanics) once again provided distinct and non-overlapping clustering of the Caucasian, African-American and Asian samples [12]: "The results confirmed the integrity of the self-described ancestry of these individuals". Hispanics, who represent a recently admixed group between Native American, Caucasian and African, did not form a distinct subgroup, but clustered variously with the other groups. A previous cluster analysis based on a much smaller number of SNPs led to a similar conclusion: "A tree relating 144 individuals from 12 human groups of Africa, Asia, Europe and Oceania, inferred from an average of 75 DNA polymorphisms/individual, is remarkable in that most individuals cluster with other members of their regional group" [13]. Effectively, these population genetic studies have recapitulated the classical definition of races based on continental ancestry - namely African, Caucasian (Europe and Middle East), Asian, Pacific Islander (for example, Australian, New Guinean and Melanesian), and Native American.

[...]

Populations that exist at the boundaries of these continental divisions are sometimes the most difficult to categorize simply. For example, east African groups, such as Ethiopians and Somalis, have great genetic resemblance to Caucasians and are clearly intermediate between sub-Saharan Africans and Caucasians [5]. The existence of such intermediate groups should not, however, overshadow the fact that the greatest genetic structure that exists in the human population occurs at the racial level.

Most recently, Wilson et al. [2] studied 354 individuals from 8 populations deriving from Africa (Bantus, Afro-Caribbeans and Ethiopians), Europe/Mideast (Norwegians, Ashkenazi Jews and Armenians), Asia (Chinese) and Pacific Islands (Papua New Guineans). Their study was based on cluster analysis using 39 microsatellite loci. Consistent with previous studies, they obtained evidence of four clusters representing the major continental (racial) divisions described above as African, Caucasian, Asian, and Pacific Islander. The one population in their analysis that was seemingly not clearly classified on continental grounds was the Ethiopians, who clustered more into the Caucasian group. But it is known that African populations with close contact with Middle East populations, including Ethiopians and North Africans, have had significant admixture from Middle Eastern (Caucasian) groups, and are thus more closely related to Caucasians [14]. Furthermore, the analysis by Wilson et al. [2] did not detect subgroups within the four major racial clusters (for example, it did not separate the Norwegians, Ashkenazi Jews and Armenians among the Caucasian cluster), despite known genetic differences among them. The reason is clearly that these differences are not as great as those between races and are insufficient, with the amount of data provided, to distinguish these subgroups.

Are racial differences merely cosmetic?

Two arguments against racial categorization as defined above are firstly that race has no biological basis [1,3], and secondly that there are racial differences but they are merely cosmetic, reflecting superficial characteristics such as skin color and facial features that involve a very small number of genetic loci that were selected historically; these superficial differences do not reflect any additional genetic distinctiveness [2]. A response to the first of these points depends on the definition of 'biological'. If biological is defined as genetic then, as detailed above, a decade or more of population genetics research has documented genetic, and therefore biological, differentiation among the races. This conclusion was most recently reinforced by the analysis of Wilson et al. [2]. If biological is defined by susceptibility to, and natural history of, a chronic disease, then again numerous studies over past decades have documented biological differences among the races. In this context, it is difficult to imagine that such differences are not meaningful. Indeed, it is difficult to conceive of a definition of 'biological' that does not lead to racial differentiation, except perhaps one as extreme as speciation.

A forceful presentation of the second point - that racial differences are merely cosmetic - was given recently in an editorial in the New England Journal of Medicine [1]: "Such research mistakenly assumes an inherent biological difference between black-skinned and white-skinned people. It falls into error by attributing a complex physiological or clinical phenomenon to arbitrary aspects of external appearance. It is implausible that the few genes that account for such outward characteristics could be meaningfully linked to multigenic diseases such as diabetes mellitus or to the intricacies of the therapeutic effect of a drug." The logical flaw in this argument is the assumption that the blacks and whites in the referenced study differ only in skin pigment. Racial categorizations have never been based on skin pigment, but on indigenous continent of origin. For example, none of the population genetic studies cited above, including the study of Wilson et al. [2], used skin pigment of the study subjects, or genetic loci related to skin pigment, as predictive variables. Yet the various racial groups were easily distinguishable on the basis of even a modest number of random genetic markers; furthermore, categorization is extremely resistant to variation according to the type of markers used (for example, RFLPs, microsatellites or SNPs).

Genetic differentiation among the races has also led to some variation in pigmentation across races, but considerable variation within races remains, and there is substantial overlap for this feature. For example, it would be difficult to distinguish most Caucasians and Asians on the basis of skin pigment alone, yet they are easily distinguished by genetic markers. The author of the above statement [1] is in error to assume that the only genetic differences between races, which may differ on average in pigmentation, are for the genes that determine pigmentation.

Link

Dante Reconstruction

The scientists seem to think their reconstructed bust of Italian Renaissance poet Dante Alighieri looks very different from popular conceptions, but it looks pretty close to me, especially considering that most portraits of him were made after he died, and his "death masks" are likely fakes (i.e. sculptures). Also, he appears older in the reconstruction, which would be accompanied by a softening of his features.




Link to story