Biology Reference
In-Depth Information
(also known as blood groups). A blood type is a classification of blood based on the presence
or absence of inherited molecular substances (called
antigens
) on the surface of red blood
cells. By the mid-1900s, multiple blood group types had been discovered, as had similar
protein systems. Anthropologists quickly recognized the potential of blood and protein
groups for the study of variation within and among human groups. Because monogenic
blood groups and proteins were considered to be more fundamental substances than gross
anatomical polygenic features (such as any found on the skeleton), they were also considered
to be more useful for the overt classification of human variation; they subsequently formed
the basis of the “genetical method” of early to mid-twentieth century physical anthropology
(
Boyd, 1939, 1963
).
The field of “anthropological genetics” had its effective beginnings in the 1950s, though it
truly began to assert itself in the 1970s (see
Crawford and Workman, 1973
). While some
physical anthropologists continued to focus their research on the classificatory potential
of blood groups and proteins (now known as
classical markers
), others kept their eye on
theoretical developments in mathematical theory as applied to evolution (also known as
population genetics
), as well as in genetics, biology, and computer science. These fields,
combined with the classical anthropological concern of local and regional biological varia-
tion and adaptation led to the new research program of
anthropological genetics
, aptly
defined in 1980 by Derek F. Roberts as “the study of the genetic variation that occurs within
and between human populations, its origin, and the factors and processes that maintain it”
(1980:419). Indeed, the anthropological genetics research agenda from the 1950s through the
1990s was to document evolutionary process in small, highly isolated, non-Western human
groups. In addition, anthropological geneticists began to engage in the mathematical
modeling of
polygenic traits
, or traits presumed to be controlled by multiple genes (also,
“complex” traits). These include disease traits as well as skeletal and other anatomical
features.
Advances in genetic technology first spurred the onset of a “molecular revolution” in the
1990s, and later, the “genomic revolution” of the 2000s. In response, the field of anthropolog-
ical genetics has been shifting in emphasis from the characterization of
population structure
(how populations are subdivided, if at all, into local or subpopulations) to the study of
human origins and diaspora. In addition, the trend now is movement from indirect inference
to direct analysis of the genetic component of traits by actual mapping of genes and associ-
ated genomic regions. This most recent trend is reflected in the most current definition of
anthropological genetics as “a synthetic discipline that applies the methods and theories of
genetics to evolutionary questions posed by anthropologists” (
Crawford, 2007
:1). See
Table 16.1
.
For More Information
.
The history of the field of anthropological genetics from the 1950s/70s onwards can be
easily tracked by reading through the successive series of edited volumes by Michael Craw-
ford (University of Kansas) and colleagues. These are, in chronological order:
Methods and
Theories of Anthropological Genetics
(
Crawford and Workman, 1973
),
Current Developments in
Anthropological Genetics, Volume I, Theory and Methods
(
Mielke and Crawford, 1980
),
Current
Developments in Anthropological Genetics, Volume II, Ecology and Population Structure
(
Crawford
