The greatest challenge facing the emergence of precision medicine is the lack of diversity in studied populations. To address this gap, it is critical to consider ancestral diversity that reflects the global distribution of human genetic variation, as well as acknowledge a distinction between ancestry and race to better understand the interactions between social identities, genetics, and scientific method. In this work, I analyzed genomes from patients with Parkinson’s disease (PD) and melanoma to test the hypothesis that skin pigmentation genes contribute to PD risk. We discovered novel gene variants that contribute to disease risk in PD patients who carry these variants, highlighting the importance of identifying genes and specific molecular pathways to obviate references to race in genetic studies. From a broader perspective, this work identifies a need for inclusion of genetic ancestry in precision medicine to develop targeted therapies for diverse populations and to narrow persistent health disparities.