In a 2002 class-action lawsuit against companies that built wealth off slaves, the court demanded that the plaintiffs prove they were descendant from former slaves. The plaintiffs used genetic testing to prove their relationship to different nation groups in Africa. Alondra Nelson, dean of social science at Columbia University, explored the cultural and political meaning of DNA testing in her latest book The Social Life of DNA: Race, Reparations, and Reconciliation after the Genome, published earlier this year.