What does Cavalli-Sforza say about biological basis of human race?


Cavalli-Sforza, L. L. (2005). “The Human Genome Diversity Project: past, present and future.” Nature Reviews: Genetics 6: 333-340.

Cavalli-Sforza, L. L., R. Menozzi, et al. (1994). The History and Geography of Human Genes. Princeton, NJ, Princeton University Press.

Cavalli-Sforza’s research projects and Human Genome Diversity Project (HGDP) are often criticized by social scientists and specialists in bioethics, because of the danger of scientific racism.  Cavalli-Sforza (2005) respond back to these and says “Concern that HGDP data would feed ‘scientific racism’ was also expressed by naïve observers, despite the fact that half a century of research into human variation has supported the opposite point of view – that there is no scientific basis for racism.”  Here are quotes from the bock, “The History and Geography of Human Genes” by Cavalli-Sforza and his colleagues (1994) that show Cavalli-Sforza’s position on human race.

“Human races are still extremely unstable entities in the bands of modern taxonomists…”  He thinks how many racial groups you have is subjective and depends on personal preference of researchers who like to lump many populations together or split into many groups.  Also, he recognizes the great variation exists within any human populations.  “As one goes down the scale of the taxonomic hierarchy toward the lower and lower partitions, the boundaries between clusters become even less clear…There is great genetic variation in all populations, even in small ones.”

“From a scientific point of view, the concept of race has failed to obtain any consensus…the major stereotypes, all based on skin color, hair color and form, and facial traits, reflect superficial differences that are not confirmed by deeper analysis with more reliable genetic traits and whose origin dates from recent evolution mostly under the effect of climate and perhaps sexual selection.”

To study human evolution, Cavalli-Sforza and his colleagues use clustering approach with phylogenetic trees.  The phylogenetic trees offer “a simple graphic aid for visualizing those relationships [relationship between different populations] and a path to infer the possible evolutionary history behind them.” However, the clusters they identity in phylogenetic trees are not same as racial groups, because there is not enough genetic differences among human groups.  He says “…we can identify ‘clusters’ of populations and order them in a hierarchy that we believe represents the history of fissions in the expansion to the whole world of anatomically modern humans.  At no level can clusters be identified with races…there is no discontinuity that might tempt us to consider a certain level as a reasonable, though arbitrary, threshold for race distinction.  Minor changes in the genes or methods used shift some populations from one cluster to the other.”

As shown above, despite the criticisms, Cavalli-Sforza believes the arbitrariness of racial classification which is not supported by genetic data.  In his 2005 article, he emphasizes the importance of HGDP in understanding human history and biomedical research.  It is very clear that Cavelli-Sforza is against racial classification, but why is he often criticized by many people?

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