Short answers, pulled from the story.
The word race did not exist as a biological category in the ancient world. A French physician named François Bernier published a text in the 1680s that introduced the first post-Graeco-Roman classification of humans into distinct races.
The one-drop rule emerged during the Reconstruction era in the United States. This legal and social convention dictated that any person with any known African ancestry was classified as Black regardless of physical appearance or cultural background.
The Human Genome Project revealed in 2000 that there are no genetically defined races. Studies showed that 85 percent of statistical genetic variation exists within local populations while only about 8 percent occurs between large groups living on different continents.
The U.S. National Academies of Sciences, Engineering, and Medicine formally declared in 2023 that researchers should not use race as a proxy for describing human genetic variation. The report released on the 14th of March 2023 argued that classifying people by race is a practice entangled with and rooted in racism.
20th-century Brazil recognized over a dozen racial categories based on a spectrum of skin color, hair texture, and eye color. This system allowed siblings to belong to different racial groups unlike the rigid classifications found in the United States.
In 1735 the Swedish botanist Carl Linnaeus divided the human species Homo sapiens into four continental varieties. He assigned specific personality traits and temperaments to each variety including Homo sapiens europaeus and Homo sapiens afer.