Chapters 3–7 begins an extended examination of genomic science and its participation in multiculturalist assemblages in each nation, drawing on data collected during a three-year research project, “Race, Genomics, and Mestizaje in Latin America.” Chapter 3 describes changes in genetic science from the 1990s and outlines shifts toward multiculturalism in Brazil, Colombia, and Mexico.

Chapter 8 turns to the gendered aspect of mestizaje, exploring narratives which describe European men having sex with indigenous and African women. Genomics addresses this with data about mitochondrial DNA (mtDNA, inherited via the material line) and Y-chromosome DNA (inherited by men from their fathers). The data paint a picture in which European men are given sexual agency and assumed to be dominant, while indigenous and African women are seen as passive recipients, and black and indigenous men (and European women) are placed in the background.