Extra-European Caucasoid

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A term describing non-European Caucasoids from North Africa, Horn of Africa, West Asia, Central Asia and the Indian subcontinent and their descendants in other parts of the world.

Molecular phylogeny researchers using this term are not necessarily asserting that the members of this group are more closely related to each other than to non-members. The word cluster is used both for sets of populations statistically found by cluster analysis to be genetically more similar to each other than to any other populations in the study, but also used for arbitrary groupings. This makes it is easy to mistake an assumption or artifact for a scientific result.

In The History and Geography of Human Genes by Cavalli-Sforza et al. (1994), the average linkage tree diagram of 42 populations (p.78, Fig.2.3.2.B) shows the set of extra-European Caucasoid sample populations as polyphyletic. Cavalli-Sforza et al. grouped 42 sample populations into 9 reasonably compact clusters, although not necessarily genetically closest, including "Caucasoid (extra-European)", for convenience in further analysis (p.79, section 2.3.c).

As the Arguments against races as lineages section of the Race article notes: "the molecular and biochemical proponents of this model explicitly use racial categories in their initial grouping of samples".

It is also necessary to keep in mind that while molecular systematics resulting from cluster analysis is suggestive of a lineage or clade of populations of common descent from a single past ancestor population, it is not proof of a strictly monophyletic origin unless it is already known from other evidence (often archeological instead of genetic) that the member populations of the cluster then stayed in reproductive isolation from other populations.


Contents

[edit] Challenges

[edit] Use of racial categories in modern DNA studies

Modern DNA studies are beginning to throw serious doubt on older "classical" racial categories. The nuclear DNA work of researcher Ann Bowcock (1991, 1994) for example, suggests that such primary groupings as Europeans may be flawed, and that such peoples arose as a consequence of admixture between certain already differentiated African and Asian ancestral stocks. Under this approach to the DNA data, Caucasians are thus not a primary grouping as in the classical categories, but a secondary type or race, due to their supposedly hybrid origins.[1][2]

Anthropologists such as Lieberman and Jackson (1995), also find numerous methodological and conceptual problems with using DNA sequencing methods such as cladistics to support concepts of race. The hold for example that: "the molecular and biochemical proponents of this model explicitly use racial categories in their initial grouping of samples They suggest that the authors of these studies find support for racial distinctions only because they began assuming the validity of race (Leiberman and Jackson 1995 "Race and Three Models of Human Origins" in American Anthropologist 97(2) 231-242)[3]

Whatever the approach used, modern DNA studies have in many ways undermined traditional racial categories in favor of a population variant/gradient or continuum approach, instead of such arbitrary categories of racial distinction, which in its self doesn't reflect the data.

[edit] Application of DNA analysis to Nile Valley populations

In the light of this modern DNA analysis, grouping methods and classifications like Cavalli-Sforza's Extra-European Caucasoid to incorporate various North African peoples like the Egyptians, Ethiopians, and others, has drawn criticism from some scholars (Keita and Kittles 1999) for advocating the language of a non-racial approach, but in practice, using pre-defined, arbitrary categories to hold the data rather than let them speak for themselves. [4] Populations like those in the Nile Valley can have a wide range of variation, hold Kittles and Keita in The Persistence of Racial Thinking and the Myth of Racial Divergence as opposed to pigeonholing them into apriori groupings.[5] As Brown and Armelagos (2001) put it: "In light of this, the low proportion of genetic variance across racial groupings strongly suggests a re-examination of the race concept. It no longer makes sense to adhere to arbitrary racial categories, or to expect that the next genetic study will provide the key to racial classifications."[6]

[edit] DNA racial studies yield contradictory results

Liberman and Jackson (1995), and Ryan and Armelagos(2001) point to contradictory results in DNA racial analysis, in that many studies "select the small proportion of genetic variability that is roughly apportionable by race to plot out dendrograms of essentially false categorizations of human variability. T oaccomplish this, these studies use apriori categorizations of human variability that are based on the inaccurate belief that classical racial categorization schemes delineate a series of isolated breeding populations.." An exampleof contradictory results are seen in the work of such researches as Bowcock, Bowcock, Sforza, et. al, 1994. "Despite a research design that should have maximized the degree to which the researchers were able to classify individuals by racial category, the results are something less than "high resolution" with respect to this goal. For example, 88% of individuals were classified as coming from the right continent, while only 46% were classified as coming from the right region within each continent. Notably, 0% success was achieved in classifying East Asian populations to their region or origin. These results occurred despite the fact that Bowcock and co-workers entered their genetic information into a program that already used the a priori racial categories they were trying to replicate."[7] Ironically, some of Bowcock's data itself contradicts "classical" race categories, suggesting that Caucasoids, rather than being a primary group, are a secondary type or race, a hybrid strain based on certain variants of African and Asian populations.[8]

[edit] See also

[edit] References

  • Cavalli-Sforza, L.L., Menozzi, P. & Piazza, A. The History and Geography of Human Genes Princeton: Princeton University Press, 1994. ISBN 0-691-08750-4
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