This article examines discourses and practises in the professional network of people and organisations in South Africa that comprise the bone marrow/haematopoietic stem cell transplantation (BMT) network. A prominent discursive inter-relationship asserts that some genetically inherited Human Leukocyte Antigen (HLA) types appear in certain ethnic populations more commonly than others, meaning that patients are most likely to find a transplant match with someone in the same ethnic group. The South African BMT network efforts to increase the number of donors from ethnic groups not well represented on the registry are crucial given South Africa's unique and diverse gene pool. This inter-relationship is at the heart of a complex interweaving of genomics, ethnicity, culture, South African nationhood, and the limits of bodily integrity. It necessitates serious engagement in health resource inequalities and burgeoning biosocial identities in a diverse South Africa, especially given its history and its contemporary political agenda of transformation. The analysis of fieldwork is particularly informed by Troy Duster's concept of feedback loops and Paul Rabinow's work on biosociality. Drawing from this analysis, the article also suggests possibilities for policy and practical application.