Based on a collaborative project involving academics from three Latin American countries (Brazil, Colombia and Mexico) under the general coordination of a UK-based anthropologist, Mestizo Genomics explores how national (and often gendered) narratives about mestizaje and race affect genomic research on population diversity. The book emphasises how genomics can contribute to reshaping these discourses, highlighting the permeability of the boundary between science and society.

Set within a general science and technology studies framework, and with each chapter written by different researchers involved in the project, the book is divided into two distinct parts. The first, ‘History and Context’, introduces the reader to the historical relations between science, race and nation-building in each of the three countries studied. The first chapter, on Brazil, provides a useful historical account, particularly for readers with no background in Latin America. The authors explore the role of scientific racism within debates about mestiçagem in this country as well as the elite's whitening plans for their nation in the nineteenth and early twentieth centuries. They then discuss how population genomic research features in contemporary debates on national identity and affirmative action. The second chapter focuses on how the field of population genomics originated and developed in Colombia. This chapter shows how the emphasis some researchers place on studying isolated and/or ‘unknown’ indigenous and Afro-Colombian communities was in direct dialogue with regional ideas about racial and ethnic difference. This emphasised the idea of diversity within the Colombian population, echoing voices that advocated for a greater presence of multiculturalism within Colombian politics. At the same time, other research projects in Colombia actually focused on admixture as the defining feature of its population, which underlines how population genomics is a far from homogeneous field in this country. The third chapter explores the historical centrality of the mestizo throughout Mexican history, while also describing the process of how the Mexican Research Institute on Genetics-INMEGEN was founded, and the political negotiations needed to guarantee its survival. These last two chapters, on Colombia and Mexico, do not devote as much historical detail to the importance of race and mestizaje discourses as the chapter on Brazil. That said, they provide the reader with the political context necessary to fully understand the field case studies presented in the second part of the book, entitled ‘Laboratory Case Studies’.

Using a mixture of participant observation in laboratories and in-depth interviews with key actors such as geneticists, the second part of the book shows the intriguing on-the-ground processes through which ‘slippery’ notions of race in Latin America feature in genomic studies. The empirical chapters clearly illustrate that, although geneticists claim that their work does not adhere to race as a paradigmatic concept, their practice makes ample use of race-like categories. By relying on ethnographic examples, the authors explore how racialised and gendered narratives of racial mixture (mostly between European men and indigenous and African women) intersect with notions of regional differences within countries. In general, these case studies have the merit of tackling narratives of admixture and regional difference by critically analysing local research practices that oftentimes reify these notions. Each case study nonetheless has specific features. The Brazilian case study is a good example of how genomics research intersects with gendered and racialised local narratives about regional identity and difference. The empirical chapter on Colombia, in turn, contributes to refocusing the analytical boundaries of the book from the national context to the international science-making setting. This chapter also shows in an ethnographic way the debates around the explicit rejection of existing racial categories by a local research team. This resulted in tensions between their willingness to use categories that better expressed local reality and the need to use more established racial categories in order to get their work published in international scientific journals. The Mexican case study highlights how the notion of mestizaje ends up retaining a central place in scientific genomic research, and reveals the growing importance of genomic research applied to biomedicine in this region. The final chapter, written by Wade, reflects on how looking at the centrality of the mestizo through the lens of genomics may help us to understand the historical connections (and contradictions) between national and scientific discourses on admixture, citizenship and multiculturalism. As a result, Wade reveals how race is gradually transfigured into new idioms and areas. This chapter is crucial since the book evidently gains greater cohesion through the three separate case studies being linked together by a more general and comparative discussion.

Caught between the desire to provide a general overview of the region and to show the specificities of how notions of race get both fixed and undone through genomics research in each of the three countries involved, Mestizo Genomics has some potential weaknesses, most of which are related to the ambitious nature of the project. For example, I feel that the methodology and the theoretical concerns expressed by the different research teams could have been more unified. Also importantly, the researchers could have engaged more deeply with critical race and gender theories in each one of the case studies. These drawbacks, however, are sufficiently compensated for by the wide-ranging and comparative aim of the project, by its originality, and by the thought-provoking discussions contained in each chapter. The final part of the book, particularly, helps to establish this research as a solid basis from which to engage with a whole variety of topics such as ethics in genomics research, public policy and identity politics. The most obvious audience for this work is scholars of Latin American studies of race and ethnicity, particularly those with an interest in how developing notions of race intersect with contemporary scientific practices. In addition, the book will be of interest to those involved in the burgeoning field of science and technology studies in the countries considered, as well as to readers interested in the connection between scientific knowledge and narratives of national identity.