1 In this book, I will only use mestiçagem when referring speciﬁcally to Brazil.
2 La raza in Latin Amer i ca can refer to “a people” conceived as a biocultural unity;
for example, la raza colombiana means “the Colombian people,” understood to
share biology, history, and culture. This book title therefore can mean “the prob-
lems of race in Colombia” but also “the prob lems facing la raza colombiana.”
3 See Wade (2010, 2015:ch. 6), Sanchez and Bryan (2003), Psacharopoulos and Pa-
trinos (1994), Telles and Proj ect on Ethnicity and Race in Latin Amer i ca (2014).
On Mexico speciﬁcally, see also Moreno Figueroa (2010, 2012), and Sue (2013).
4 For details about Rgmla, see the preface.
chapter 1 · Purity and Mixture in Human Population Ge netics
1 Lateral gene transfer occurs when ge ne tic variants are transferred horizontally
between genealogically distinct lineages (common among microbes); hybrid spe-
cies are created when two diﬀerent species breed to produce a new fertile species
(which contradicts the standard deﬁnition of a species); a polygenomic organism
is one that hosts diﬀerent genomes, whether from the same species (e.g., a chi-
mera) or diﬀerent species (e.g., the ratio of microbial to human cells in a human
body was widely reported to be 10:1, although this ﬁgure has recently been re-
vised down to 1:1 [Campbell 2016]).
2 In gwas, it is impor tant to make sure that cases and controls are matched for bga
(i.e., population stratiﬁcation is controlled for). If people with a high proportion
of a given bga are overrepresented among cases, ge ne tic variants that are associ-
ated with that bga will show up as candidate genes, even if they have no influence
on the disease.
3 See Paz’s analy sis of this well- known Mexican phrase, which is usually translated
as “son of a bitch/whore,” but really means “son of the act of fucking up/over”
4 In 2009, I participated with colleagues in a research group in the esRc Centre
for the Research on Socio- Cultural Change (cResc), hosted by the University of
Manchester and the Open University. We discussed the concept of topology at
some length, and I am indebted to these discussions.