Everyone Is African

by Daniel J. Fairbanks

  Some argue that DNA evidence of the type highlighted in this book reinforces rather than invalidates traditional racial classifications. As a recent example, Nicholas Wade, in his book A Troublesome Inheritance: Genes, Race and Human History, writes,

  Even when it is not immediately obvious what race a person belongs to from bodily appearance, as may often be the case with people of mixed-race ancestry, race can nonetheless be distinguished at the genomic level. With the help of ancestry informative markers,…an individual can be assigned with high confidence to the appropriate continent of origin. If of admixed race, like many African Americans, each block of the genome can be assigned to forebears of African or European ancestry. At least at the level of continental populations, races can be distinguished genetically, and this is sufficient to establish that they exist.3

  The ability to distinguish African and European DNA segments in African Americans does not imply the existence of discrete races when the distribution of human genetic diversity is considered on a worldwide basis. It reflects, instead, the historical juxtaposition of people whose ancestral backgrounds trace to the discontinuous places of western Africa and northern Europe as a consequence of European colonization and the Atlantic slave trade in North America.

  Given the vast amount of human genetic information currently available, traditional racial classifications constitute an oversimplified way to represent the distribution of genetic variation among the people of the world. Mutations have been creating new DNA variants throughout human history, and the notion that a small proportion of them define human races fails to recognize the complex nature of their distribution. A large proportion of variants are very ancient, having arisen more than one hundred thousand years ago in Africa when all people lived there, and are now spread throughout the worldwide human population. These variants have been dispersed over tens of thousands of years as people migrated in myriad ways within Africa, out of Africa, back into Africa, and across the other habitable continents. Other variants display clinal patterns, gradually decreasing in prevalence from a central region. They originated in that region and then were dispersed in people who, over generations, migrated away. Yet other variants tend to be clustered in particular regions, often when barriers such as oceans or mountain ranges inhibited their dispersal during periods of history when people were unable or unlikely to migrate across those barriers. Furthermore, natural selection has resulted in increased prevalence of particular variants in certain parts of the world when those variants conferred an advantage for survival and reproduction. Variants influencing pigmentation or resistance to infectious diseases are prominent examples. In addition, the degree of human genetic diversity varies throughout the world and thus cannot provide a reliable way of classifying humans into particular races on the basis of how much or how little diversity is present. Not surprisingly, genetic diversity is highest by far in sub-Saharan Africa where humans originated. Last, widespread human mobility over the past several millennia has reshuffled the world's genetic diversity in complex ways, negating simplistic preconceptions of so-called pure and mixed races.

  The concept of distinct human races as biologically valid groupings was widely accepted prior to the latter part of the twentieth century. It is now outdated, replaced by the more complex and scientifically reliable characterization of genetic ancestry. Some who still cling to the idea of genetically defined races cite evidence that some ancestry informative markers tend to cluster with one another in correlation with geography. Noah Rosenberg of the University of Michigan and his colleagues have conducted some of the most extensive research on such clustering and have made it clear that “our evidence for clustering should not be taken as evidence of our support for any particular concept of ‘biological race.’”4 Notably, some of the world's most prominent human population geneticists have publicly criticized the people who claim genetic research supports the notion of biological races, and the unfounded inferences derived from that notion.5

  Why should an accurate understanding of our genetic unity and diversity matter? First, there are practical reasons. Variations in health are, in part, a consequence of variations in our DNA. The tendency, however, to associate particular medical conditions with race is often overly simplistic and scientifically flawed. A number of genetic conditions, such as cystic fibrosis and sickle cell anemia, are more prevalent in people whose ancestry traces to particular parts of the world, but conditions such as these are not confined to a particular group, and they are rare in all groups. They should never be labeled as racial diseases.

  Dealing with health-related susceptibilities is complex. Genetically inherited differences in skin pigmentation, for example, are inversely correlated with susceptibility to malignant melanoma, the most deadly form of skin cancer. Those with less skin pigmentation are more susceptible than those with greater skin pigmentation. Seemingly racial differences for other susceptibilities, however, may have a much greater social than genetic foundation. Susceptibility to alcoholism in Native Americans, for instance, may have more to do with poverty and poor living conditions than with genetic ancestry.

  In this context, race or ethnicity as a social construct can have medical significance. Differences in socioeconomic status, education, quality of healthcare, health practices, substance abuse, infectious disease, and other nongenetic factors may be responsible for at least some of the difference in health conditions among socially defined ethnic groups. In such cases, efforts to overcome poverty, unemployment or underemployment, and educational inequalities are likely to have a commensurate effect on improving overall health.

  The same can be said for educational attainment. So-called racial differences in IQ scores are more a consequence of disparities in socioeconomic status and the quality of education than of any genetic differences between ethnic groups. Efforts to improve educational quality and opportunity can increase the economic benefits associated with increased educational achievement. As an educator who often works with first-generation college students, I have seen firsthand the transformation that a well-designed education can generate for those who are economically disadvantaged or lack an adequate educational background.

  Beyond the practical reasons, there are perhaps equally important reasons why a scientifically based understanding of human diversity matters. It dispels notions of racial superiority and evokes a sense of wonder and respect for the variety, both genetic and cultural, of the world's human population, from our African origins to the present. Perhaps most important, it tells us who we are and how we originated.

  Unfortunately, many people find it difficult to accept what current science tells us about the myth of race. It runs counter to what seem to be obvious racial distinctions, mostly in parts of the world where immigration history has juxtaposed people with discontinuous ancestral backgrounds in the same place. The racial categorizations that many of us have experienced throughout our lives have likewise inculcated a sense of racial division that is not easy to abandon. Regardless of what the scientific evidence shows, the perception of race and the associated racial discrimination are unlikely to disappear anytime soon. Furthermore, a scientific understanding of human evolutionary history challenges commonly held religious beliefs that are based on literal interpretations of biblical history. Everything we have discussed in this book, and everything related to human genetic diversity, is a consequence of our evolutionary history, supported by abundant evidence. Just as geneticist Theodosius Dobzhansky famously affirmed that “nothing in biology makes sense except in the light of evolution,” nothing we know about human genetic diversity makes sense except in the light of human evolution.6 Yet a significant minority of people (42 percent in the United States, according to the most recent Gallup poll) fully reject human evolution, opting instead for the belief that humans were specially created with no prior evolutionary ancestry less than ten thousand years ago.7 Such beliefs are often infused with a nonscientific perception of different races and how they supposedly origina
ted. And, in spite of overwhelming scientific evidence and changing social norms, a relatively large proportion of people still cling to past traditions of white supremacy and racism.

  To understand who we are as a species, and why we vary as we do, we must examine our genetic diversity in the context of a common African origin, followed by intra- and intercontinental diasporas that transpired over a period of tens of thousands of years, culminating in an era of major migrations that reshuffled the worldwide human genetic constitution over the past several thousand years and is still underway. Last, we must recognize that today's human population is far larger, more diverse, and more complex than it ever has been. We are all related, more than seven billion of us, distant cousins to one another, and, ultimately, everyone is African.

  PREFACE

  1. R. J. Sternberg, “Intelligence,” Dialogues in Clinical Neuroscience 14, no. 1 (2012): 19–27.

  2. British Broadcasting Corporation (BBC), “Episode 3: A Savage Legacy,” Racism: A History, 58:47, http://topdocumentaryfilms.com/racism-history (accessed June 25, 2014), 58:02.

  3. Ibid., 55:40.

  4. A. James, “Making Sense of Race and Racial Classification,” in White Logic, White Methods: Racism and Methodology, ed. T. Zuberi et al. (Lanham, MD: Rowman and Littlefield, 2008), p. 32.

  5. BBC, Racism: A History, http://topdocumentaryfilms.com/racism-history (accessed June 25, 2014); Public Broadcasting System, Race: The Power of an Illusion, http://www.pbs.org/race (accessed June 25, 2014).

  CHAPTER 1: WHAT IS RACE?

  1. As quoted by E. Warren, “Loving v. Virginia: Opinion of the Court,” No. 395, 206 Va. 924, 147 S.E.2d 78, reversed, http://www.law.cornell.edu/supct/html/historics/USSC_CR_0388_0001_ZO.html (accessed July 15, 2014).

  2. Ibid.

  3. Ibid.

  4. T. Head, “Interracial Marriage Laws: A Short Timeline History,” http://civilliberty.about.com/od/raceequalopportunity/tp/Interracial-Marriage-Laws-History-Timeline.htm (accessed May 14, 2013).

  5. South Africa Parliament, Report of the Joint Committee on the Prohibition of Mixed Marriages Act and Section 16 of the Immorality Act (Cape Town, South Africa: Government Printer, 1985).

  6. C. R. Darwin, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, 4th ed. (London: John Murray, 1866), p. 16.

  7. C. R. Darwin, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, 5th ed. (London: John Murray, 1869), p. 243.

  8. American Kennel Club, “Breed Matters,” https://www.akc.org/breeds (accessed May 3, 2014).

  9. C. R. Darwin, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, 1st ed. (London: John Murray, 1859), p. 298.

  10. R. C. Punnett, Mendelism (New York: Macmillan, 1905), p. 184.

  11. United States Holocaust Memorial Museum, “Holocaust Encyclopedia,” http://www.ushmm.org/wlc/en/article.php?ModuleId=10005143 (accessed July 16, 2012).

  12. Jewish Virtual Library, “The Nazi Party: The ‘Lebensborn’ Program,” http://www.jewishvirtuallibrary.org/jsource/Holocaust/Lebensborn.html (accessed July 16, 2012).

  13. A. M. Stern, Eugenic Nation: Faults and Frontiers of Better Breeding in Modern America (Oakland, CA: University of California Press, 2005), p. 244.

  14. G. Hellenthal et al., “A Genetic Atlas of Human Admixture History,” Science 343, no. 6172 (2014): 747–51.

  15. R. C. Lewontin, “The Apportionment of Human Diversity,” Evolutionary Biology 6 (1972): 385.

  16. Ibid., p. 382.

  17. J. P. Jarvis et al., “Patterns of Ancestry, Signatures of Natural Selection, and Genetic Association with Stature in Western African Pygmies,” PLoS Genetics 8, no. 4 (2012): e1002641.

  18. Ibid.

  19. S. E. Lederer, Flesh and Blood: Organ Transplantation and Blood Transfusion in 20th Century America (Oxford: Oxford University Press, 2008).

  20. A. W. F. Edwards, “Human Genetic Diversity: Lewontin's Fallacy,” BioEssays 25, no. 8 (2003): 800.

  21. Ibid., p. 801.

  22. L. B. Jorde and S. P. Wooding, “Genetic Variation, Classification, and ‘Race,’” Nature Genetics 36 (2004): S28.

  23. Ibid., p. S30.

  CHAPTER 2: AFRICAN ORIGINS

  1. The evidence of this ancient population is human skeletal remains, including nearly intact skulls bearing the features of modern humans, in the Qafzeh and Skhul caves. See C. B. Stringer et al., “ESR Dates for the Hominid Burial Site of Es Skhul in Israel,” Nature 338 (1989): 756–58.

  2. D. J. Fairbanks, Evolving: The Human Effect and Why It Matters (Amherst, NY: Prometheus Books, 2012).

  3. Ibid.

  4. R. E. Green et al., “A Draft Sequence of the Neanderthal Genome,” Science 328, no. 7929 (2010): 710–22.

  5. J. Zhang et al., “Genomewide Distribution of High-Frequency, Completely Mismatching SNP Haplotype Pairs Observed to Be Common across Human Populations,” American Journal of Human Genetics 73, no. 5 (2003): 1073–81.

  6. L. B. Jorde and S. P. Wooding, “Genetic Variation, Classification, and Race,” Nature Genetics 36 (2004): S28–S33.

  7. There is one documented instance of paternal inheritance of mitochondrial DNA in humans, and it is due to a genetic disorder. The man who inherited this DNA had the paternal mitochondrial DNA only in his muscles. The mitochondrial DNA in the rest of his body was maternal, so this single documented instance of paternal transmission of mitochondrial DNA has no effect on pure maternal inheritance throughout generations. The research was published by M. Schwartz and D. Vissing, “Paternal Inheritance of Mitochondrial DNA,” New England Journal of Medicine 347, no. 8 (2002): 576–80.

  8. M. Ingman et al., “Mitochondrial Genome Variation and the Origin of Modern Humans,” Nature 408, no. 6828 (2000): 708–13; N. van Oven and M. Kayser, “Updated Comprehensive Phylogenetic Tree of Global Human Mitochondrial DNA Variation,” Human Mutation 30, no. 2 (2009): E386–94; P. Soares et al., “Correcting for Purifying Selection: An Improved Human Mitochondrial Molecular Clock,” American Journal of Human Genetics 84, no. 6 (2009): 740–59.

  9. U. A. Perego et al., “Distinctive Paleo-Indian Migration Routes from Beringia Marked by Two Rare mtDNA Haplogroups,” Current Biology 13, no. 1 (2009): 1–8.

  10. S. A. Elias, “Late Pleistocene Climates of Beringia, Based on Analysis of Fossil Beetles,” Quaternary Research 53, no. 2 (2000): 229–35.

  11. B. Malyarchuk et al., “The Peopling of Europe from the Mitochondrial Haplogroup U5 Perspective,” PLoS ONE 5, no. 4 (2010): e10285.

  12. D. M. Behar et al., “A ‘Copernican’ Reassessment of the Human Mitochondrial DNA Tree from Its Root,” American Journal of Human Genetics 90, no. 4 (2012): 675–84.

  13. Soares et al., “Correcting for Purifying Selection.”

  14. In reality, a very small part on one end of the Y chromosome recombines with the X chromosome. However, all genetic analysis for ancestry is done with the nonrecombining portion, which represents the vast majority of the Y chromosome.

  15. F. Cruciani et al., “A Revised Root for the Human Y Chromosomal Phylogenetic Tree: The Origin of Patrilineal Diversity in Africa,” American Journal of Human Genetics 88, no. 6 (2011): 814–18.

  16. W. Fu et al., “Analysis of 6,515 Exomes Reveals the Recent Origin of Most Human Protein-Coding Variants,” Nature 493, no. 7431 (2013): 216–20.

  17. Jorde and Wooding, “Genetic Variation, Classification, and Race,” p. S29.

  CHAPTER 3: ANCESTRY VERSUS RACE

  1. For an excellent summary of the Jefferson-Hemings history and research, see the PBS Frontline episode “Mapping Jefferson's Y Chromosome” at http://www.pbs.org/wgbh/pages/frontline/shows/jefferson/etc/genemap.html (accessed November 11, 2012). For more detailed information, and the results of original research, see F. L. Mendez et al., “Increased Resolution of Y Chromosome Haplogroup T Defines Relationships among Pop
ulations of the Near East, Europe, and Africa,” Human Biology 83, no. 1 (2011): 39–53; Thomas Jefferson Memorial Foundation, Report of the Research Committee on Thomas Jefferson and Sally Hemings, http://www.monticello.org/sites/default/files/inline-pdfs/jefferson-hemings_report.pdf (accessed November 11, 2012); National Public Radio, “Thomas Jefferson Descendants Work to Heal Family's Past,” http://www.npr.org/templates/story/story.php?storyId=131243217 (accessed November 11, 2012); A. G. Reed, The Hemingses of Monticello: An American Family (New York: W. W. Norton, 2009).

  2. D. M. Goldenberg, The Curse of Ham: Race and Slavery in Early Judaism, Christianity, and Islam (Princeton, NJ: Princeton University Press, 2003).

  3. Ibid.

  4. S. J. Gould, The Mismeasure of Man, rev. ed. (New York: W. W. Norton, 1996), p. 404.

  5. United States Census Bureau, “Race,” http://www.census.gov/topics/population/race.html (accessed June 25, 2014).

  6. M. F. Hammer et al., “Population Structure of Y Chromosome SNP Haplogroups in the United States and Forensic Implications for Constructing Y Chromosome STR Databases,” Forensic Science International 164, no. 1 (2006): 45–55.

  7. D. J. Fairbanks et al., “NANOGP8: Evolution of a Human-Specific Retro-Oncogene,” G3: Genes Genomes Genetics 2, no. 11 (2012): 1447–57; D. J. Fairbanks and P. J. Maughan, “Evolution of the NANOG Pseudogene Family in the Human and Chimpanzee Genomes,” BMC Evolutionary Biology 6 (2006): 12.