[Taxacom] Race and taxonomy

Tue Oct 7 11:10:42 CDT 2008

Hi Tom and Pierre,

You are right - meaningful carries a high degree of uncertaintly with 
respect to whet is meant. And, you are right about the consequences of 
our being a very mobile species. However, even the most ardent opponents 
to the validity of the concept of race will admit that in areas that are 
still isolated (e.g., parts of Africa, South America, New Guinea, 
Australia, etc., there are clear indications of easily identifiable 
genetic differences. So, do these populations warrant recognition?

A report just out in Nature describes a new procedure for non-invasive 
detection of Down syndrome. The authors make an interesting point with 
respect to the DNA sequences they can detect: these "sequences often 
vary between populations, so the tests may not work on people from 
different ethnic groups." What is hidden here is that, according to 
various sociologists and anthropologists, "ethnic group" is code for 
"race".

Another interesting study that appeared recently demonstrated that it 
was possible to identify the "racial" origin of individuals based on the 
occurrence of alleles associated with skin color (Asian versus 
Caucasian). This was based on (hold your breath) a measure of "overall 
similarity" derived as a function of alleles for 22 loci (I may not have 
the exct description of the data right, but I think you get my drift).

Many physical anthropologists base their dismissal of the existence of 
races on two observations: 1) genetic variation is clinal - the very 
fuzziness that Pierre refers to; of course, if you ignore the middle of 
the cline than the end points are clearly recognized as different; 2) 
the lack of diagnostic markers - no phenotypic or genetic trait is 
unique to any so-called race.

Cheers,

Dick J

Richard Jensen, Professor
Department of Biology
Saint Mary’s College
Notre Dame, IN 46556
Tel: 574-284-4674

Thomas G. Lammers wrote:
> At 07:45 AM 10/7/2008, Richard Jensen wrote:
>> I think the bottom line is, is there any justification to the concept
>> that there are recognizable subsets of tyhe human species, whether we
>> call them subspecies or races or populations, etc. I presume we ar all
>> aware that, in terms of genetic variation, total variation among samples
>> of humans is dominated by "within" population variation, with only about
>> 4-6 % of the total representing among-population variation. Thus, the
>> argument that the greatest difference between any two randomly chosen
>> individuals from two different continents is less than the difference
>> between any two randomly chosen individuals from the same continent.
>>
>> My question is, Is the variation that allows us to determine, with a
>> high degree of probability, that my ancestry is from northern Europe and
>> my colleagues' ancestry is from, say, western Africa or eastern Asia,
>> biologically meaningful?
>
> It depends on what you mean by "meaningful." That word indicates 
> judgment and interpretation. I would be happy to say that the 
> variation is biological, period. Beyond that would be dicey.
>
> I think that we might say that the variation observed was more 
> meaningful in pre-industrial pre-literate times, before travel became 
> easy and migration rates among populations skyrocketed. Presumably, 
> the genes that became most common in a given population were those 
> that conferred some advantage in survivorship and/or reproduction. 
> Today, with increased gene flow among populations and development of 
> culture that can buffer us from the sorts of natural selection our 
> ancestors were subjected to, the differences we see today likely are 
> no longer meaningful, merely the persistence of a now-defunct world.
>
>
> *Thomas G. Lammers*, Ph.D.
>
> Associate Professor and Curator of the Herbarium (OSH)
> Department of Biology and Microbiology
> University of Wisconsin Oshkosh
> Oshkosh, Wisconsin 54901-8640 USA
>
> *e-mail: * lammers at uwosh.edu
> *phone*: 920-424-1002
> *fax: * 920-424-1101
>
> Plant systematics; classification, nomenclature, evolution, and 
> biogeography of the Campanulaceae /s. lat.
>
> *Webpages:
> */http://www.uwosh.edu/departments/biology/Lammers.htm
> http://www.uwosh.edu/departments/biology/herbarium/herbarium.html
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> /-----------------------------------------------------------
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