Race (human categorization)

===== Cluster analysis =====
A 2002 study of random biallelic genetic loci found little to no evidence that humans were divided into distinct biological groups.<ref>{{cite journal |last1=Romualdi |first1=Chiara |last2=Balding |first2=David |author-link2=David Balding |last3=Nasidze |first3=Ivane S. |last4=Risch |first4=Gregory |last5=Robichaux |first5=Myles |last6=Sherry |first6=Stephen T. |last7=Stoneking |first7=Mark |author-link7=Mark Stoneking |last8=Batzer |first8=Mark A. |author-link8=Mark Batzer |last9=Barbujani |first9=Guido |author-link9=Guido Barbujani |date=April 2002 |title=Patterns of human diversity, within and among continents, inferred from biallelic DNA polymorphisms |journal=Genome Research |volume=12 |issue=4 |pages=602–612 |doi=10.1101/gr.214902 |issn=1088-9051 |pmid=11932244 |pmc=187513}}</ref>

In his 2003 paper, "[[Human Genetic Diversity: Lewontin's Fallacy]]", [[A. W. F. Edwards]] argued that rather than using a locus-by-locus analysis of variation to derive taxonomy, it is possible to construct a human classification system based on characteristic genetic patterns, or ''clusters'' [[Race and genetics#Structure|inferred from multilocus genetic data]].<ref name="edwards" /><ref name="Dawkins & Wong"/> Geographically based human studies since have shown that such genetic clusters can be derived from analyzing of a large number of loci which can assort individuals sampled into groups analogous to traditional continental racial groups.<ref name="Harpending; et al." />{{sfn|Tang|Quertermous|Rodriguez|Kardia|2005}} Joanna Mountain and [[Neil Risch]] cautioned that while genetic clusters may one day be shown to correspond to phenotypic variations between groups, such assumptions were premature as the relationship between genes and [[complex traits]] remains poorly understood.<ref name="mountain" /> However, Risch denied such limitations render the analysis useless: "Perhaps just using someone's actual birth year is not a very good way of measuring age. Does that mean we should throw it out?&nbsp;... Any category you come up with is going to be imperfect, but that doesn't preclude you from using it or the fact that it has utility."<ref name="gitschier" />

Early human genetic cluster analysis studies were conducted with samples taken from ancestral population groups living at extreme geographic distances from each other. It was thought that such large geographic distances would maximize the genetic variation between the groups sampled in the analysis, and thus maximize the probability of finding cluster patterns unique to each group. In light of the historically recent acceleration of human migration (and correspondingly, human gene flow) on a global scale, further studies were conducted to judge the degree to which genetic cluster analysis can pattern ancestrally identified groups as well as geographically separated groups. One such study looked at a large multiethnic population in the United States, and "detected only modest genetic differentiation between different current geographic locales within each race/ethnicity group. Thus, ancient geographic ancestry, which is highly correlated with self-identified race/ethnicity&nbsp;– as opposed to current residence&nbsp;– is the major determinant of genetic structure in the U.S. population."{{sfn|Tang|Quertermous|Rodriguez|Kardia|2005}}

{{harvtxt|Witherspoon|Wooding|Rogers|Marchani|2007}} have argued that even when individuals can be reliably assigned to specific population groups, it may still be possible for two randomly chosen individuals from different populations/clusters to be more similar to each other than to a randomly chosen member of their own cluster. They found that many thousands of genetic markers had to be used in order for the answer to the question "How often is a pair of individuals from one population genetically more dissimilar than two individuals chosen from two different populations?" to be "never". This assumed three population groups separated by large geographic ranges (European, African and East Asian). The entire world population is much more complex and studying an increasing number of groups would require an increasing number of markers for the same answer. The authors conclude that "caution should be used when using geographic or genetic ancestry to make inferences about individual phenotypes".<ref name="Witherspoon, et al. 2007" /> Witherspoon, et al. concluded: "The fact that, given enough genetic data, individuals can be correctly assigned to their populations of origin is compatible with the observation that most human genetic variation is found within populations, not between them. It is also compatible with our finding that, even when the most distinct populations are considered and hundreds of loci are used, individuals are frequently more similar to members of other populations than to members of their own population."<ref name="Witherspoon, et al. 2007" />

Anthropologists such as [[C. Loring Brace]],<ref name="Brace 2005" /> the philosophers Jonathan Kaplan and Rasmus Winther,<ref name="encyclopedia" /><ref>{{cite journal |last1=Kaplan |first1=Jonathan Michael |last2=Winther |first2=Rasmus Grønfeldt |date=2014 |title=Realism, Antirealism, and Conventionalism About Race |url=https://philpapers.org/rec/KAPRAA |journal=[[Philosophy of Science (journal)|Philosophy of Science]] |volume=81 |issue=5 |pages=1039–1052 |doi=10.1086/678314 |s2cid=55148854}}</ref><ref>{{cite journal |last=Winther |first=Rasmus Grønfeldt |date=2015 |title=The Genetic Reification of 'Race'?: A Story of Two Mathematical Methods |url=http://philpapers.org/archive/WINTGR.pdf |journal=[[Critical Philosophy of Race]] |volume=2 |issue=2 |pages=204–223}}</ref>{{sfnp|Kaplan|Winther|2013}} and the geneticist [[Joseph L. Graves|Joseph Graves]],<ref>{{Cite web |last=Graves |first=Joseph |date=7 June 2006 |title=What We Know and What We Don't Know: Human Genetic Variation and the Social Construction of Race |url=http://raceandgenomics.ssrc.org/Graves/ |website=Race and Genomics}}</ref> have argued that the cluster structure of genetic data is dependent on the initial hypotheses of the researcher and the influence of these hypotheses on the choice of populations to sample. When one samples continental groups, the clusters become continental, but if one had chosen other sampling patterns, the clustering would be different. Weiss and Fullerton have noted that if one sampled only Icelanders, Mayans and Maoris, three distinct clusters would form and all other populations could be described as being clinally composed of admixtures of Maori, Icelandic and Mayan genetic materials.<ref name="evolutionary" /> Kaplan and Winther therefore argue that, seen in this way, both Lewontin and Edwards are right in their arguments. They conclude that while racial groups are characterized by different allele frequencies, this does not mean that racial classification is a natural taxonomy of the human species, because multiple other genetic patterns can be found in human populations that crosscut racial distinctions. Moreover, the genomic data underdetermines whether one [[Lumpers and splitters|wishes to see subdivisions (i.e., splitters) or a continuum (i.e., lumpers)]]. Under Kaplan and Winther's view, racial groupings are objective social constructions (see Mills 1998<ref>{{cite book |last=Mills |first=Charles W. |author-link=Charles Wade Mills |date=1988 |chapter=But What Are You Really? The Metaphysics of Race |title=Blackness visible: essays on philosophy and race |pages=41–66 |publisher=[[Cornell University Press]] |location=Ithaca, New York}}</ref>) that have conventional biological reality only insofar as the categories are chosen and constructed for pragmatic scientific reasons. In earlier work, Winther had identified "diversity partitioning" and "clustering analysis" as two separate methodologies, with distinct questions, assumptions, and protocols. Each is also associated with opposing ontological consequences vis-a-vis the metaphysics of race.<ref>{{cite web|url=http://philpapers.org/archive/WINTGR.pdf |title=The Genetic Reification of "Race"? A story of two mathematical methods |access-date=15 January 2020}}</ref> Philosopher Lisa Gannett has argued that biogeographical ancestry, a concept devised by [[Mark D. Shriver|Mark Shriver]] and [[Tony Frudakis]], is not an objective measure of the biological aspects of race as Shriver and Frudakis claim it is. She argues that it is actually just a "local category shaped by the U.S. context of its production, especially the forensic aim of being able to predict the race or ethnicity of an unknown suspect based on DNA found at the crime scene".<ref>{{cite journal |last=Gannett |first=Lisa |title=Biogeographical ancestry and race |journal=Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences |date=September 2014 |volume=47 |pages=173–184 |doi=10.1016/j.shpsc.2014.05.017 |pmid=24989973}}</ref>