A study conducted at the U linking Jewish intelligence and genetic mutation with natural selection is receiving controversial attention by scientists and media alike.
According to the study, Ashkenazi Jews of European descent have high intelligence as well as genetic mutations such as sickle cell anemia due to selective mating and as non-menial work over a number of generations.
The study has received praise as well as heated criticism from The New York Times, The New England Journal of Medicine and The Washington Times.
Henry Harpending, professor of anthropology at the U and one of the professors who participated in the study, said he and his colleagues expected an intense debate when the results of the study were made public.
"Absolutely anything in human biology that is interesting is going to be controversial," Harpending said.
According to the study, Ashkenazi Jews have the highest average IQ of any ethnic group in the world, corresponding to an IQ score of 112-115.
The IQ of an average person is approximately 100, said Gregory Cochran, a U anthropology professor who also participated in the research.
The studied linked the Ashkenazi's above-average IQ to a gene mutation resulting from seclusion from menial work during medieval times.
The Ashkenazi were restricted to entrepreneurial and managerial roles as financiers, estate managers, tax farmers and merchants. As a result, the Ashkenazi Jews developed higher cognitive and verbal skills compared with other groups of the time, the researchers reported.
"These mutations are not a result of chance. They're a result of something," Cochran said.
Above-average intelligence and added economic success led families to marry within the Ashkenazi lineage for a number of centuries, U researchers found.
"This could be a factor in the genetic mutations that have been studied," Harpending said.
As a byproduct of unusually high brain functions, the Ashkenazi population has had a number of documented genetic mutations associated with their bloodline, Harpending said.
Gene mutations resulting in sphingolipid disorders and Tay-Sachs disease, which affects the cell's management of chemicals, were linked to Ashkenazi Jew DNA in the study.
Blood disorders such as sickle cell anemia are a direct consequence of Tay-Sachs, the study noted.
Sphingolipid disorders promote the growth and interconnection of brain cells and mutations in DNA-repair genes, which are involved in Ashkenazi diseases.
Sphingolipid disorders may also unleash growth of neurons, the study concluded.
While the study led researchers to make several conclusions, the evidence is far from conclusive.
"Although our findings are thorough, they are not complete," Harpending said. "More research needs to be conducted."
cogrogan@chronicle.utah.edu
