Race (human categorization)

==== Ancestrally differentiated populations (clades) ====
In 2000, philosopher Robin Andreasen proposed that [[cladistics]] might be used to categorize human races biologically, and that races can be both biologically real and socially constructed.<ref name="Andreasen 2000" /> Andreasen cited tree diagrams of relative [[genetic distance]]s among populations published by [[Luigi Luca Cavalli-Sforza|Luigi Cavalli-Sforza]] as the basis for a phylogenetic tree of human races (p.&nbsp;661). Biological anthropologist [[Jonathan M. Marks|Jonathan Marks]] (2008) responded by arguing that Andreasen had misinterpreted the genetic literature: "These trees are phenetic (based on similarity), rather than cladistic (based on [[Monophyly|monophyletic]] descent, that is from a series of unique ancestors)."{{sfn|Marks|2008|p=28–29}} Evolutionary biologist [[Alan Templeton]] (2013) argued that multiple lines of evidence falsify the idea of a phylogenetic tree structure to human genetic diversity, and confirm the presence of gene flow among populations.{{sfn|Templeton|2013}} Marks, Templeton, and Cavalli-Sforza all conclude that genetics does not provide evidence of human races.{{sfn|Templeton|2013}}{{sfn|Marks|2008}}

Previously, anthropologists Lieberman and Jackson (1995) had also critiqued the use of cladistics to support concepts of race. They argued that "the molecular and biochemical proponents of this model explicitly use racial categories ''in their initial grouping of samples''". For example, the large and highly diverse macroethnic groups of East Indians, North Africans, and Europeans are presumptively grouped as Caucasians prior to the analysis of their DNA variation. They argued that this ''a priori'' grouping limits and skews interpretations, obscures other lineage relationships, deemphasizes the impact of more immediate clinal environmental factors on genomic diversity, and can cloud our understanding of the true patterns of affinity.<ref name="Lieberman 1995" />

In 2015, Keith Hunley, Graciela Cabana, and Jeffrey Long analyzed the [[Human Genome Diversity Project]] sample of 1,037 individuals in 52 populations,<ref name=":12">{{cite journal |last1=Hunley |first1=Keith L. |last2=Cabana |first2=Graciela S. |last3=Long |first3=Jeffrey C. |author-link3=Jeffrey C. Long |date=1 December 2015 |title=The apportionment of human diversity revisited |journal=[[American Journal of Physical Anthropology]] |volume=160 |issue=4 |pages=561–569 |doi=10.1002/ajpa.22899 |issn=1096-8644 |pmid=26619959|doi-access=free}}</ref> finding that diversity among non-African populations is the result of a serial founder effect process, with non-African populations as a whole nested among African populations, that "some African populations are equally related to other African populations and to non-African populations", and that "outside of Africa, regional groupings of populations are nested inside one another, and many of them are not monophyletic".<ref name=":12" /> Earlier research had also suggested that there has always been considerable gene flow between human populations, meaning that human population groups are not monophyletic.<ref name="Templeton 1998" /> Rachel Caspari has argued that, since no groups currently regarded as races are monophyletic, by definition none of these groups can be clades.{{sfn|Caspari|2003}}