Editing One-drop rule (section)

==Racial mixtures of blacks and whites in modern America==
Given the intense interest in ethnicity, genetic [[genealogists]] and other scientists have studied population groups. [[Henry Louis Gates Jr.]] publicized such genetic studies on his two series ''[[African American Lives]],'' shown on [[PBS]], in which the ancestry of prominent figures was explored. His experts discussed the results of autosomal DNA tests, in contrast to direct-line testing, which survey all the DNA that has been inherited from the parents of an individual.<ref name="jh"/> Autosomal tests focus on [[Single-nucleotide polymorphism|SNP]]s.<ref name="jh"/>

The specialists on Gates' program summarized the make-up of the United States population by the following:

* 58 percent of African Americans have at least 12.5% European ancestry (equivalent of one great-grandparent);
* 19.6 percent of African Americans have at least 25% European ancestry (equivalent of one grandparent);
* 1 percent of African Americans have at least 50% European ancestry (equivalent of one parent) (Gates is one of these, he discovered, having a total of 51% European ancestry among various distant ancestors); and
* 5 percent of African Americans have at least 12.5% Native American ancestry (equivalent to one great-grandparent).<ref>Henry Louis Gates, Jr., ''In Search of Our Roots: How 19 Extraordinary African Americans Reclaimed Their Past'' (New York: Crown Publishing, 2009), pp. 20–21.</ref>

In 2002, [[Mark D. Shriver]], a molecular [[anthropologist]] at Penn State University, published results of a study regarding the racial admixture of Americans who identified as white or black:<ref name=Shriver>{{cite web |url=http://www.upi.com/Top_News/2002/05/08/Analysis-White-prof-finds-hes-not-2/UPI-53561020909970/ |title=Analysis: White prof finds he's not |first=Steve |last=Sailer |author-link=Steve Sailer |date=8 May 2002 |work=[[United Press International]] |access-date=12 March 2016}}</ref> Shriver surveyed a 3,000-person sample from 25 locations in the United States and tested subjects for autosomal genetic make-up:

* Of those persons who identified as white:
** Individuals had an average 0.7% black ancestry, which is the equivalent of having 1 black and 127 white ancestors among one's 128 5×great-grandparents.
** Shriver estimates that 70% of white Americans have no African ancestors (in part because a high proportion of current whites are descended from more recent immigrants from Europe of the late 19th and early 20th centuries, rather than those early migrants to the colonies, who in some areas lived and worked closely with Africans, free, indentured or slave, and formed relations with them).
** Among the 30% of identified whites who have African ancestry, Shriver estimates their black racial admixture is 2.3%; the equivalent of having had three black ancestors among their 128 5×great-grandparents.<ref name=Shriver/>
* Among those who identified as black:
** The average proportion of white ancestry was 18%, the equivalent of having 22 white ancestors among their 128 5×great-grandparents.
** About 10% have more than 50% white ancestry.

Black people in the United States are more racially mixed than white people, reflecting historical experience here, including the close living and working conditions among the small populations of the early colonies, when indentured servants, both black and white, and slaves, married or formed unions. Mixed-race children of white mothers were born free, and many families of free people of color were started in those years. 80 percent of the free African-American families in the Upper South in the censuses of 1790 to 1810 can be traced as descendants of unions between white women and African men in colonial Virginia, not of slave women and white men. In the early colony, conditions were loose among the working class, who lived and worked closely together. After the [[American Revolutionary War]], their free mixed-race descendants migrated to the frontiers of nearby states along with other primarily European Virginia pioneers.<ref name=Heinegg /> The admixture also reflects later conditions under slavery, when white planters or their sons, or overseers, frequently raped African women.<ref>Moon, Dannell, "Slavery", in ''Encyclopedia of Rape,'' Merril D. Smith (Ed.), Greenwood Publishing Group, 2004, p. 234.</ref> There were also freely chosen relationships among individuals of different or mixed races.

Shriver's 2002 survey found different current admixture rates by region, reflecting historic patterns of settlement and change, both in terms of populations who migrated and their descendants' unions. For example, he found that the black populations with the highest percentage of white ancestry lived in California and Seattle, Washington. These were both majority-white destinations during the [[Great Migration (African American)|Great Migration]] of 1940–1970 of African Americans from the Deep South of Louisiana, Texas and Mississippi. Blacks sampled in those two locations had more than 25% white European ancestry on average.<ref name=Shriver/>

As noted by Troy Duster, direct-line testing of the Y-chromosome and mtDNA ([[mitochondrial DNA]]) fails to pick up the heritage of many other ancestors.<ref name="hur" /> DNA testing has limitations and should not be depended on by individuals to answer all questions about heritage.<ref name="hur"/> Duster said that neither Shriver's research nor Gates' PBS program adequately acknowledged the limitations of [[genetic testing]].<ref name="hur"/><ref name="bldl1">{{cite web |url=https://www.sciencedaily.com/releases/2007/10/071018145955.htm|title=Genetic Ancestral Testing Cannot Deliver on Its Promise, Study Warns|author=ScienceDaily|access-date=2008-10-02 |year=2008 |publisher=ScienceDaily}}</ref>

Similarly, the Indigenous Peoples Council on Biocolonialism (IPCB) notes that: "Native American markers" are not found solely among Native Americans. While they occur more frequently among Native Americans, they are also found in people in other parts of the world.<ref name="bldl2">{{cite web |last=Tallbear |first=Kimberly |year=2008 |url=http://www.weyanoke.org/historyculture/hc-DNAandIndianAncestry.html |title=Can DNA Determine Who is American Indian? |access-date=2009-10-27 |publisher=The WEYANOKE Association |archive-url=https://web.archive.org/web/20110724191733/http://www.weyanoke.org/historyculture/hc-DNAandIndianAncestry.html |archive-date=24 July 2011 |url-status=dead }}</ref> Genetic testing has shown three major waves of ancient migration from Asia among Native Americans but cannot distinguish further among most of the various tribes in the Americas. Some critics of testing believe that more markers will be identified as more Native Americans of various tribes are tested, as they believe that the early epidemics due to [[smallpox]] and other diseases may have altered genetic representation.<ref name="hur"/><ref name="bldl1"/>

Much effort has been made to discover the ways in which the one-drop rule continues to be socially perpetuated today. For example, in her interview of black/white adults in the South, Nikki Khanna uncovers that one way the one-drop rule is perpetuated is through the mechanism of reflected appraisal. Most respondents identified as black, explaining that this is because both black and white people see them as black as well.<ref>{{cite journal |last=Khanna |first=Nikki |title=If you're half black, you're just black: Reflected Appraisals and the Persistence of the One-Drop Rule |journal=The Sociological Quarterly |volume=51 |issue=5 |pages=96–121 |year=2010 |citeseerx=10.1.1.619.9359 |s2cid=145451803 |doi=10.1111/j.1533-8525.2009.01162.x}}</ref>