One-drop rule

The one-drop rule is a historical colloquial term in the United States for the social classification as black of individuals with any African ancestry; it is an example of hypodescent, the automatic assignment of children of a mixed union between different socioeconomic or ethnic groups to the group with the lower status. The one-drop rule was put into law in the twentieth century, for instance in Virginia under the Racial Integrity Act of 1924 (following the passage of similar laws in numerous other states). Despite the strictures of slavery, in the antebellum years free people could have up to one-eighth to one-quarter African ancestry (depending on the state) and be considered legally white. Community acceptance, carrying out community responsibilities, and appearance were often the most important factors if a person's racial status were questioned.

Similarly in the United States, people of partial Native American descent were usually classified as Native American. In the early years of these types of unions and marriages, the fathers were usually European and the mothers Native American. Most Native American tribes had matrilineal descent systems, so within those communities, they also considered the children to belong to the mother's people.

The concept of the one-drop rule has been chiefly applied to those of sub-Saharan black African ancestry. The poet Langston Hughes wrote in his 1940 memoir: "You see, unfortunately, I am not black. There are lots of different kinds of blood in our family. But here in the United States, the word 'Negro' is used to mean anyone who has any Negro blood at all in his veins. In Africa, the word is more pure. It means all Negro, therefore black. I am brown."

Legislation and practice
Both before and after the American Civil War, many people of mixed ancestry who "looked white" and were of mostly white ancestry were legally absorbed into the white majority. State laws established differing standards. For instance, in 1822 Virginia law stated that to be defined as "mulatto" (that is, multi-racial), a person had to have at least one-quarter (equivalent to one grandparent) African ancestry. This was a looser definition than the state's twentieth-century "one-drop rule" under the Racial Integrity Act. This defined a person as legally "colored" (black) for classification and legal purposes if the individual had any African ancestry.

Prominent examples of persons of mostly white ancestry who were accepted by the white community in the nineteenth century were most of Thomas Jefferson's alleged mixed-race descendants or relatives. Three of the four surviving children by Sally Hemings, believed to be fathered by a member of the Jefferson family and therefore up to seven-eighths white by ancestry, moved into the white community. In terms of a larger group, the Melungeons are a group of families of mostly European and African ancestry. Their descendants are documented as having tended to marry persons classified as "white". Their descendants became accepted by the majority culture from the nineteenth into the twentieth centuries.

The one-drop rule was made law, chiefly in the U.S. South but also in other states, in the twentieth century – decades after the Civil War, emancipation and Reconstruction. From the late 1870s on, white Democrats regained political power in the former Confederate states and passed racial segregation laws controlling public facilities, and laws and constitutions to achieve disfranchisement of most blacks from 1890–1910. Many poor whites were also disfranchised in these years, by changes to voter registration rules that worked against them, such as literacy tests, longer residency requirements and poll taxes.

The first challenges to such state laws were overruled by US Supreme Court decisions that upheld state constitutions that effectively disfranchised many, and Plessy v. Ferguson, which allowed racial segregation of public facilities. White Democratic-dominated legislatures proceeded with passing Jim Crow laws that instituted racial segregation in public places and accommodations, and passed other restrictive voting legislation.

Jim Crow laws reached their greatest influence during the decades from 1910–1930. Among them were hypodescent laws, defining as black anyone with any black ancestry, or with a very small portion of black ancestry. Tennessee adopted such a "one-drop" statute in 1910, and Louisiana soon followed. Then Texas and Arkansas in 1911, Mississippi in 1917, North Carolina in 1923, Virginia in 1924, Alabama and Georgia in 1927, and Oklahoma in 1931. During this same period, Florida, Indiana, Kentucky, Maryland, Missouri, Nebraska, North Dakota, and Utah retained their old "blood fraction" statutes de jure, but amended these fractions (one-sixteenth, one-thirtysecond) to be equivalent to one-drop de facto.

Before 1930, individuals of visible mixed European and African ancestry were usually classed as mulattoes, or sometimes as black and sometimes as white, depending on appearance. Previously, most states had limited trying to define ancestry before "the fourth degree" (great-great-grandparents).

In the case of mixed-race Native American and European descendants, the one-drop rule of definition in Virginia was extended only so far as those with more than one-sixteenth Indian blood. This was due to what was known as the "Pocahontas exception." Since many influential First Families of Virginia (FFV) claimed descent from the American Indian Pocahontas of the colonial era, the Virginia General Assembly declared that an individual could be considered white if having no more than one-sixteenth Indian "blood" (the equivalent of one great-great-grandparent).

The eugenicist Madison Grant of New York wrote in his book, The Passing of the Great Race: "The cross between a white man and an Indian is an Indian; the cross between a white man and a Negro is a Negro; the cross between a white man and a Hindu is a Hindu; and the cross between any of the three European races and a Jew is a Jew."

Through the 1940s, Walter Plecker of Virginia and Naomi Drake of Louisiana had an outsize influence. As the Registrar of Statistics, Plecker insisted on labeling mixed-race families of European-African ancestry as black. In 1924, Plecker wrote, "Two races as materially divergent as the White and Negro, in morals, mental powers, and cultural fitness, cannot live in close contact without injury to the higher." A subtext was the assumption that Blacks were somehow "improved" through White admixture. In the 1930s and 1940s, Plecker directed offices under his authority to change vital records and reclassify certain families as colored (without notifying them) after Virginia established a binary system under its Racial Integrity Act of 1924. He also classified people formerly self-identified as Indian, as black. When the U.S. Supreme Court outlawed Virginia's ban on inter-racial marriage in Loving v. Virginia (1967), it also declared Plecker's Virginia Racial Integrity Act and the one-drop rule unconstitutional.

Many people in the US, among various ethnic groups, continue to have their own concepts related to the one-drop ideas. They may still consider multiracial individuals with any African ancestry to be black, or at least non-white (if the person has other minority ancestry), unless the person explicitly identifies as white. Today's ideas have also been influenced by the Black Power Movement and leaders within the black community, who have claimed as black those persons with any African ancestry, regardless of how they self-identified. In the late 20th and early 21st century, some writers consider this another kind of one-drop rule.

Other countries of the Americas
The one-drop rule is nearly unique to the United States and relates both to the Southern slave culture and racial discrimination after emancipation, as well as the Black Power Movement of the 20th century. People in most other countries tend to treat race less rigidly, both in their self-identification and how they regard others. Just as a person with physically recognizable sub-Saharan ancestry can claim to be black in the United States, someone with recognizable Caucasian ancestry may be considered white in Brazil, even if mixed race.

In the caste system of colonial Spanish America, a racial and class hierarchy developed in the society. Many soldiers and explorers took indigenous women as wives, but in time, upper class men were able to bring Spanish women to the colonies. Combined with the Iberian purity of blood rules, the hierarchy classified those with pure Spanish blood and wealth at the top. For the rest, the status of a mixed-race person would be determined by the proportion of "white blood"; an elaborate system classified the combinations of black, Amerindian and white by different names. A proportion of Spanish (white) ancestry was enough to position a person above (or later, African.)  Racial caste not only depended on ancestry or skin color, but also could be raised or lowered by the person's economical fortune. After the abolition of slavery and Latin American independence, the caste divisions blurred into wider groups.

In December 2002, the Washington Post ran a story on the one-drop theory. In the reporter's opinion: "Someone with Sidney Poitier's deep chocolate complexion would be considered white if his hair were straight and he made a living in a profession. That might not seem so odd, Brazilians say, when you consider that the fair-complexioned actresses Rashida Jones ('Boston Public' and 'The Office') and Lena Horne are identified as black in the United States."

According to Jose Neinstein, a native white Brazilian and executive director of the Brazilian-American Cultural Institute in Washington, in the United States, "If you are not quite white, then you are black." However, in Brazil, "If you are not quite black, then you are white." Neinstein recalls talking with a man of Poitier's complexion when in Brazil: "We were discussing ethnicity, and I asked him, 'What do you think about this from your perspective as a black man?' He turned his head to me and said, 'I'm not black,' . . . It simply paralyzed me. I couldn't ask another question."

The Washington Post story also described a Brazilian-born woman who for 30 years before immigrating to the United States considered herself a morena. Her skin had a caramel color that is roughly equated with whiteness in Brazil and some other Latin American countries. "I didn't realize I was black until I came here," she explained. "'Where are you from?' they ask me. I say I'm from Brazil. They say, 'No, you are from Africa.' They make me feel like I am denying who I am."

The same racial culture shock has come to hundreds of thousands of dark-skinned immigrants to the United States from Brazil, Colombia, Panama, and other Latin American nations. Although many are not considered black in their homelands, they have often been considered black in US society. According to the Washington Post, their refusal to accept the United States' definition of black has left many feeling attacked from all directions. At times, white Americans might discriminate against them for their black skin; African Americans might believe that Afro-Latino immigrants are denying their blackness; and they think lighter-skinned Latinos dominate Spanish-language television and media. A majority of Latin Americans possess some African or Native American ancestry. Many of these immigrants feel it is hard enough to accept a new language and culture without the additional burden of having to transform from white to black. Yvette Modestin, a dark-skinned native of Panama who worked in Boston, said the situation was overwhelming: "There's not a day that I don't have to explain myself."

Professor J.B. Bird has said that Latin America is not alone in rejecting the United States' notion that any visible African ancestry is enough to make one black: "In most countries of the Caribbean, Colin Powell would be described as a Creole, reflecting his mixed heritage. In Belize, he might further be described as a 'High Creole', because of his extremely light complexion." This shows that the perception of race, particularly concerning people of black heritage, is relative to each individual person or a people.

Racial mixtures of blacks and whites in modern America
Given the intense interest in ethnicity, genetic genealogists and other scientists have studied the make-up of populations. Henry Louis Gates, Jr. publicized such genetic studies on his two series African American Lives, shown on PBS. The specialists which the show relied on summarized population figures this way: Mark D. Shriver, a molecular anthropologist at Penn State University, has studied population with a team of researchers. In 2002 they published results of a study regarding the racial admixture of Americans who identified as white or black. They recorded the individual's self-identification and analyzed the genetic make-up of their chromosomes. Their results are estimates and might not be completely accurate. Other researchers have also done population studies.
 * 58 percent of African Americans have at least 12.5 percent European ancestry (equivalent of one great-grandparent);
 * 19.6 percent of African Americans have at least 25 percent European ancestry (equivalent of one grandparent);
 * 1 percent of African Americans have at least 50 percent European ancestry (equivalent of one parent) (Gates is one of those, he discovered); and
 * 5 percent of African Americans have at least 12.5 percent Native American ancestry (equivalent to one great-grandparent).

Shriver surveyed a 3,000-person sample from 25 locations in the United States, and tested them for genetic make-up. Among those who self-identified as white, the black racial admixture was about 0.7%; which is the equivalent of having 1 black and 127 white ancestors among one's 128 5xgreat-grandparents. Nationwide, Shriver estimates that 70% of white Americans have no African ancestors (in part because of the greatly increased immigration from Europe in the late nineteenth and early twentieth centuries). Among the 30% who do have African ancestry, Shriver estimates their black racial admixture is 2.3%; the equivalent of having had 3 black ancestors among their 128 5xgreat-grandparents.

Blacks are more racially mixed than whites, reflecting historical experience in the United States, both the close living and working conditions among colonial indentured servants and slaves, when many married or formed unions. Most of the free African-American families in Virginia in colonial years were the descendants of white women and African men. After the American Revolutionary War, their descendants migrated to nearby states along with other Virginia pioneers. The admixture also reflects conditions under slavery, when African women were often taken advantage of by white planters or their sons, or overseers. Their ancestry also reflects freely chosen relationships among individuals of different or mixed races.

Shriver's study is not complete. In his study, of those persons who identified as black, their total ancestry reveals 18% white ancestry, the equivalent of having 22 white ancestors among the 128 5xgreat-grandparents. About 10% of blacks have more than 50% white ancestors. Population studies by researchers other than Shriver have found that in general, blacks had an average white ancestry of 25–30%.

Shriver points out that his survey found different admixture rates by region, which would also reflect historic patterns of settlement and change, both in terms of populations who migrated and their descendants' marriages. For example, the black populations with the highest average white ancestry lived in California and Seattle. Blacks sampled in those two locations had more than 25% white European ancestry on average.

Allusions
The one-drop rule and its consequences have been the subject of several works of popular culture. In the musical Show Boat, Steve, a white man who is married to a black woman, is pursued by the sheriff, who is going to arrest Steve and charge him with miscegenation. Steve pricks his wife's finger and swallows some of her blood. When the sheriff arrives, Steve asks him whether he would consider a man to be white if he had "negro blood" in him. The sheriff replies that "one drop of Negro blood makes you a Negro in these parts". Steve tells the sheriff that he has "more than a drop of negro blood in me". After being assured by others that Steve is telling the truth, the sheriff leaves without arresting Steve.

Preponderance of ancestry
Increasingly, the one-drop rule and the reverse one-drop rule are being replaced by another methodology of deciding who is black and white. In this definition, a person's race is expressed in terms of where most of their ancestors come from.

After the completion of the Human Genome Project it became evident that the concept of "race" is not reflected in the human genetic makeup. Although genetic variation does reflect genetic ancestry and patterns of human migration, an individual's race can not be determined by analysis of their DNA. Therefore, while the concept of race still exists on a social level, on a genetic level "race" does not exist:

"DNA studies do not indicate that separate classifiable subspecies (races) exist within modern humans. While different genes for physical traits such as skin and hair color can be identified between individuals, no consistent patterns of genes across the human genome exist to distinguish one race from another. There also is no genetic basis for divisions of human ethnicity. People who have lived in the same geographic region for many generations may have some alleles in common, but no allele will be found in all members of one population and in no members of any other. Indeed, it has been proven that there is more genetic variation within races than exists between them."

According to J. Phillipe Rushton, a modern proponent of scientific racism who promotes the notion that gaps in IQ scores between races represent genetic differences between these races.:

"Yes, to a certain extent all the races blend into each other. That is true in any biological classification system. However, most people can be clearly identified with one race or another. In both everyday life and evolutionary biology, a "Black" is anyone most of whose ancestors were born in sub-Saharan Africa. A "White" is anyone most of whose ancestors were born in Europe. And an "Oriental" is anyone most of whose ancestors were born in East Asia. Modern DNA studies give rather much the same results."

According to Michael Levin:

"Hybrid populations with multiple lines of descent are to be characterized in just those terms: as of multiple descent. Thus, American Negroids are individuals most of whose ancestors from 15 to 5000 generations ago were sub-Saharan African. Specifying 'most' more precisely in a way that captures ordinary usage may not be possible. '> 50%' seems too low a threshold; my sense is that ordinary attributions of race begin to stabilize at 75%."

Meanwhile, the company DNAPrint Genomics analyzes DNA to estimate the percentage of Indo-European, sub-Saharan, East Asian, and Native American heritage someone has and assigns the person to the category White, Black, East Asian, Native American, or mixed race accordingly. According to U.S. sociologist Troy Duster and ethicist Pilar Ossorio:

"Some percentage of people who look white possess genetic markers indicating that a significant majority of their recent ancestors are African. Some percentage of people who look black will possess genetic markers indicating the majority of their recent ancestors were European."

Pencil test
During the system of apartheid in South Africa, one drop of sub-Saharan blood was not enough to be considered black. South African law maintained a major distinction between those who were black and those who were coloured.

When it was unclear from a person's physical appearance what racial classification they belonged to, the pencil test was employed. This involved inserting a pencil in a person's hair to determine if the hair was nappy enough for the pencil to get stuck. If it fell through they were classified as "White" (or "Coloured", depending on other subjective classification considerations); if the pencil did not fall through, they were classified differently ("Coloured" or "Black", also depending on other subjective classification considerations).

Authorities used this type of test during the apartheid era in South Africa to "ascertain" a person's race.

In the absence of any centralized method, this and other subjective tests were used in various places across South Africa as part of the Population Registration Act of 1950.

Members of the same family who had different hair textures would find themselves in different race groups as a result of this test. This presented serious consequences for many families such as Population Registration Act, Pass Law, Group Areas Act, District Six.