Everyone Is African (3 page)

The
Lebensborn
(wellspring of life) program was a secretive Nazi effort to develop a superior human race through direct and intentional human breeding. Instituted at the same time as the Nuremberg laws in 1935 and managed by Heinrich Himmler, the program aimed to identify women and men considered to be racially pure Nordic Aryans—mostly young women who applied to the program and passed the racial superiority screening test
and SS soldiers who served as the biological male parents. Himmler decreed that SS soldiers should father as many
Lebensborn
children as possible; marriage was not required. The children were to be raised in
Lebensborn
homes, furnished with loot from Jewish homes. As many as 17,500 children were born under the program, most placed with adoptive families after the war.
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As these secret actions were uncovered after World War II, eugenics laws fell into disrepute and were eventually repealed or left unenforced. By then, however, more than sixty thousand people had been involuntarily sterilized in the United States under such laws.
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Although some antimiscegenation laws were repealed, many remained in force well after the end of World War II, a result of belief that racial purity should be maintained. In the United States, the legality of those laws came to a dramatic and definitive end in the Supreme Court case
Loving v. Virginia
, recounted at the beginning of this chapter.

Antimiscegenation and eugenics laws stem from the notion that superior racial purity should be preserved, similar to maintenance of genetic purity in breeds of domesticated animals. Although similar patterns of inheritance are evident in animals and humans, there are some crucial flaws in assuming that breeds of animals equate to so-called human races. First, humans have intentionally bred domesticated animals to achieve the true-breeding characteristics that purebred animals have, resulting in extremes of variability among breeds—and uniformity within them—that vastly exceed the extremes of natural variation in humans. In dogs, for example, Chihuahuas and Great Danes differ by extremes in size, variation that far outweighs the outward variation among humans, and those extremes are a direct result of intensive breeding. Although restrictions on mating have been a part of various human cultures for most of history, humans have never been subjected to the type of intense selection for extreme types that is typical in animal breeding. Geographic proximity and cultural traditions—not intentional breeding—have historically been the most powerful factors influencing choice of mates in humans.

A second flaw in equating human races to animal breeds is that, historically and especially in modern times, humans have been a highly mobile species. Although some degree of historic reproductive isolation is responsible for part of the geographic distribution of genetic diversity in humans, there
is evidence in our DNA that major and complex human migrations have dispersed, and continue to disperse, much of the genetic diversity in our species.
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These and other factors have ensured that the lines separating the worldwide geographic groups of humans are so blurred they are impossible to define. Harvard professor and geneticist Richard Lewontin describes his perception of the situation quite succinctly:

Racial classification is an attempt to codify what appear to be obvious nodalities in the distribution of human morphological and cultural traits. The difficulty, however, is that despite the undoubted existence of such nodes in the taxonomic space, populations are sprinkled between the nodes so that boundary lines must be arbitrary.
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The article by Lewontin from which this quote is extracted bears the title “The Apportionment of Human Diversity,” and it is one of the most foundational and misconstrued articles ever published on the biological basis of race in humans. Before the 1960s and ‘70s, scientists had few methods available to confidently examine genetic diversity among people. They based estimates of diversity largely on appearance, making assumptions about how much diversity was inherited and how much was a consequence of nongenetic, often termed environmental, variation. Moreover, much of the assessment of human diversity was biased, as Lewontin puts it, by “those characters to which human perceptions are most finely tuned (nose, lip, and eye shapes, skin color, hair form and quantity).”
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Variation for such traits represents only a small subset of overall human genetic diversity, and they are used for classification largely because they are the varying characteristics our brains are attuned to most readily recognize—and those we consciously or unconsciously associate with the geographic ancestries of different people. Other outward characteristics that vary among people do not fall neatly within traditional racial categories.

Adult body height, for example, is genetically determined to a large extent, and it varies considerably among people from all regions of the world. If we were to segregate people by height, there would be little association along traditional lines of racial classification. The tallest people in the world, on average, are the Dutch, and among the tallest are the Masai of East Africa.
Several indigenous groups living in tropical regions of the world are substantially shorter on average, including the Mbenga, Mbuti, and Twa of Africa; the Andamanese, Aeta, Batak, Rampasasa, Semang, and Taron of south and Southeast Asia; the Djabugay of Australia; and the Yąnomamö of Amazonian South America. The genetic basis for some of these extremes in stature has been well documented and is likely a consequence of natural selection.
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Clearly, these variations in height do not mirror traditional racial or geographic classification schemes.

As another obvious example, pattern baldness is a common inherited trait that varies among people (mostly in men and to a lesser extent in women) whose ancestries trace to various parts of the world. Although readily visible, and less prevalent in certain regions of the world than in others, variation for pattern baldness has never been a criterion for racial classification. It makes no sense to lump those with pattern baldness into one racial classification and those without it into another. Only a subset of genetically determined traits that vary in humans is correlated with geographic regions of ancestry.

Other inherited characteristics that are not outwardly apparent, such as blood types and other biochemical traits, vary among people. It is, of course, impossible to tell simply by looking at someone what her or his blood type is, but it is possible to precisely identify blood types and other inherited biochemical traits through laboratory analysis. By the 1970s, scientists had developed methods that allowed them to quantify some of this unseen genetic diversity with exceptionally high accuracy. Lewontin asked whether such biochemical diversity was correlated with traditional racial classifications. In other words, were the physical variations people tend to associate with different races borne out in the precise genetic variations scientists could measure in the laboratory?

His conclusion was shocking—unexpected in its magnitude—and has shaken the foundation of racial classification ever since its publication. Lewontin examined data from seventeen different genes in people classified into seven groups by geographic origin, as named in his article: Amerinds, Australian Aborigines, Black Africans, Caucasians, Mongoloids, Oceanians, and South Asian Aborigines. He found that the degree of genetic variation
within
each group exceeded that
between
different groups. In other words,
people within a particular racial group varied more among themselves than their overall group varied from other groups. On average, according to his calculation, 85 percent of overall genetic diversity fell within groups, whereas only 15 percent could be attributed to between-group differences. He also noted that “the difference between populations within a race accounts for an additional 8.3%, so that only 6.3% is accounted for by racial classification.”
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As an example, A, B, AB, and O blood types vary within the groups identified by Lewontin, albeit not in the same proportions within each group. For instance, all four types are present within the European group and the African group, with type O being the most prevalent within both groups, albeit more prevalent within the African group. Because all four types are present within both groups, a person whose ancestry is European might be incompatible as a potential blood donor for another person with European ancestry, whereas a person with African ancestry may be a compatible donor. In fact, blood banks in hospitals currently identify blood based only on biochemical blood typing, with no reference to racial identification of donors (although this has not always been the case).
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Lewontin's analysis rapidly gained popularity, for it seemed to provide a scientific case against a biological basis for racial inequality, and the political timing was right. When Lewontin's article was published in 1972, the civil rights movement in the United States had by then gained considerable political support and was a frequent issue in the news. Lewontin's article was often cited then, as it is now, as evidence that there is scant scientific basis for racial classification. Such classification was said to be more social than biological.

Thus, it was quite a turnaround in 2003 when Cambridge University professor A. W. F. Edwards, one of the world's foremost statisticians and population geneticists, published a counter-article titled “Human Genetic Diversity: Lewontin's Fallacy.” Edwards makes it clear that “there is nothing wrong with Lewontin's statistical analysis of variation, only with the belief that it is relevant to classification.”
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Edwards points out that Lewontin examined each of seventeen genes independently, but that an assumption of independence was unwarranted; variation for one gene may be correlated with variation for another, and such correlations must be taken into account when using such data for classification. As a simple example, Edwards points to a common practice in anthropology of measuring the length (back to front) and breadth
(side to side) of skulls. It is possible to focus on length and breadth independently and determine variation for each among human skulls without reference to the other. But doing so misses the important point that the two are correlated; an increase in overall skull size results in a concomitant increase in
both
length and breadth. Edwards then highlights a number of studies of human genetic diversity that take such correlation into account. The correlation is essential for describing human genetic diversity and systems intended to classify such diversity.

Challenging a number of published statements based on Lewontin's research, Edwards emphatically concludes,

It is not true [as Lewontin claimed] that “racial classification is…of virtually no genetic or taxonomic significance.” It is not true, as
Nature
claimed, that “two random individuals from any one group are almost as different as any two random individuals from the entire world,” and it is not true, as the
New Scientist
claimed, that “two individuals are different because they are individuals, not because they belong to different races” and that “you can't predict someone's race by their genes.” Such statements might only be true if all the characters studied were independent, which they are not.
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So who is right? When Lewontin did his analysis in 1972, the number of people and the number of genes he examined were just a minuscule fraction of the number of people and genes that have been studied today. More extensive research has confirmed the conclusions of
both
Lewontin and Edwards—negating, however, many of the claims that others inferred from Lewontin's results. In 2004, human geneticists Lynn Jorde and Stephen Wooding of the University of Utah School of Medicine summarized the results from several large-scale studies. First, they confirmed that humans as a species are much less diverse than many other species. According to their estimates, people worldwide differ on average by about 0.1 percent, evidence that all humans are genetically quite similar to one another. They then confirmed Lewontin's major conclusion:

Of the 0.1% of DNA that varies among individuals, what proportion varies among the main populations? Consider an apportionment of Old World
populations into three continents (Africa, Asia, and Europe), a grouping that corresponds to a common view of three of the “major races.” Approximately 85–90% of genetic variation is found within these continental groups, and only an additional 10–15% of the variation is found between them…. These estimates…tell us that humans vary only slightly at the DNA level and that only a small proportion of this variation separates continental populations.
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The accumulation of information from many individuals and their DNA also revealed correlations that correspond with the three major continents of geographic ancestry. In all cases, Jorde and Wooding were able to accurately assign native Europeans, east Asians, and sub-Saharan Africans (Africans whose ancestral origin is south of the Sahara) to their respective continents of origin even when the samples were examined for DNA variation alone without taking into account any other characteristic.

The authors were quick to point out, however, that their data
do not
support the traditional boundaries of race:

[I]t might be tempting to conclude that genetic data verify traditional concepts about races. But the individuals used in these analyses originated in three geographically discontinuous regions: Europe, sub-Saharan Africa, and east Asia. When a sample of South Indians, who occupy an intermediate geographic position, is added to the analysis, considerable overlap is seen among these individuals and both the east Asian and European samples, probably as a result of numerous migrations from various parts of Eurasia into India during the past 10,000 years. Thus the South Indian individuals do not fall neatly into one of the categories usually conceived as a “race.”…Ancestry, then, is a more subtle and complex description of an individual's genetic makeup than is race.
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