In a São Paulo study, 67% of self-identified White participants have an African ancestry estimate above zero. But that is a count of people—not 67% of their DNA. The entire White group's median African estimate is 7.4%.

This distinction opens up the real story: color categories and family history overlap, but they do not match person for person.

Researchers genotyped 841 residents and used 720 unrelated participants for the main comparisons. Across those 720, 80.3% have more than 50% estimated European ancestry.

The self-identified Mixed/Parda group is not defined by an even split between Africa and Europe. Its separate medians are 62.3% European, 26.5% African and 8.5% Indigenous American. Separate medians need not total 100%.

Among Black/Preta participants, the balance shifts: African ancestry has a median of 56.1%. Yet 14 of 74 people in this group—nearly one in five—have European estimates above 50%.

Indigenous American contributions also extend across the three largest groups, with medians of 3.6% in White, 8.5% in Mixed and 5.6% in Black participants.

Behind the overlap lie centuries of colonization, slavery, migration and mixing. The study does not identify exact migration routes or specific ancestral peoples. These are broad, reference-based estimates from a São Paulo city sample; small values depend on the model and references.

The labels relate to ancestry at group level, but cannot tell someone's whole ancestry story or determine their identity. The cover's Rodrigo Santoro portrait is contextual; his personal DNA is not reported here.

Which finding surprised you most?

📚 Source: Pereira et al. (2024), Genes
Genetic Ancestry and Self-Reported “Skin Color/Race” in the Urban Admixed Population of São Paulo City, Brazil

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